diff --git a/stm/lcd.c b/stm/lcd.c
index ee4f4da4e0431e54de841db066a00ee65ccaa350..28064c24bf0dcde779ff75e5bed7fc00af17a76b 100644
--- a/stm/lcd.c
+++ b/stm/lcd.c
@@ -1,10 +1,16 @@
 #include <string.h>
 #include <stm32f4xx_gpio.h>
 
+#include "nlr.h"
 #include "misc.h"
+#include "mpyconfig.h"
+#include "parse.h"
+#include "compile.h"
+#include "runtime.h"
+
 #include "systick.h"
-#include "lcd.h"
 #include "font_petme128_8x8.h"
+#include "lcd.h"
 
 #define PYB_LCD_PORT        (GPIOA)
 #define PYB_LCD_CS1_PIN     (GPIO_Pin_0)
@@ -80,14 +86,83 @@ static void lcd_data_out(uint8_t i) {
 }
 */
 
+// writes 8 vertical pixels
+// pos 0 is upper left, pos 1 is 8 pixels to right of that, pos 128 is 8 pixels below that
+py_obj_t lcd_draw_pixel_8(py_obj_t py_pos, py_obj_t py_val) {
+    int pos = py_obj_get_int(py_pos);
+    int val = py_obj_get_int(py_val);
+    int page = pos / 128;
+    int offset = pos - (page * 128);
+    lcd_out(LCD_INSTR, 0xb0 | page); // page address set
+    lcd_out(LCD_INSTR, 0x10 | ((offset >> 4) & 0x0f)); // column address set upper
+    lcd_out(LCD_INSTR, 0x00 | (offset & 0x0f)); // column address set lower
+    lcd_out(LCD_DATA, val); // write data
+    return py_const_none;
+}
+
 #define LCD_BUF_W (16)
 #define LCD_BUF_H (4)
 
-char lcd_buffer[LCD_BUF_W * LCD_BUF_H];
+char lcd_char_buffer[LCD_BUF_W * LCD_BUF_H];
 int lcd_line;
 int lcd_column;
 int lcd_next_line;
 
+#define LCD_PIX_BUF_SIZE (128 * 32 / 8)
+byte lcd_pix_buf[LCD_PIX_BUF_SIZE];
+byte lcd_pix_buf2[LCD_PIX_BUF_SIZE];
+
+py_obj_t lcd_pix_clear(void) {
+    memset(lcd_pix_buf, 0, LCD_PIX_BUF_SIZE);
+    memset(lcd_pix_buf2, 0, LCD_PIX_BUF_SIZE);
+    return py_const_none;
+}
+
+py_obj_t lcd_pix_get(py_obj_t py_x, py_obj_t py_y) {
+    int x = py_obj_get_int(py_x);
+    int y = py_obj_get_int(py_y);
+    if (0 <= x && x <= 127 && 0 <= y && y <= 31) {
+        uint byte_pos = x + 128 * ((uint)y >> 3);
+        if (lcd_pix_buf[byte_pos] & (1 << (y & 7))) {
+            return py_obj_new_int(1);
+        }
+    }
+    return py_obj_new_int(0);
+}
+
+py_obj_t lcd_pix_set(py_obj_t py_x, py_obj_t py_y) {
+    int x = py_obj_get_int(py_x);
+    int y = py_obj_get_int(py_y);
+    if (0 <= x && x <= 127 && 0 <= y && y <= 31) {
+        uint byte_pos = x + 128 * ((uint)y >> 3);
+        lcd_pix_buf2[byte_pos] |= 1 << (y & 7);
+    }
+    return py_const_none;
+}
+
+py_obj_t lcd_pix_reset(py_obj_t py_x, py_obj_t py_y) {
+    int x = py_obj_get_int(py_x);
+    int y = py_obj_get_int(py_y);
+    if (0 <= x && x <= 127 && 0 <= y && y <= 31) {
+        uint byte_pos = x + 128 * ((uint)y >> 3);
+        lcd_pix_buf2[byte_pos] &= ~(1 << (y & 7));
+    }
+    return py_const_none;
+}
+
+py_obj_t lcd_pix_show(void) {
+    memcpy(lcd_pix_buf, lcd_pix_buf2, LCD_PIX_BUF_SIZE);
+    for (uint page = 0; page < 4; page++) {
+        lcd_out(LCD_INSTR, 0xb0 | page); // page address set
+        lcd_out(LCD_INSTR, 0x10); // column address set upper; 0
+        lcd_out(LCD_INSTR, 0x00); // column address set lower; 0
+        for (uint i = 0; i < 128; i++) {
+            lcd_out(LCD_DATA, lcd_pix_buf[i + 128 * page]);
+        }
+    }
+    return py_const_none;
+}
+
 void lcd_init(void) {
     // set the outputs high
     PYB_LCD_PORT->BSRRL = PYB_LCD_CS1_PIN;
@@ -132,11 +207,21 @@ void lcd_init(void) {
     }
 
