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main.c

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  • main.c 32.54 KiB
    #include <stdio.h>
    #include <stm32f4xx.h>
    #include <stm32f4xx_rcc.h>
    #include <stm32f4xx_gpio.h>
    #include <stm32f4xx_tim.h>
    #include <stm32f4xx_pwr.h>
    #include <stm32f4xx_rtc.h>
    #include <stm32f4xx_usart.h>
    #include <stm_misc.h>
    #include "std.h"
    
    #include "misc.h"
    #include "mpyconfig.h"
    #include "gc.h"
    #include "systick.h"
    #include "led.h"
    #include "lcd.h"
    #include "storage.h"
    #include "mma.h"
    #include "usart.h"
    #include "usb.h"
    #include "ff.h"
    #include "timer.h"
    #include "audio.h"
    
    static FATFS fatfs0;
    
    extern uint32_t _heap_start;
    
    void flash_error(int n) {
        for (int i = 0; i < n; i++) {
            led_state(PYB_LED_R1, 1);
            led_state(PYB_LED_R2, 0);
            sys_tick_delay_ms(250);
            led_state(PYB_LED_R1, 0);
            led_state(PYB_LED_R2, 1);
            sys_tick_delay_ms(250);
        }
        led_state(PYB_LED_R2, 0);
    }
    
    static void impl02_c_version(void) {
        int x = 0;
        while (x < 400) {
            int y = 0;
            while (y < 400) {
                volatile int z = 0;
                while (z < 400) {
                    z = z + 1;
                }
                y = y + 1;
            }
            x = x + 1;
        }
    }
    
    #define PYB_USRSW_PORT (GPIOA)
    #define PYB_USRSW_PIN (GPIO_Pin_13)
    
    void sw_init(void) {
        // make it an input with pull-up
        GPIO_InitTypeDef GPIO_InitStructure;
        GPIO_InitStructure.GPIO_Pin = PYB_USRSW_PIN;
        GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
        GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
        GPIO_Init(PYB_USRSW_PORT, &GPIO_InitStructure);
    }
    
    int sw_get(void) {
        if (PYB_USRSW_PORT->IDR & PYB_USRSW_PIN) {
            // pulled high, so switch is not pressed
            return 0;
        } else {
            // pulled low, so switch is pressed
            return 1;
        }
    }
    
    void __fatal_error(const char *msg) {
        lcd_print_strn("\nFATAL ERROR:\n", 14);
        lcd_print_strn(msg, strlen(msg));
        for (;;) {
            flash_error(1);
        }
    }
    
    #include "nlr.h"
    #include "misc.h"
    #include "lexer.h"
    #include "lexerstm.h"
    #include "mpyconfig.h"
    #include "parse.h"
    #include "compile.h"
    #include "runtime.h"
    #include "repl.h"
    
    static qstr pyb_config_source_dir = 0;
    static qstr pyb_config_main = 0;
    
    py_obj_t pyb_source_dir(py_obj_t source_dir) {
        pyb_config_source_dir = py_obj_get_qstr(source_dir);
        return py_const_none;
    }
    
    py_obj_t pyb_main(py_obj_t main) {
        pyb_config_main = py_obj_get_qstr(main);
        return py_const_none;
    }
    
    // sync all file systems
    py_obj_t pyb_sync(void) {
        storage_flush();
        return py_const_none;
    }
    
    py_obj_t pyb_delay(py_obj_t count) {
        sys_tick_delay_ms(py_obj_get_int(count));
        return py_const_none;
    }
    
    py_obj_t pyb_led(py_obj_t state) {
        led_state(PYB_LED_G1, rt_is_true(state));
        return state;
    }
    
    py_obj_t pyb_sw(void) {
        if (sw_get()) {
            return py_const_true;
        } else {
            return py_const_false;
        }
    }
    
    /*
    void g(uint i) {
        printf("g:%d\n", i);
        if (i & 1) {
            nlr_jump((void*)(42 + i));
        }
    }
    void f(void) {
        nlr_buf_t nlr;
        int i;
        for (i = 0; i < 4; i++) {
            printf("f:loop:%d:%p\n", i, &nlr);
            if (nlr_push(&nlr) == 0) {
                // normal
                //printf("a:%p:%p %p %p %u\n", &nlr, nlr.ip, nlr.sp, nlr.prev, nlr.ret_val);
                g(i);
                printf("f:lp:%d:nrm\n", i);
                nlr_pop();
            } else {
                // nlr
                //printf("b:%p:%p %p %p %u\n", &nlr, nlr.ip, nlr.sp, nlr.prev, nlr.ret_val);
                printf("f:lp:%d:nlr:%d\n", i, (int)nlr.ret_val);
            }
        }
    }
    void nlr_test(void) {
        f(1);
    }
    */
    
    void fatality(void) {
        led_state(PYB_LED_R1, 1);
        led_state(PYB_LED_G1, 1);
        led_state(PYB_LED_R2, 1);
        led_state(PYB_LED_G2, 1);
    }
    
    static const char fresh_boot_py[] =
    "# boot.py -- run on boot-up\n"
    "# can run arbitrary Python, but best to keep it minimal\n"
    "\n"
    "pyb.source_dir('/src')\n"
    "pyb.main('main.py')\n"
    "#pyb.usb_usr('VCP')\n"
    "#pyb.usb_msd(True, 'dual partition')\n"
    "#pyb.flush_cache(False)\n"
    "#pyb.error_log('error.txt')\n"
    ;
    
