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esp32: Add support for hardware I2C.

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This commit is contained in:
Damien George 2019-07-10 13:43:52 +10:00
parent 3967dd68e8
commit a29334761d
4 changed files with 192 additions and 3 deletions
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14
docs/esp32/quickref.rst
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@ -303,14 +303,22 @@ Hardware SPI has the same methods as Software SPI above::
I2C bus
-------
The I2C driver is implemented in software and works on all pins,
and is accessed via the :ref:`machine.I2C <machine.I2C>` class::
The I2C driver has both software and hardware implementations, and the two
hardware peripherals have identifiers 0 and 1. Any available output-capable
pins can be used for SCL and SDA. The driver is accessed via the
:ref:`machine.I2C <machine.I2C>` class::
from machine import Pin, I2C
# construct an I2C bus
# construct a software I2C bus
i2c = I2C(scl=Pin(5), sda=Pin(4), freq=100000)
# construct a hardware I2C bus
i2c = I2C(0)
i2c = I2C(1, scl=Pin(5), sda=Pin(4), freq=400000)
i2c.scan() # scan for slave devices
i2c.readfrom(0x3a, 4) # read 4 bytes from slave device with address 0x3a
i2c.writeto(0x3a, '12') # write '12' to slave device with address 0x3a

1
ports/esp32/Makefile
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@ -181,6 +181,7 @@ SRC_C = \
machine_touchpad.c \
machine_adc.c \
machine_dac.c \
machine_i2c.c \
machine_pwm.c \
machine_uart.c \
modmachine.c \

