add circuitpython code

1 files changed, 145 insertions, 0 deletions

diff --git a/circuitpython/extmod/modonewire.c b/circuitpython/extmod/modonewire.c
new file mode 100644
index 0000000..ba7405f
--- /dev/null
+++ b/circuitpython/extmod/modonewire.c
@@ -0,0 +1,145 @@
+// SPDX-FileCopyrightText: 2014 MicroPython & CircuitPython contributors (https://github.com/adafruit/circuitpython/graphs/contributors)
+// SPDX-FileCopyrightText: Copyright (c) 2015-2017 Damien P. George
+//
+// SPDX-License-Identifier: MIT
+
+#include <stdio.h>
+#include <stdint.h>
+
+#include "py/obj.h"
+#include "py/mphal.h"
+
+#if MICROPY_PY_ONEWIRE
+
+/******************************************************************************/
+// Low-level 1-Wire routines
+
+#define TIMING_RESET1 (480)
+#define TIMING_RESET2 (70)
+#define TIMING_RESET3 (410)
+#define TIMING_READ1 (5)
+#define TIMING_READ2 (5)
+#define TIMING_READ3 (40)
+#define TIMING_WRITE1 (10)
+#define TIMING_WRITE2 (50)
+#define TIMING_WRITE3 (10)
+
+STATIC int onewire_bus_reset(mp_hal_pin_obj_t pin) {
+    mp_hal_pin_od_low(pin);
+    mp_hal_delay_us(TIMING_RESET1);
+    uint32_t i = mp_hal_quiet_timing_enter();
+    mp_hal_pin_od_high(pin);
+    mp_hal_delay_us_fast(TIMING_RESET2);
+    int status = !mp_hal_pin_read(pin);
+    mp_hal_quiet_timing_exit(i);
+    mp_hal_delay_us(TIMING_RESET3);
+    return status;
+}
+
+STATIC int onewire_bus_readbit(mp_hal_pin_obj_t pin) {
+    mp_hal_pin_od_high(pin);
+    uint32_t i = mp_hal_quiet_timing_enter();
+    mp_hal_pin_od_low(pin);
+    mp_hal_delay_us_fast(TIMING_READ1);
+    mp_hal_pin_od_high(pin);
+    mp_hal_delay_us_fast(TIMING_READ2);
+    int value = mp_hal_pin_read(pin);
+    mp_hal_quiet_timing_exit(i);
+    mp_hal_delay_us_fast(TIMING_READ3);
+    return value;
+}
+
+STATIC void onewire_bus_writebit(mp_hal_pin_obj_t pin, int value) {
+    uint32_t i = mp_hal_quiet_timing_enter();
+    mp_hal_pin_od_low(pin);
+    mp_hal_delay_us_fast(TIMING_WRITE1);
+    if (value) {
+        mp_hal_pin_od_high(pin);
+    }
+    mp_hal_delay_us_fast(TIMING_WRITE2);
+    mp_hal_pin_od_high(pin);
+    mp_hal_delay_us_fast(TIMING_WRITE3);
+    mp_hal_quiet_timing_exit(i);
+}
+
+/******************************************************************************/
+// MicroPython bindings
+
+STATIC mp_obj_t onewire_reset(mp_obj_t pin_in) {
+    return mp_obj_new_bool(onewire_bus_reset(mp_hal_get_pin_obj(pin_in)));
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(onewire_reset_obj, onewire_reset);
+
+STATIC mp_obj_t onewire_readbit(mp_obj_t pin_in) {
+    return MP_OBJ_NEW_SMALL_INT(onewire_bus_readbit(mp_hal_get_pin_obj(pin_in)));
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(onewire_readbit_obj, onewire_readbit);
+
+STATIC mp_obj_t onewire_readbyte(mp_obj_t pin_in) {
+    mp_hal_pin_obj_t pin = mp_hal_get_pin_obj(pin_in);
+    uint8_t value = 0;
+    for (int i = 0; i < 8; ++i) {
+        value |= onewire_bus_readbit(pin) << i;
+    }
+    return MP_OBJ_NEW_SMALL_INT(value);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(onewire_readbyte_obj, onewire_readbyte);
+
+STATIC mp_obj_t onewire_writebit(mp_obj_t pin_in, mp_obj_t value_in) {
+    onewire_bus_writebit(mp_hal_get_pin_obj(pin_in), mp_obj_get_int(value_in));
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_2(onewire_writebit_obj, onewire_writebit);
+
+STATIC mp_obj_t onewire_writebyte(mp_obj_t pin_in, mp_obj_t value_in) {
+    mp_hal_pin_obj_t pin = mp_hal_get_pin_obj(pin_in);
+    int value = mp_obj_get_int(value_in);
+    for (int i = 0; i < 8; ++i) {
+        onewire_bus_writebit(pin, value & 1);
+        value >>= 1;
+    }
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_2(onewire_writebyte_obj, onewire_writebyte);
+
+STATIC mp_obj_t onewire_crc8(mp_obj_t data) {
+    mp_buffer_info_t bufinfo;
+    mp_get_buffer_raise(data, &bufinfo, MP_BUFFER_READ);
+    uint8_t crc = 0;
+    for (size_t i = 0; i < bufinfo.len; ++i) {
+        uint8_t byte = ((uint8_t *)bufinfo.buf)[i];
+        for (int b = 0; b < 8; ++b) {
+            uint8_t fb_bit = (crc ^ byte) & 0x01;
+            if (fb_bit == 0x01) {
+                crc = crc ^ 0x18;
+            }
+            crc = (crc >> 1) & 0x7f;
+            if (fb_bit == 0x01) {
+                crc = crc | 0x80;
+            }
+            byte = byte >> 1;
+        }
+    }
+    return MP_OBJ_NEW_SMALL_INT(crc);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(onewire_crc8_obj, onewire_crc8);
+
+STATIC const mp_rom_map_elem_t onewire_module_globals_table[] = {
+    { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_onewire) },
+
+    { MP_ROM_QSTR(MP_QSTR_reset), MP_ROM_PTR(&onewire_reset_obj) },
+    { MP_ROM_QSTR(MP_QSTR_readbit), MP_ROM_PTR(&onewire_readbit_obj) },
+    { MP_ROM_QSTR(MP_QSTR_readbyte), MP_ROM_PTR(&onewire_readbyte_obj) },
+    { MP_ROM_QSTR(MP_QSTR_writebit), MP_ROM_PTR(&onewire_writebit_obj) },
+    { MP_ROM_QSTR(MP_QSTR_writebyte), MP_ROM_PTR(&onewire_writebyte_obj) },
+    { MP_ROM_QSTR(MP_QSTR_crc8), MP_ROM_PTR(&onewire_crc8_obj) },
+};
+
+STATIC MP_DEFINE_CONST_DICT(onewire_module_globals, onewire_module_globals_table);
+
+const mp_obj_module_t mp_module_onewire = {
+    .base = { &mp_type_module },
+    .globals = (mp_obj_dict_t *)&onewire_module_globals,
+};
+
+#endif // MICROPY_PY_ONEWIRE