From eaef6b5324fa2ff425802d4abeea45aa945bfc14 Mon Sep 17 00:00:00 2001
From: Radomir Dopieralski <openstack@sheep.art.pl>
Date: Sat, 8 Oct 2016 17:34:46 +0200
Subject: [PATCH] extmod/machine_i2c: Use writes not reads in i2c.scan().
As per discussion in #2449, using write requests instead of read requests
for I2C.scan() seems to support a larger number of devices, especially
ones that are write-only. Even a read-only I2C device has to implement
writes in order to be able to receive the address of the register to read.
---
extmod/machine_i2c.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/extmod/machine_i2c.c b/extmod/machine_i2c.c
index d76e5eedd..e201b2399 100644
--- a/extmod/machine_i2c.c
+++ b/extmod/machine_i2c.c
@@ -272,7 +272,7 @@ STATIC mp_obj_t machine_i2c_scan(mp_obj_t self_in) {
// 7-bit addresses 0b0000xxx and 0b1111xxx are reserved
for (int addr = 0x08; addr < 0x78; ++addr) {
mp_hal_i2c_start(self);
- int ack = mp_hal_i2c_write_byte(self, (addr << 1) | 1);
+ int ack = mp_hal_i2c_write_byte(self, (addr << 1));
if (ack) {
mp_obj_list_append(list, MP_OBJ_NEW_SMALL_INT(addr));
}
--
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