codal_port/mphalport.h: Add defines for C-level pin API.

So that machine.time_pulse_us() works (prior to this commit it was using
the virtual-pin API and not working).

Signed-off-by: Damien George <[email protected]>

Author: dpgeorge

src/codal_port/modmicrobit.h

@@ -191,6 +191,7 @@ extern const struct _microbit_button_obj_t microbit_button_a_obj;
 extern const struct _microbit_button_obj_t microbit_button_b_obj;
 
 const microbit_pin_obj_t *microbit_obj_get_pin(mp_const_obj_t o);
+uint8_t microbit_obj_get_pin_name(mp_obj_t o);
 
 // Release pin for use by other modes. Safe to call in an interrupt.
 // If pin is NULL or pin already unused, then this is a no-op

src/codal_port/mphalport.h

@@ -30,3 +30,9 @@
 #define mp_hal_ticks_cpu() (0)
 
 void mp_hal_set_interrupt_char(int c);
+
+// MicroPython low-level C API for pins
+#include "modmicrobit.h"
+#define mp_hal_pin_obj_t uint8_t
+#define mp_hal_get_pin_obj(obj) microbit_obj_get_pin_name(obj)
+#define mp_hal_pin_read(pin) microbit_hal_pin_read(pin)