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| author | Damien George <damien.p.george@gmail.com> | 2018-03-12 12:45:09 +1100 |
|---|---|---|
| committer | Damien George <damien.p.george@gmail.com> | 2018-03-12 12:45:09 +1100 |
| commit | 033c32e694199bbb68816883a857a77711d68a13 (patch) | |
| tree | 50dfa8dffad56ffd6c1663e881558c7d3f1f92dc | |
| parent | 4d3a92c67c9b1550eaf07d06ed74de996ee8fa3b (diff) | |
esp8266/esp_mphal.h: Fix I2C glitching by using input mode for od_high.
Certain pins (eg 4 and 5) seem to behave differently at the hardware level
when in open-drain mode: they glitch when set "high" and drive the pin
active high for a brief period before disabling the output driver. To work
around this make the pin an input to let it float high.
| -rw-r--r-- | ports/esp8266/esp_mphal.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/ports/esp8266/esp_mphal.h b/ports/esp8266/esp_mphal.h index 194e56f64..940ca4727 100644 --- a/ports/esp8266/esp_mphal.h +++ b/ports/esp8266/esp_mphal.h @@ -86,7 +86,7 @@ void mp_hal_pin_open_drain(mp_hal_pin_obj_t pin); } while (0) #define mp_hal_pin_od_high(p) do { \ if ((p) == 16) { WRITE_PERI_REG(RTC_GPIO_ENABLE, (READ_PERI_REG(RTC_GPIO_ENABLE) & ~1)); } \ - else { gpio_output_set(1 << (p), 0, 1 << (p), 0); } \ + else { gpio_output_set(0, 0, 0, 1 << (p)); /* set as input to avoid glitches */ } \ } while (0) #define mp_hal_pin_read(p) pin_get(p) #define mp_hal_pin_write(p, v) pin_set((p), (v)) |