     for (int i = 0; i < LCD_BUF_H * LCD_BUF_W; i++) {
-        lcd_buffer[i] = ' ';
+        lcd_char_buffer[i] = ' ';
     }
     lcd_line = 0;
     lcd_column = 0;
     lcd_next_line = 0;
+
+    // Python interface
+    py_obj_t m = py_module_new();
+    rt_store_attr(m, qstr_from_str_static("lcd8"), rt_make_function_2(lcd_draw_pixel_8));
+    rt_store_attr(m, qstr_from_str_static("clear"), rt_make_function_0(lcd_pix_clear));
+    rt_store_attr(m, qstr_from_str_static("get"), rt_make_function_2(lcd_pix_get));
+    rt_store_attr(m, qstr_from_str_static("set"), rt_make_function_2(lcd_pix_set));
+    rt_store_attr(m, qstr_from_str_static("reset"), rt_make_function_2(lcd_pix_reset));
+    rt_store_attr(m, qstr_from_str_static("show"), rt_make_function_0(lcd_pix_show));
+    rt_store_name(qstr_from_str_static("lcd"), m);
 }
 
 void lcd_print_str(const char *str) {
@@ -155,10 +240,10 @@ void lcd_print_strn(const char *str, unsigned int len) {
             } else {
                 lcd_line = LCD_BUF_H - 1;
                 for (int i = 0; i < LCD_BUF_W * (LCD_BUF_H - 1); i++) {
-                    lcd_buffer[i] = lcd_buffer[i + LCD_BUF_W];
+                    lcd_char_buffer[i] = lcd_char_buffer[i + LCD_BUF_W];
                 }
                 for (int i = 0; i < LCD_BUF_W; i++) {
-                    lcd_buffer[LCD_BUF_W * (LCD_BUF_H - 1) + i] = ' ';
+                    lcd_char_buffer[LCD_BUF_W * (LCD_BUF_H - 1) + i] = ' ';
                 }
                 redraw_min = 0;
                 redraw_max = LCD_BUF_W * LCD_BUF_H;
@@ -174,7 +259,7 @@ void lcd_print_strn(const char *str, unsigned int len) {
             str -= 1;
             len += 1;
         } else {
-            lcd_buffer[lcd_line * LCD_BUF_W + lcd_column] = *str;
+            lcd_char_buffer[lcd_line * LCD_BUF_W + lcd_column] = *str;
             lcd_column += 1;
             int max = lcd_line * LCD_BUF_W + lcd_column;
             if (max > redraw_max) {
@@ -193,7 +278,7 @@ void lcd_print_strn(const char *str, unsigned int len) {
             lcd_out(LCD_INSTR, 0x00 | (offset & 0x0f)); // column address set lower
             last_page = page;
         }
-        int chr = lcd_buffer[i];
+        int chr = lcd_char_buffer[i];
         if (chr < 32 || chr > 126) {
             chr = 127;
         }
@@ -207,14 +292,3 @@ void lcd_print_strn(const char *str, unsigned int len) {
         sys_tick_delay_ms(200);
     }
 }
-
-// writes 8 vertical pixels
-// pos 0 is upper left, pos 1 is 8 pixels to right of that, pos 128 is 8 pixels below that
-void lcd_draw_pixel_8(int pos, int val) {
-    int page = pos / 128;
-    int offset = pos - (page * 128);
-    lcd_out(LCD_INSTR, 0xb0 | page); // page address set
-    lcd_out(LCD_INSTR, 0x10 | ((offset >> 4) & 0x0f)); // column address set upper
-    lcd_out(LCD_INSTR, 0x00 | (offset & 0x0f)); // column address set lower
-    lcd_out(LCD_DATA, val); // write data
-}
diff --git a/stm/lcd.h b/stm/lcd.h
index 56c541698ea5527859c2c0bf9dea9765b625927b..7b243ee7e302b7d5a6971a8e6a2d8613e34af460 100644
--- a/stm/lcd.h
+++ b/stm/lcd.h
@@ -1,4 +1,3 @@
 void lcd_init(void);
 void lcd_print_str(const char *str);
 void lcd_print_strn(const char *str, unsigned int len);
-void lcd_draw_pixel_8(int pos, int val);
diff --git a/stm/main.c b/stm/main.c
index 4184b389cacaf3216d7ea5c9a017afbdd7e7009f..a1b8e668f03b6edb62013043d0042f3cdfca9427 100644
--- a/stm/main.c
+++ b/stm/main.c
@@ -6,6 +6,7 @@
 #include <stm32f4xx_pwr.h>
 #include <stm32f4xx_rtc.h>
 #include <stm32f4xx_usart.h>
+#include <stm32f4xx_rng.h>
 #include <stm_misc.h>
 #include "std.h"
 
