circuitpython/ports/atmel-samd/common-hal/i2cslave/I2CSlave.c

253 lines
8.0 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2018 Noralf Trønnes
*
* 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 "shared-bindings/i2cslave/I2CSlave.h"
#include "common-hal/busio/I2C.h"
#include "lib/utils/interrupt_char.h"
#include "py/mperrno.h"
#include "py/mphal.h"
#include "py/runtime.h"
#include "hal/include/hal_gpio.h"
#include "peripherals/samd/sercom.h"
void common_hal_i2cslave_i2c_slave_construct(i2cslave_i2c_slave_obj_t *self,
const mcu_pin_obj_t *scl, const mcu_pin_obj_t *sda,
uint8_t *addresses, unsigned int num_addresses, bool smbus) {
uint8_t sercom_index;
uint32_t sda_pinmux, scl_pinmux;
Sercom *sercom = samd_i2c_get_sercom(scl, sda, &sercom_index, &sda_pinmux, &scl_pinmux);
if (sercom == NULL) {
mp_raise_ValueError(translate("Invalid pins"));
}
self->sercom = sercom;
gpio_set_pin_function(sda->number, GPIO_PIN_FUNCTION_OFF);
gpio_set_pin_function(scl->number, GPIO_PIN_FUNCTION_OFF);
gpio_set_pin_function(sda->number, sda_pinmux);
gpio_set_pin_function(scl->number, scl_pinmux);
self->sda_pin = sda->number;
self->scl_pin = scl->number;
claim_pin(sda);
claim_pin(scl);
samd_peripherals_sercom_clock_init(sercom, sercom_index);
sercom->I2CS.CTRLA.bit.SWRST = 1;
while (sercom->I2CS.CTRLA.bit.SWRST || sercom->I2CS.SYNCBUSY.bit.SWRST) {}
sercom->I2CS.CTRLB.bit.AACKEN = 0; // Automatic acknowledge is disabled.
if (num_addresses == 1) {
sercom->I2CS.CTRLB.bit.AMODE = 0x0; // MASK
sercom->I2CS.ADDR.bit.ADDR = addresses[0];
sercom->I2CS.ADDR.bit.ADDRMASK = 0x00; // Match exact address
} else if (num_addresses == 2) {
sercom->I2CS.CTRLB.bit.AMODE = 0x1; // 2_ADDRS
sercom->I2CS.ADDR.bit.ADDR = addresses[0];
sercom->I2CS.ADDR.bit.ADDRMASK = addresses[1];
} else {
uint32_t combined = 0; // all addresses OR'ed
uint32_t differ = 0; // bits that differ between addresses
for (unsigned int i = 0; i < num_addresses; i++) {
combined |= addresses[i];
differ |= addresses[0] ^ addresses[i];
}
sercom->I2CS.CTRLB.bit.AMODE = 0x0; // MASK
sercom->I2CS.ADDR.bit.ADDR = combined;
sercom->I2CS.ADDR.bit.ADDRMASK = differ;
}
self->addresses = addresses;
self->num_addresses = num_addresses;
if (smbus) {
sercom->I2CS.CTRLA.bit.LOWTOUTEN = 1; // Errata 12003
sercom->I2CS.CTRLA.bit.SEXTTOEN = 1; // Slave SCL Low Extend/Cumulative Time-Out 25ms
}
sercom->I2CS.CTRLA.bit.SCLSM = 0; // Clock stretch before ack
sercom->I2CS.CTRLA.bit.MODE = 0x04; // Slave mode
sercom->I2CS.CTRLA.bit.ENABLE = 1;
}
bool common_hal_i2cslave_i2c_slave_deinited(i2cslave_i2c_slave_obj_t *self) {
return self->sda_pin == NO_PIN;
}
void common_hal_i2cslave_i2c_slave_deinit(i2cslave_i2c_slave_obj_t *self) {
if (common_hal_i2cslave_i2c_slave_deinited(self)) {
return;
}
self->sercom->I2CS.CTRLA.bit.ENABLE = 0;
reset_pin_number(self->sda_pin);
reset_pin_number(self->scl_pin);
self->sda_pin = NO_PIN;
self->scl_pin = NO_PIN;
}
static int i2c_slave_check_error(i2cslave_i2c_slave_obj_t *self, bool raise) {
if (!self->sercom->I2CS.INTFLAG.bit.ERROR) {
return 0;
}
int err = MP_EIO;
if (self->sercom->I2CS.STATUS.bit.LOWTOUT || self->sercom->I2CS.STATUS.bit.SEXTTOUT) {
err = MP_ETIMEDOUT;
}
self->sercom->I2CS.INTFLAG.reg = SERCOM_I2CS_INTFLAG_ERROR; // Clear flag
if (raise) {
mp_raise_OSError(err);
}
return -err;
}
int common_hal_i2cslave_i2c_slave_is_addressed(i2cslave_i2c_slave_obj_t *self, uint8_t *address, bool *is_read, bool *is_restart)
{
int err = i2c_slave_check_error(self, false);
if (err) {
return err;
}
if (!self->sercom->I2CS.INTFLAG.bit.AMATCH) {
return 0;
}
self->writing = false;
*address = self->sercom->I2CS.DATA.reg >> 1;
*is_read = self->sercom->I2CS.STATUS.bit.DIR;
*is_restart = self->sercom->I2CS.STATUS.bit.SR;
for (unsigned int i = 0; i < self->num_addresses; i++) {
if (*address == self->addresses[i]) {
common_hal_i2cslave_i2c_slave_ack(self, true);
return 1;
}
}
// This should clear AMATCH, but it doesn't...
