diff options
| author | Damien George <damien.p.george@gmail.com> | 2019-01-22 00:23:51 +1100 |
|---|---|---|
| committer | Damien George <damien.p.george@gmail.com> | 2019-01-22 00:26:04 +1100 |
| commit | 18d3a5df260b1e85c3fd2718acbaeac199a33acf (patch) | |
| tree | 633cba85f10edb05beda5fe319c127b475c1bf7f | |
| parent | f102ac54e95ca23f266aea30f3de7fd9a39b18a3 (diff) | |
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.
| -rw-r--r-- | ports/esp8266/esp_mphal.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/ports/esp8266/esp_mphal.h b/ports/esp8266/esp_mphal.h index 56d9fa35f..8712a2a33 100644 --- a/ports/esp8266/esp_mphal.h +++ b/ports/esp8266/esp_mphal.h @@ -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)) |