    // get lots of info about the board
    static py_obj_t pyb_info(void) {
        // get and print clock speeds
        // SYSCLK=168MHz, HCLK=168MHz, PCLK1=42MHz, PCLK2=84MHz
        {
            RCC_ClocksTypeDef rcc_clocks;
            RCC_GetClocksFreq(&rcc_clocks);
            printf("S=%lu\nH=%lu\nP1=%lu\nP2=%lu\n", rcc_clocks.SYSCLK_Frequency, rcc_clocks.HCLK_Frequency, rcc_clocks.PCLK1_Frequency, rcc_clocks.PCLK2_Frequency);
        }
    
        // to print info about memory
        {
            extern void *_sidata;
            extern void *_sdata;
            extern void *_edata;
            extern void *_sbss;
            extern void *_ebss;
            extern void *_estack;
            extern void *_etext;
            printf("_sidata=%p\n", &_sidata);
            printf("_sdata=%p\n", &_sdata);
            printf("_edata=%p\n", &_edata);
            printf("_sbss=%p\n", &_sbss);
            printf("_ebss=%p\n", &_ebss);
            printf("_estack=%p\n", &_estack);
            printf("_etext=%p\n", &_etext);
            printf("_heap_start=%p\n", &_heap_start);
        }
    
        // GC info
        {
            gc_info_t info;
            gc_info(&info);
            printf("GC:\n");
            printf("  %lu total\n", info.total);
            printf("  %lu : %lu\n", info.used, info.free);
            printf("  1=%lu 2=%lu m=%lu\n", info.num_1block, info.num_2block, info.max_block);
        }
    
        // free space on flash
        {
            DWORD nclst;
            FATFS *fatfs;
            f_getfree("0:", &nclst, &fatfs);
            printf("LFS free: %u bytes\n", (uint)(nclst * fatfs->csize * 512));
        }
    
        return py_const_none;
    }
    
    py_obj_t pyb_usart_send(py_obj_t data) {
        usart_tx_char(py_obj_get_int(data));
        return py_const_none;
    }
    
    py_obj_t pyb_usart_receive(void) {
        return py_obj_new_int(usart_rx_char());
    }
    
    py_obj_t pyb_usart_status(void) {
        if (usart_rx_any()) {
            return py_const_true;
        } else {
            return py_const_false;
        }
    }
    
    char *strdup(const char *str) {
        uint32_t len = strlen(str);
        char *s2 = m_new(char, len + 1);
        memcpy(s2, str, len);
        s2[len] = 0;
        return s2;
    }
    
    #define READLINE_HIST_SIZE (8)
    
    static const char *readline_hist[READLINE_HIST_SIZE] = {NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL};
    
    void stdout_tx_str(const char *str) {
        usart_tx_str(str);
        usb_vcp_send_str(str);
    }
    
    int readline(vstr_t *line, const char *prompt) {
        stdout_tx_str(prompt);
        int len = vstr_len(line);
        int escape = 0;
        int hist_num = 0;
        for (;;) {
            char c;
            for (;;) {
                if (usb_vcp_rx_any() != 0) {
                    c = usb_vcp_rx_get();
                    break;
                } else if (usart_rx_any()) {
                    c = usart_rx_char();
                    break;
                }
                sys_tick_delay_ms(1);
            }
            if (escape == 0) {
                if (c == 4 && vstr_len(line) == len) {
                    return 0;
                } else if (c == '\r') {
                    stdout_tx_str("\r\n");
                    for (int i = READLINE_HIST_SIZE - 1; i > 0; i--) {
                        readline_hist[i] = readline_hist[i - 1];
                    }
                    readline_hist[0] = strdup(vstr_str(line));
                    return 1;
                } else if (c == 27) {
                    escape = true;
                } else if (c == 127) {
                    if (vstr_len(line) > len) {
                        vstr_cut_tail(line, 1);
                        stdout_tx_str("\b \b");
                    }
                } else if (32 <= c && c <= 126) {
                    vstr_add_char(line, c);
                    stdout_tx_str(line->buf + line->len - 1);
                }
            } else if (escape == 1) {
                if (c == '[') {
                    escape = 2;
                } else {
                    escape = 0;
                }
            } else if (escape == 2) {
                escape = 0;
                if (c == 'A') {
                    // up arrow
                    if (hist_num < READLINE_HIST_SIZE && readline_hist[hist_num] != NULL) {
                        // erase line
                        for (int i = line->len - len; i > 0; i--) {
                            stdout_tx_str("\b \b");
                        }
                        // set line to history
                        line->len = len;
                        vstr_add_str(line, readline_hist[hist_num]);
                        // draw line
                        stdout_tx_str(readline_hist[hist_num]);
                        // increase hist num
                        hist_num += 1;
                    }
                }
            } else {
                escape = 0;
            }
            sys_tick_delay_ms(10);
        }
    }
    
