implement mp_hal_delay_us() to not need interrupts, and use it

1 files changed, 10 insertions, 12 deletions

diff --git a/shared-module/bitbangio/OneWire.c b/shared-module/bitbangio/OneWire.c
index b226b9d78..f5f479087 100644
--- a/shared-module/bitbangio/OneWire.c
+++ b/shared-module/bitbangio/OneWire.c
@@ -24,8 +24,6 @@
  * THE SOFTWARE.
  */
 
-#include "mphalport.h"
-
 #include "common-hal/microcontroller/Pin.h"
 #include "shared-bindings/bitbangio/OneWire.h"
 #include "shared-bindings/microcontroller/__init__.h"
@@ -51,17 +49,17 @@ void shared_module_bitbangio_onewire_deinit(bitbangio_onewire_obj_t* self) {
     common_hal_digitalio_digitalinout_deinit(&self->pin);
 }
 
-// We can't use common_hal_mcu_delay_us() here because it needs interrupts to be accurate
-// due to SysTick rollover checking, done by an interrupt.
+// We use common_hal_mcu_delay_us(). It should not be dependent on interrupts
+// to do accurate timekeeping, since we disable interrupts during the delays below.
 
 bool shared_module_bitbangio_onewire_reset(bitbangio_onewire_obj_t* self) {
     common_hal_mcu_disable_interrupts();
     common_hal_digitalio_digitalinout_switch_to_output(&self->pin, false, DRIVE_MODE_OPEN_DRAIN);
-    mp_hal_delay_us_loop(480);
+    common_hal_mcu_delay_us(480);
     common_hal_digitalio_digitalinout_switch_to_input(&self->pin, PULL_NONE);
-    mp_hal_delay_us_loop(70);
+    common_hal_mcu_delay_us(70);
     bool value = common_hal_digitalio_digitalinout_get_value(&self->pin);
-    mp_hal_delay_us_loop(410);
+    common_hal_mcu_delay_us(410);
     common_hal_mcu_enable_interrupts();
     return value;
 }
@@ -69,14 +67,14 @@ bool shared_module_bitbangio_onewire_reset(bitbangio_onewire_obj_t* self) {
 bool shared_module_bitbangio_onewire_read_bit(bitbangio_onewire_obj_t* self) {
     common_hal_mcu_disable_interrupts();
     common_hal_digitalio_digitalinout_switch_to_output(&self->pin, false, DRIVE_MODE_OPEN_DRAIN);
-    mp_hal_delay_us_loop(6);
+    common_hal_mcu_delay_us(6);
     common_hal_digitalio_digitalinout_switch_to_input(&self->pin, PULL_NONE);
     // TODO(tannewt): Test with more devices and maybe make the delays
     // configurable. This should be 9 by the datasheet but all bits read as 1
     // then.
-    mp_hal_delay_us_loop(6);
+    common_hal_mcu_delay_us(6);
     bool value = common_hal_digitalio_digitalinout_get_value(&self->pin);
-    mp_hal_delay_us_loop(55);
+    common_hal_mcu_delay_us(55);
     common_hal_mcu_enable_interrupts();
     return value;
 }
@@ -85,8 +83,8 @@ void shared_module_bitbangio_onewire_write_bit(bitbangio_onewire_obj_t* self,
         bool bit) {
     common_hal_mcu_disable_interrupts();
     common_hal_digitalio_digitalinout_switch_to_output(&self->pin, false, DRIVE_MODE_OPEN_DRAIN);
-    mp_hal_delay_us_loop(bit? 6 : 60);
+    common_hal_mcu_delay_us(bit? 6 : 60);
     common_hal_digitalio_digitalinout_switch_to_input(&self->pin, PULL_NONE);
-    mp_hal_delay_us_loop(bit? 64 : 10);
+    common_hal_mcu_delay_us(bit? 64 : 10);
     common_hal_mcu_enable_interrupts();
 }