@@ -613,13 +614,6 @@ py_obj_t pyb_rtc_read(void) {
     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);
@@ -695,6 +689,10 @@ py_obj_t pyb_io_open(py_obj_t o_filename, py_obj_t o_mode) {
     return py_obj_new_user(&file_obj_info, (machine_uint_t)fp, 0);
 }
 
+py_obj_t pyb_rng_get(void) {
+    return py_obj_new_int(RNG_GetRandomNumber() >> 16);
+}
+
 int main(void) {
     // TODO disable JTAG
 
@@ -736,9 +734,6 @@ int main(void) {
 
 soft_reset:
 
-    // LCD init
-    lcd_init();
-
     // GC init
     gc_init(&_heap_start, (void*)HEAP_END);
 
@@ -746,6 +741,9 @@ soft_reset:
     qstr_init();
     rt_init();
 
+    // LCD init
+    lcd_init();
+
     // servo
     servo_init();
 
@@ -755,6 +753,12 @@ soft_reset:
     // timer
     timer_init();
 
+    // RNG
+    {
+        RCC_AHB2PeriphClockCmd(RCC_AHB2Periph_RNG, ENABLE);
+        RNG_Cmd(ENABLE);
+    }
+
     // add some functions to the python namespace
     {
         py_obj_t m = py_module_new();
@@ -774,7 +778,7 @@ soft_reset:
         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_attr(m, qstr_from_str_static("rng"), rt_make_function_0(pyb_rng_get));
         rt_store_name(qstr_from_str_static("pyb"), m);
 
         rt_store_name(qstr_from_str_static("open"), rt_make_function_2(pyb_io_open));
@@ -1148,3 +1152,8 @@ double sqrt(double x) {
     // TODO
     return 0.0;
 }
+
+machine_float_t machine_sqrt(machine_float_t x) {
+    // TODO
+    return x;
+}
diff --git a/stm/mpyconfig.h b/stm/mpyconfig.h
index 06a4bd8e022f513bd30eb45a093261fc098fb065..3fa3ac6524ac3e3464493cf49cbb45c30791fbb8 100644
--- a/stm/mpyconfig.h
+++ b/stm/mpyconfig.h
@@ -14,3 +14,5 @@ typedef int32_t machine_int_t; // must be pointer size
 typedef uint32_t machine_uint_t; // must be pointer size
 typedef void *machine_ptr_t; // must be of pointer size
 typedef float machine_float_t;
+
+machine_float_t machine_sqrt(machine_float_t x);