    void do_repl(void) {
        stdout_tx_str("Micro Python 0.5; STM32F405RG; PYBv2\r\n");
        stdout_tx_str("Type \"help\" for more information.\r\n");
    
        vstr_t line;
        vstr_init(&line);
    
        for (;;) {
            vstr_reset(&line);
            int ret = readline(&line, ">>> ");
            if (ret == 0) {
                // EOF
                break;
            }
    
            if (vstr_len(&line) == 0) {
                continue;
            }
    
            if (py_repl_is_compound_stmt(vstr_str(&line))) {
                for (;;) {
                    vstr_add_char(&line, '\n');
                    int len = vstr_len(&line);
                    int ret = readline(&line, "... ");
                    if (ret == 0 || vstr_len(&line) == len) {
                        // done entering compound statement
                        break;
                    }
                }
            }
    
            py_lexer_str_buf_t sb;
            py_lexer_t *lex = py_lexer_new_from_str_len("<stdin>", vstr_str(&line), vstr_len(&line), false, &sb);
            py_parse_node_t pn = py_parse(lex, PY_PARSE_SINGLE_INPUT);
            py_lexer_free(lex);
    
            if (pn != PY_PARSE_NODE_NULL) {
                bool comp_ok = py_compile(pn, true);
                if (comp_ok) {
                    py_obj_t module_fun = rt_make_function_from_id(1);
                    if (module_fun != py_const_none) {
                        nlr_buf_t nlr;
                        if (nlr_push(&nlr) == 0) {
                            rt_call_function_0(module_fun);
                            nlr_pop();
                        } else {
                            // uncaught exception
                            py_obj_print((py_obj_t)nlr.ret_val);
                            printf("\n");
                        }
                    }
                }
            }
        }
    
        stdout_tx_str("\r\n");
    }
    
    bool do_file(const char *filename) {
        py_lexer_file_buf_t fb;
        py_lexer_t *lex = py_lexer_new_from_file(filename, &fb);
    
        if (lex == NULL) {
            printf("could not open file '%s' for reading\n", filename);
            return false;
        }
    
        py_parse_node_t pn = py_parse(lex, PY_PARSE_FILE_INPUT);
        py_lexer_free(lex);
    
        if (pn == PY_PARSE_NODE_NULL) {
            return false;
        }
    
        bool comp_ok = py_compile(pn, false);
        if (!comp_ok) {
            return false;
        }
    
        py_obj_t module_fun = rt_make_function_from_id(1);
        if (module_fun == py_const_none) {
            return false;
        }
    
        nlr_buf_t nlr;
        if (nlr_push(&nlr) == 0) {
            rt_call_function_0(module_fun);
            nlr_pop();
            return true;
        } else {
            // uncaught exception
            py_obj_print((py_obj_t)nlr.ret_val);
            printf("\n");
            return false;
        }
    }
    
    #define RAM_START (0x20000000) // fixed for chip
    #define HEAP_END  (0x2001c000) // tunable
    #define RAM_END   (0x20020000) // fixed for chip
    
    void gc_helper_get_regs_and_clean_stack(machine_uint_t *regs, machine_uint_t heap_end);
    
    void gc_collect(void) {
        uint32_t start = sys_tick_counter;
        gc_collect_start();
        gc_collect_root((void**)RAM_START, (((uint32_t)&_heap_start) - RAM_START) / 4);
        machine_uint_t regs[10];
        gc_helper_get_regs_and_clean_stack(regs, HEAP_END);
        gc_collect_root((void**)HEAP_END, (RAM_END - HEAP_END) / 4); // will trace regs since they now live in this function on the stack
        gc_collect_end();
        uint32_t ticks = sys_tick_counter - start; // TODO implement a function that does this properly
        gc_info_t info;
        gc_info(&info);
        printf("GC@%lu %lums\n", start, ticks);
        printf(" %lu total\n", info.total);
        printf(" %lu : %lu\n", info.used, info.free);
        printf(" 1=%lu 2=%lu m=%lu\n", info.num_1block, info.num_2block, info.max_block);
    }
    
    py_obj_t pyb_gc(void) {
        gc_collect();
        return py_const_none;
    }
    