common_hal_i2cslave_i2c_slave_ack(self, false);
return 0;
}
int common_hal_i2cslave_i2c_slave_read_byte(i2cslave_i2c_slave_obj_t *self, uint8_t *data) {
for (int t = 0; t < 100 && !self->sercom->I2CS.INTFLAG.reg; t++) {
mp_hal_delay_us(10);
}
i2c_slave_check_error(self, true);
if (!self->sercom->I2CS.INTFLAG.bit.DRDY ||
self->sercom->I2CS.INTFLAG.bit.PREC ||
self->sercom->I2CS.INTFLAG.bit.AMATCH) {
return 0;
}
*data = self->sercom->I2CS.DATA.reg;
return 1;
}
int common_hal_i2cslave_i2c_slave_write_byte(i2cslave_i2c_slave_obj_t *self, uint8_t data) {
for (int t = 0; !self->sercom->I2CS.INTFLAG.reg && t < 100; t++) {
mp_hal_delay_us(10);
}
i2c_slave_check_error(self, true);
if (self->sercom->I2CS.INTFLAG.bit.PREC) {
return 0;
}
// RXNACK can carry over from the previous transfer
if (self->writing && self->sercom->I2CS.STATUS.bit.RXNACK) {
return 0;
}
self->writing = true;
if (!self->sercom->I2CS.INTFLAG.bit.DRDY) {
return 0;
}
self->sercom->I2CS.DATA.bit.DATA = data; // Send data
return 1;
}
void common_hal_i2cslave_i2c_slave_ack(i2cslave_i2c_slave_obj_t *self, bool ack) {
self->sercom->I2CS.CTRLB.bit.ACKACT = !ack;
self->sercom->I2CS.CTRLB.bit.CMD = 0x03;
}
void common_hal_i2cslave_i2c_slave_close(i2cslave_i2c_slave_obj_t *self) {
for (int t = 0; !self->sercom->I2CS.INTFLAG.reg && t < 100; t++) {
mp_hal_delay_us(10);
}
if (self->sercom->I2CS.INTFLAG.bit.AMATCH || !self->sercom->I2CS.STATUS.bit.CLKHOLD) {
return;
}
if (!self->sercom->I2CS.STATUS.bit.DIR) {
common_hal_i2cslave_i2c_slave_ack(self, false);
} else {
int i = 0;
while (self->sercom->I2CS.INTFLAG.reg == SERCOM_I2CS_INTFLAG_DRDY) {
if (mp_hal_is_interrupted()) {
return;
}
self->sercom->I2CS.DATA.bit.DATA = 0xff; // Send dummy byte
// Wait for a result (if any).
// test_byte_word.py::TestWord::test_write_seq leaves us with no INTFLAGs set in some of the tests
for (int t = 0; !self->sercom->I2CS.INTFLAG.reg && t < 100; t++) {
mp_hal_delay_us(10);
}
if (++i > 1000) { // Avoid getting stuck "forever"
mp_raise_OSError(MP_EIO);
}
}
}
if (self->sercom->I2CS.INTFLAG.bit.AMATCH) {
return;
}
if (self->sercom->I2CS.STATUS.bit.CLKHOLD) {
// Unable to release the clock.
// The slave might have to be re-initialized to get unstuck.
mp_raise_OSError(MP_EIO);
}
}