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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.
pull/1/head
Damien George 2018-03-12 12:45:09 +11:00
parent 4d3a92c67c
commit 033c32e694
1 changed files with 1 additions and 1 deletions
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2
ports/esp8266/esp_mphal.h
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@ -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))