    // PWM
    // TIM2 and TIM5 have CH1, CH2, CH3, CH4 on PA0-PA3 respectively
    // they are both 32-bit counters
    // 16-bit prescaler
    // TIM2_CH3 also on PB10 (used below)
    void servo_init(void) {
        // TIM2 clock enable
        RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
    
        // GPIOC Configuration: TIM2_CH3 (PB10)
        GPIO_InitTypeDef GPIO_InitStructure;
        GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
        GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
        GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;
        GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
        GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
        GPIO_Init(GPIOB, &GPIO_InitStructure);
    
        // Connect TIM2 pins to AF1
        GPIO_PinAFConfig(GPIOB, GPIO_PinSource10, GPIO_AF_TIM2);
    
        // Compute the prescaler value so TIM2 runs at 100kHz
        uint16_t PrescalerValue = (uint16_t) ((SystemCoreClock / 2) / 100000) - 1;
    
        // Time base configuration
        TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
        TIM_TimeBaseStructure.TIM_Period = 2000; // timer cycles at 50Hz
        TIM_TimeBaseStructure.TIM_Prescaler = PrescalerValue;
        TIM_TimeBaseStructure.TIM_ClockDivision = 0;
        TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
        TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
    
        // PWM1 Mode configuration: Channel1
        TIM_OCInitTypeDef TIM_OCInitStructure;
        TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
        TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
        TIM_OCInitStructure.TIM_Pulse = 150; // units of 10us
        TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
        TIM_OC3Init(TIM2, &TIM_OCInitStructure);
    
        // ?
        TIM_OC3PreloadConfig(TIM2, TIM_OCPreload_Enable);
    
        // ?
        TIM_ARRPreloadConfig(TIM2, ENABLE);
    
        // TIM2 enable counter
        TIM_Cmd(TIM2, ENABLE);
    }
    
    py_obj_t pyb_servo_set(py_obj_t value) {
        int v = py_obj_get_int(value);
        if (v < 100) { v = 100; }
        if (v > 200) { v = 200; }
        TIM2->CCR3 = v;
        return py_const_none;
    }
    
    py_obj_t pyb_pwm_set(py_obj_t period, py_obj_t pulse) {
        int pe = py_obj_get_int(period);
        int pu = py_obj_get_int(pulse);
        TIM2->ARR = pe;
        TIM2->CCR3 = pu;
        return py_const_none;
    }
    
    #define MMA_ADDR (0x4c)
    
    py_obj_t pyb_mma_read(void) {
        mma_start(MMA_ADDR, 1);
        mma_send_byte(0);
        mma_restart(MMA_ADDR, 0);
        py_obj_t data[4];
        for (int i = 3; i >= 1; i--) {
            int v = mma_read_ack() & 0x3f;
            if (v & 0x20) {
                v |= ~0x1f;
            }
            data[i] = py_obj_new_int(v);
        }
        data[0] = py_obj_new_int(mma_read_nack());
        return rt_build_tuple(4, data); // items in reverse order in data
    }
    
    py_obj_t pyb_hid_send_report(py_obj_t arg) {
        py_obj_t *items = py_obj_get_array_fixed_n(arg, 4);
        uint8_t data[4];
        data[0] = py_obj_get_int(items[0]);
        data[1] = py_obj_get_int(items[1]);
        data[2] = py_obj_get_int(items[2]);
        data[3] = py_obj_get_int(items[3]);
        usb_hid_send_report(data);
        return py_const_none;
    }
    
    static void rtc_init(void) {
        /* Enable the PWR clock */
        RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);
    
        /* Allow access to RTC */
        PWR_BackupAccessCmd(ENABLE);
    
        /* Enable the LSE OSC */
        RCC_LSEConfig(RCC_LSE_ON);
    
        /* Wait till LSE is ready */
        while(RCC_GetFlagStatus(RCC_FLAG_LSERDY) == RESET) {
        }
    
        /* Select the RTC Clock Source */
        RCC_RTCCLKConfig(RCC_RTCCLKSource_LSE);
        /* ck_spre(1Hz) = RTCCLK(LSE) /(uwAsynchPrediv + 1)*(uwSynchPrediv + 1)*/
        uint32_t uwSynchPrediv = 0xFF;
        uint32_t uwAsynchPrediv = 0x7F;
    
        /* Enable the RTC Clock */
        RCC_RTCCLKCmd(ENABLE);
    
        /* Wait for RTC APB registers synchronisation */
        RTC_WaitForSynchro();
    
        /* Configure the RTC data register and RTC prescaler */
        RTC_InitTypeDef RTC_InitStructure;
        RTC_InitStructure.RTC_AsynchPrediv = uwAsynchPrediv;
        RTC_InitStructure.RTC_SynchPrediv = uwSynchPrediv;
        RTC_InitStructure.RTC_HourFormat = RTC_HourFormat_24;
        RTC_Init(&RTC_InitStructure);
    