179
ports/esp32/machine_i2c.c Normal file
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@ -0,0 +1,179 @@
/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2019 Damien P. George
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "py/runtime.h"
#include "py/mphal.h"
#include "py/mperrno.h"
#include "extmod/machine_i2c.h"
#include "driver/i2c.h"
#define I2C_0_DEFAULT_SCL (GPIO_NUM_18)
#define I2C_0_DEFAULT_SDA (GPIO_NUM_19)
#define I2C_1_DEFAULT_SCL (GPIO_NUM_25)
#define I2C_1_DEFAULT_SDA (GPIO_NUM_26)
#define I2C_DEFAULT_TIMEOUT_US (10000) // 10ms
typedef struct _machine_hw_i2c_obj_t {
mp_obj_base_t base;
i2c_port_t port : 8;
gpio_num_t scl : 8;
gpio_num_t sda : 8;
} machine_hw_i2c_obj_t;
STATIC const mp_obj_type_t machine_hw_i2c_type;
STATIC machine_hw_i2c_obj_t machine_hw_i2c_obj[I2C_NUM_MAX];
STATIC void machine_hw_i2c_init(machine_hw_i2c_obj_t *self, uint32_t freq, uint32_t timeout_us, bool first_init) {
if (!first_init) {
i2c_driver_delete(self->port);
}
i2c_config_t conf = {
.mode = I2C_MODE_MASTER,
.sda_io_num = self->sda,
.sda_pullup_en = GPIO_PULLUP_ENABLE,
.scl_io_num = self->scl,
.scl_pullup_en = GPIO_PULLUP_ENABLE,
.master.clk_speed = freq,
};
i2c_param_config(self->port, &conf);
i2c_set_timeout(self->port, I2C_APB_CLK_FREQ / 1000000 * timeout_us);
i2c_driver_install(self->port, I2C_MODE_MASTER, 0, 0, 0);
}
int machine_hw_i2c_transfer(mp_obj_base_t *self_in, uint16_t addr, size_t n, mp_machine_i2c_buf_t *bufs, unsigned int flags) {
machine_hw_i2c_obj_t *self = MP_OBJ_TO_PTR(self_in);
i2c_cmd_handle_t cmd = i2c_cmd_link_create();
i2c_master_start(cmd);
i2c_master_write_byte(cmd, addr << 1 | (flags & MP_MACHINE_I2C_FLAG_READ), true);
int data_len = 0;
for (; n--; ++bufs) {
if (flags & MP_MACHINE_I2C_FLAG_READ) {
i2c_master_read(cmd, bufs->buf, bufs->len, n == 0 ? I2C_MASTER_LAST_NACK : I2C_MASTER_ACK);
} else {
if (bufs->len != 0) {
i2c_master_write(cmd, bufs->buf, bufs->len, true);
}
}
data_len += bufs->len;
}
if (flags & MP_MACHINE_I2C_FLAG_STOP) {
i2c_master_stop(cmd);
}
// TODO proper timeout
esp_err_t err = i2c_master_cmd_begin(self->port, cmd, 100 * (1 + data_len) / portTICK_RATE_MS);
i2c_cmd_link_delete(cmd);
if (err == ESP_FAIL) {
return -MP_ENODEV;
} else if (err == ESP_ERR_TIMEOUT) {
return -MP_ETIMEDOUT;
} else if (err != ESP_OK) {
return -abs(err);
}
return data_len;
}
/******************************************************************************/
// MicroPython bindings for machine API
STATIC void machine_hw_i2c_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
machine_hw_i2c_obj_t *self = MP_OBJ_TO_PTR(self_in);
int h, l;
i2c_get_period(self->port, &h, &l);
mp_printf(print, "I2C(%u, scl=%u, sda=%u, freq=%u)",
self->port, self->scl, self->sda, I2C_APB_CLK_FREQ / (h + l));
}
mp_obj_t machine_hw_i2c_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
// Parse args
enum { ARG_id, ARG_scl, ARG_sda, ARG_freq, ARG_timeout };
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_id, MP_ARG_REQUIRED | MP_ARG_OBJ },
{ MP_QSTR_scl, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
{ MP_QSTR_sda, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
{ MP_QSTR_freq, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 400000} },
{ MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = I2C_DEFAULT_TIMEOUT_US} },
};
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all_kw_array(n_args, n_kw, all_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
// Get I2C bus
mp_int_t i2c_id = mp_obj_get_int(args[ARG_id].u_obj);
if (!(I2C_NUM_0 <= i2c_id && i2c_id < I2C_NUM_MAX)) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "I2C(%d) doesn't exist", i2c_id));
}
// Get static peripheral object
machine_hw_i2c_obj_t *self = (machine_hw_i2c_obj_t*)&machine_hw_i2c_obj[i2c_id];
bool first_init = false;
if (self->base.type == NULL) {
// Created for the first time, set default pins
self->base.type = &machine_hw_i2c_type;
self->port = i2c_id;
if (self->port == I2C_NUM_0) {
self->scl = I2C_0_DEFAULT_SCL;
self->sda = I2C_0_DEFAULT_SDA;
} else {
self->scl = I2C_1_DEFAULT_SCL;
self->sda = I2C_1_DEFAULT_SDA;
}
first_init = true;
}
// Set SCL/SDA pins if given
if (args[ARG_scl].u_obj != MP_OBJ_NULL) {
self->scl = mp_hal_get_pin_obj(args[ARG_scl].u_obj);
}
if (args[ARG_sda].u_obj != MP_OBJ_NULL) {
self->sda = mp_hal_get_pin_obj(args[ARG_sda].u_obj);
}
// Initialise the I2C peripheral
machine_hw_i2c_init(self, args[ARG_freq].u_int, args[ARG_timeout].u_int, first_init);
return MP_OBJ_FROM_PTR(self);
}
STATIC const mp_machine_i2c_p_t machine_hw_i2c_p = {
.transfer = machine_hw_i2c_transfer,
};
STATIC const mp_obj_type_t machine_hw_i2c_type = {
{ &mp_type_type },
.name = MP_QSTR_I2C,
.print = machine_hw_i2c_print,
.make_new = machine_hw_i2c_make_new,
.protocol = &machine_hw_i2c_p,
.locals_dict = (mp_obj_dict_t*)&mp_machine_soft_i2c_locals_dict,
};

1
ports/esp32/mpconfigport.h
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@ -137,6 +137,7 @@
#define MICROPY_PY_MACHINE_PIN_MAKE_NEW mp_pin_make_new
#define MICROPY_PY_MACHINE_PULSE (1)
#define MICROPY_PY_MACHINE_I2C (1)
#define MICROPY_PY_MACHINE_I2C_MAKE_NEW machine_hw_i2c_make_new
#define MICROPY_PY_MACHINE_SPI (1)
#define MICROPY_PY_MACHINE_SPI_MSB (0)
#define MICROPY_PY_MACHINE_SPI_LSB (1)