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esp8266/esp_mphal: Provide mp_hal_pin_od_high_dht so DHT works reliably. 

The original behaviour of open-drain-high was to use the open-drain mode of
the GPIO pin, and this seems to make driving a DHT more reliable.  See
issue #4233.
This commit is contained in:
Damien George 2019-01-22 00:23:51 +11:00
parent f102ac54e9
commit 18d3a5df26
1 changed files with 5 additions and 0 deletions
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5
ports/esp8266/esp_mphal.h
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@ -91,6 +91,11 @@ void mp_hal_pin_open_drain(mp_hal_pin_obj_t pin);
if ((p) == 16) { WRITE_PERI_REG(RTC_GPIO_ENABLE, (READ_PERI_REG(RTC_GPIO_ENABLE) & ~1)); } \
else { gpio_output_set(0, 0, 0, 1 << (p)); /* set as input to avoid glitches */ } \
} while (0)
// The DHT driver requires using the open-drain feature of the GPIO to get it to work reliably
#define mp_hal_pin_od_high_dht(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); } \
} while (0)
#define mp_hal_pin_read(p) pin_get(p)
#define mp_hal_pin_write(p, v) pin_set((p), (v))