        // Set the date (BCD)
        RTC_DateTypeDef RTC_DateStructure;
        RTC_DateStructure.RTC_Year = 0x13;
        RTC_DateStructure.RTC_Month = RTC_Month_October;
        RTC_DateStructure.RTC_Date = 0x26;
        RTC_DateStructure.RTC_WeekDay = RTC_Weekday_Saturday;
        RTC_SetDate(RTC_Format_BCD, &RTC_DateStructure);
    
        // Set the time (BCD)
        RTC_TimeTypeDef RTC_TimeStructure;
        RTC_TimeStructure.RTC_H12     = RTC_H12_AM;
        RTC_TimeStructure.RTC_Hours   = 0x01;
        RTC_TimeStructure.RTC_Minutes = 0x53;
        RTC_TimeStructure.RTC_Seconds = 0x00;
        RTC_SetTime(RTC_Format_BCD, &RTC_TimeStructure);
    
        // Indicator for the RTC configuration
        //RTC_WriteBackupRegister(RTC_BKP_DR0, 0x32F2);
    }
    
    py_obj_t pyb_rtc_read(void) {
        RTC_TimeTypeDef RTC_TimeStructure;
        RTC_GetTime(RTC_Format_BIN, &RTC_TimeStructure);
        printf("%02d:%02d:%02d\n", RTC_TimeStructure.RTC_Hours, RTC_TimeStructure.RTC_Minutes, RTC_TimeStructure.RTC_Seconds);
        return py_const_none;
    }
    
    py_obj_t pyb_lcd8(py_obj_t pos, py_obj_t val) {
        int pos_val = py_obj_get_int(pos);
        int val_val = py_obj_get_int(val);
        lcd_draw_pixel_8(pos_val, val_val);
        return py_const_none;
    }
    
    void file_obj_print(py_obj_t o) {
        FIL *fp;
        py_user_get_data(o, (machine_uint_t*)&fp, NULL);
        printf("<file %p>", fp);
    }
    
    py_obj_t file_obj_read(py_obj_t self, py_obj_t arg) {
        FIL *fp;
        py_user_get_data(self, (machine_uint_t*)&fp, NULL);
        int n = py_obj_get_int(arg);
        char *buf = m_new(char, n + 1);
        UINT n_out;
        f_read(fp, buf, n, &n_out);
        buf[n_out] = 0;
        return py_obj_new_str(qstr_from_str_take(buf));
    }
    
    py_obj_t file_obj_write(py_obj_t self, py_obj_t arg) {
        FIL *fp;
        py_user_get_data(self, (machine_uint_t*)&fp, NULL);
        const char *s = qstr_str(py_obj_get_qstr(arg));
        UINT n_out;
        FRESULT res = f_write(fp, s, strlen(s), &n_out);
        if (res != FR_OK) {
            printf("File error: could not write to file; error code %d\n", res);
        } else if (n_out != strlen(s)) {
            printf("File error: could not write all data to file; wrote %d / %d bytes\n", n_out, strlen(s));
        }
        return py_const_none;
    }
    
    py_obj_t file_obj_close(py_obj_t self) {
        FIL *fp;
        py_user_get_data(self, (machine_uint_t*)&fp, NULL);
        f_close(fp);
        return py_const_none;
    }
    
    // TODO gc hook to close the file if not already closed
    const py_user_info_t file_obj_info = {
        "File",
        file_obj_print,
        {
            {"read", 1, file_obj_read},
            {"write", 1, file_obj_write},
            {"close", 0, file_obj_close},
            {NULL, 0, NULL},
        }
    };
    
    py_obj_t pyb_io_open(py_obj_t o_filename, py_obj_t o_mode) {
        const char *filename = qstr_str(py_obj_get_qstr(o_filename));
        const char *mode = qstr_str(py_obj_get_qstr(o_mode));
        FIL *fp = m_new(FIL, 1);
        if (mode[0] == 'r') {
            // open for reading
            FRESULT res = f_open(fp, filename, FA_READ);
            if (res != FR_OK) {
                printf("FileNotFoundError: [Errno 2] No such file or directory: '%s'\n", filename);
                return py_const_none;
            }
        } else if (mode[0] == 'w') {
            // open for writing, truncate the file first
            FRESULT res = f_open(fp, filename, FA_WRITE | FA_CREATE_ALWAYS);
            if (res != FR_OK) {
                printf("?FileError: could not create file: '%s'\n", filename);
                return py_const_none;
            }
        } else {
            printf("ValueError: invalid mode: '%s'\n", mode);
            return py_const_none;
        }
        return py_obj_new_user(&file_obj_info, (machine_uint_t)fp, 0);
    }
    
    int main(void) {
        // TODO disable JTAG
    
        // set interrupt priority config to use all 4 bits for pre-empting
        NVIC_PriorityGroupConfig(NVIC_PriorityGroup_4);
    
        // enable the CCM RAM and the GPIO's
        RCC->AHB1ENR |= RCC_AHB1ENR_CCMDATARAMEN | RCC_AHB1ENR_GPIOAEN | RCC_AHB1ENR_GPIOBEN | RCC_AHB1ENR_GPIOCEN;
    
        // configure SDIO pins to be high to start with (apparently makes it more robust)
        {
          GPIO_InitTypeDef GPIO_InitStructure;
          GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9 | GPIO_Pin_10 | GPIO_Pin_11 | GPIO_Pin_12;
          GPIO_InitStructure.GPIO_Speed = GPIO_Speed_25MHz;
          GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
          GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
          GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
          GPIO_Init(GPIOC, &GPIO_InitStructure);
    
          // Configure PD.02 CMD line
          GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;
          GPIO_Init(GPIOD, &GPIO_InitStructure);
        }
    
        // basic sub-system init
        sys_tick_init();
        led_init();
        rtc_init();
    
        // turn on LED to indicate bootup
        led_state(PYB_LED_G1, 1);
    
        // more sub-system init
        sw_init();
        storage_init();
        usart_init();
    
        int first_soft_reset = true;
    
    soft_reset:
    
        // LCD init
        lcd_init();
    
        // GC init
        gc_init(&_heap_start, (void*)HEAP_END);
    
        // Micro Python init
        qstr_init();
        rt_init();
    
        // servo
        servo_init();
    
        // audio
        audio_init();
    
        // timer
        timer_init();
    
        // add some functions to the python namespace
        {
            py_obj_t m = py_module_new();
            rt_store_attr(m, qstr_from_str_static("info"), rt_make_function_0(pyb_info));
            rt_store_attr(m, qstr_from_str_static("source_dir"), rt_make_function_1(pyb_source_dir));
            rt_store_attr(m, qstr_from_str_static("main"), rt_make_function_1(pyb_main));
            rt_store_attr(m, qstr_from_str_static("sync"), rt_make_function_0(pyb_sync));
            rt_store_attr(m, qstr_from_str_static("gc"), rt_make_function_0(pyb_gc));
            rt_store_attr(m, qstr_from_str_static("delay"), rt_make_function_1(pyb_delay));
            rt_store_attr(m, qstr_from_str_static("led"), rt_make_function_1(pyb_led));
            rt_store_attr(m, qstr_from_str_static("sw"), rt_make_function_0(pyb_sw));
            rt_store_attr(m, qstr_from_str_static("servo"), rt_make_function_1(pyb_servo_set));
            rt_store_attr(m, qstr_from_str_static("pwm"), rt_make_function_2(pyb_pwm_set));
            rt_store_attr(m, qstr_from_str_static("mma"), rt_make_function_0(pyb_mma_read));
            rt_store_attr(m, qstr_from_str_static("hid"), rt_make_function_1(pyb_hid_send_report));
            rt_store_attr(m, qstr_from_str_static("time"), rt_make_function_0(pyb_rtc_read));
            rt_store_attr(m, qstr_from_str_static("uout"), rt_make_function_1(pyb_usart_send));
            rt_store_attr(m, qstr_from_str_static("uin"), rt_make_function_0(pyb_usart_receive));
            rt_store_attr(m, qstr_from_str_static("ustat"), rt_make_function_0(pyb_usart_status));
            rt_store_attr(m, qstr_from_str_static("lcd8"), rt_make_function_2(pyb_lcd8));
            rt_store_name(qstr_from_str_static("pyb"), m);
    
            rt_store_name(qstr_from_str_static("open"), rt_make_function_2(pyb_io_open));
        }
    
        // print a message to the LCD
        lcd_print_str(" micro py board\n");
    
        // local filesystem init
        {
            // try to mount the flash
            FRESULT res = f_mount(&fatfs0, "0:", 1);
            if (res == FR_OK) {
                // mount sucessful
            } else if (res == FR_NO_FILESYSTEM) {
                // no filesystem, so create a fresh one
    
                // LED on to indicate creation of LFS
                led_state(PYB_LED_R2, 1);
                uint32_t stc = sys_tick_counter;
    
                res = f_mkfs("0:", 0, 0);
                if (res == FR_OK) {
                    // success creating fresh LFS
                } else {
                    __fatal_error("could not create LFS");
                }
    
                // keep LED on for at least 200ms
                sys_tick_wait_at_least(stc, 200);
                led_state(PYB_LED_R2, 0);
            } else {
                __fatal_error("could not access LFS");
            }
        }
    
        // make sure we have a /boot.py
        {
            FILINFO fno;
            FRESULT res = f_stat("0:/boot.py", &fno);
            if (res == FR_OK) {
                if (fno.fattrib & AM_DIR) {
                    // exists as a directory
                    // TODO handle this case
                    // see http://elm-chan.org/fsw/ff/img/app2.c for a "rm -rf" implementation
                } else {
                    // exists as a file, good!
                }
            } else {
                // doesn't exist, create fresh file
    
                // LED on to indicate creation of boot.py
                led_state(PYB_LED_R2, 1);
                uint32_t stc = sys_tick_counter;
    
                FIL fp;
                f_open(&fp, "0:/boot.py", FA_WRITE | FA_CREATE_ALWAYS);
                UINT n;
                f_write(&fp, fresh_boot_py, sizeof(fresh_boot_py) - 1 /* don't count null terminator */, &n);
                // TODO check we could write n bytes
                f_close(&fp);
    
                // keep LED on for at least 200ms
                sys_tick_wait_at_least(stc, 200);
                led_state(PYB_LED_R2, 0);
            }
        }
    
        // run /boot.py
        if (!do_file("0:/boot.py")) {
            flash_error(4);
        }
    
        // USB
        usb_init();
    
        // MMA
        if (first_soft_reset) {
            // init and reset address to zero
            mma_init();
            mma_start(MMA_ADDR, 1);
            mma_send_byte(0);
            mma_stop();
    
            /*
            // read and print all 11 registers
            mma_start(MMA_ADDR, 1);
            mma_send_byte(0);
            mma_restart(MMA_ADDR, 0);
            for (int i = 0; i <= 0xa; i++) {
                int data;
                if (i == 0xa) {
                    data = mma_read_nack();
                } else {
                    data = mma_read_ack();
                }
                printf(" %02x", data);
            }
            printf("\n");
            */
    
            // put into active mode
            mma_start(MMA_ADDR, 1);
            mma_send_byte(7); // mode
            mma_send_byte(1); // active mode
            mma_stop();
    
            /*
            // infinite loop to read values
            for (;;) {
                sys_tick_delay_ms(500);
    
                mma_start(MMA_ADDR, 1);
                mma_send_byte(0);
                mma_restart(MMA_ADDR, 0);
                for (int i = 0; i <= 3; i++) {
                    int data;
                    if (i == 3) {
                        data = mma_read_nack();
                        printf(" %02x\n", data);
                    } else {
                        data = mma_read_ack() & 0x3f;
                        if (data & 0x20) {
                            data |= ~0x1f;
                        }
                        printf(" % 2d", data);
                    }
                }
            }
            */
        }
    
        // turn boot-up LED off
        led_state(PYB_LED_G1, 0);
    
        // run main script
        {
            vstr_t *vstr = vstr_new();
            vstr_add_str(vstr, "0:/");
            if (pyb_config_source_dir == 0) {
                vstr_add_str(vstr, "src");
            } else {
                vstr_add_str(vstr, qstr_str(pyb_config_source_dir));
            }
            vstr_add_char(vstr, '/');
            if (pyb_config_main == 0) {
                vstr_add_str(vstr, "main.py");
            } else {
                vstr_add_str(vstr, qstr_str(pyb_config_main));
            }
            if (!do_file(vstr_str(vstr))) {
                flash_error(3);
            }
            vstr_free(vstr);
        }
    
        //printf("init;al=%u\n", m_get_total_bytes_allocated()); // 1600, due to qstr_init
        //sys_tick_delay_ms(1000);
    
        // Python!
        if (0) {
            //const char *pysrc = "def f():\n  x=x+1\nprint(42)\n";
            const char *pysrc =
                // impl01.py
                /*
                "x = 0\n"
                "while x < 400:\n"
                "    y = 0\n"
                "    while y < 400:\n"
                "        z = 0\n"
                "        while z < 400:\n"
                "            z = z + 1\n"
                "        y = y + 1\n"
                "    x = x + 1\n";
                */
                // impl02.py
                /*
                "#@micropython.native\n"
                "def f():\n"
                "    x = 0\n"
                "    while x < 400:\n"
                "        y = 0\n"
                "        while y < 400:\n"
                "            z = 0\n"
                "            while z < 400:\n"
                "                z = z + 1\n"
                "            y = y + 1\n"
                "        x = x + 1\n"
                "f()\n";
                */
                /*
                "print('in python!')\n"
                "x = 0\n"
                "while x < 4:\n"
                "    pyb_led(True)\n"
                "    pyb_delay(201)\n"
                "    pyb_led(False)\n"
                "    pyb_delay(201)\n"
                "    x += 1\n"
                "print('press me!')\n"
                "while True:\n"
                "    pyb_led(pyb_sw())\n";
                */
                /*
                // impl16.py
                "@micropython.asm_thumb\n"
                "def delay(r0):\n"
                "    b(loop_entry)\n"
                "    label(loop1)\n"
                "    movw(r1, 55999)\n"
                "    label(loop2)\n"
                "    subs(r1, r1, 1)\n"
                "    cmp(r1, 0)\n"
                "    bgt(loop2)\n"
                "    subs(r0, r0, 1)\n"
                "    label(loop_entry)\n"
                "    cmp(r0, 0)\n"
                "    bgt(loop1)\n"
                "print('in python!')\n"
                "@micropython.native\n"
                "def flash(n):\n"
                "    x = 0\n"
                "    while x < n:\n"
                "        pyb_led(True)\n"
                "        delay(249)\n"
                "        pyb_led(False)\n"
                "        delay(249)\n"
                "        x = x + 1\n"
                "flash(20)\n";
                */
                // impl18.py
                /*
                "# basic exceptions\n"
                "x = 1\n"
                "try:\n"
                "    x.a()\n"
                "except:\n"
                "    print(x)\n";
                */
                // impl19.py
                "# for loop\n"
                "def f():\n"
                "    for x in range(400):\n"
                "        for y in range(400):\n"
                "            for z in range(400):\n"
                "                pass\n"
                "f()\n";
    
            py_lexer_str_buf_t py_lexer_str_buf;
            py_lexer_t *lex = py_lexer_new_from_str_len("<stdin>", pysrc, strlen(pysrc), false, &py_lexer_str_buf);
    
            // nalloc=1740;6340;6836 -> 140;4600;496 bytes for lexer, parser, compiler
            printf("lex; al=%u\n", m_get_total_bytes_allocated());
            sys_tick_delay_ms(1000);
            py_parse_node_t pn = py_parse(lex, PY_PARSE_FILE_INPUT);
            py_lexer_free(lex);
            if (pn != PY_PARSE_NODE_NULL) {
                printf("pars;al=%u\n", m_get_total_bytes_allocated());
                sys_tick_delay_ms(1000);
                //parse_node_show(pn, 0);
                bool comp_ok = py_compile(pn, false);
                printf("comp;al=%u\n", m_get_total_bytes_allocated());
                sys_tick_delay_ms(1000);
    
                if (!comp_ok) {
                    printf("compile error\n");
                } else {
                    // execute it!
    
                    py_obj_t module_fun = rt_make_function_from_id(1);
    
                    // flash once
                    led_state(PYB_LED_G1, 1);
                    sys_tick_delay_ms(100);
                    led_state(PYB_LED_G1, 0);
    
                    nlr_buf_t nlr;
                    if (nlr_push(&nlr) == 0) {
                        py_obj_t ret = rt_call_function_0(module_fun);
                        printf("done! got: ");
                        py_obj_print(ret);
                        printf("\n");
                        nlr_pop();
                    } else {
                        // uncaught exception
                        printf("exception: ");
                        py_obj_print((py_obj_t)nlr.ret_val);
                        printf("\n");
                    }
    
                    // flash once
                    led_state(PYB_LED_G1, 1);
                    sys_tick_delay_ms(100);
                    led_state(PYB_LED_G1, 0);
    
                    sys_tick_delay_ms(1000);
                    printf("nalloc=%u\n", m_get_total_bytes_allocated());
                    sys_tick_delay_ms(1000);
                }
            }
        }
    
        // HID example
        if (0) {
            uint8_t data[4];
            data[0] = 0;
            data[1] = 1;
            data[2] = -2;
            data[3] = 0;
            for (;;) {
                if (sw_get()) {
                    data[0] = 0x01; // 0x04 is middle, 0x02 is right
                } else {
                    data[0] = 0x00;
                }
                mma_start(MMA_ADDR, 1);
                mma_send_byte(0);
                mma_restart(MMA_ADDR, 0);
                for (int i = 0; i <= 1; i++) {
                    int v = mma_read_ack() & 0x3f;
                    if (v & 0x20) {
                        v |= ~0x1f;
                    }
                    data[1 + i] = v;
                }
                mma_read_nack();
                usb_hid_send_report(data);
                sys_tick_delay_ms(15);
            }
        }
    
        do_repl();
    
        // benchmark C version of impl02.py
        if (0) {
            led_state(PYB_LED_G1, 1);
            sys_tick_delay_ms(100);
            led_state(PYB_LED_G1, 0);
            impl02_c_version();
            led_state(PYB_LED_G1, 1);
            sys_tick_delay_ms(100);
            led_state(PYB_LED_G1, 0);
        }
    
        // SD card testing
        if (1) {
            extern void sdio_init(void);
            sdio_init();
        }
    
        printf("PYB: sync filesystems\n");
        pyb_sync();
    
        printf("PYB: soft reboot\n");
    
        first_soft_reset = false;
        goto soft_reset;
    }
    
    double __aeabi_f2d(float x) {
        // TODO
        return 0.0;
    }
    
    float __aeabi_d2f(double x) {
        // TODO
        return 0.0;
    }
    
    double sqrt(double x) {
        // TODO
        return 0.0;
    }