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micropython/ports/stm32/i2c.c

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C
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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2018 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/mperrno.h"
#include "py/mphal.h"
#include "py/runtime.h"
#include "i2c.h"
#if MICROPY_HW_ENABLE_HW_I2C
#if defined(STM32F4) || defined(STM32L1)
STATIC uint16_t i2c_timeout_ms[MICROPY_HW_MAX_I2C];
int i2c_init(i2c_t *i2c, mp_hal_pin_obj_t scl, mp_hal_pin_obj_t sda, uint32_t freq, uint16_t timeout_ms) {
uint32_t i2c_id = ((uint32_t)i2c - I2C1_BASE) / (I2C2_BASE - I2C1_BASE);
// Init pins
if (!mp_hal_pin_config_alt(scl, MP_HAL_PIN_MODE_ALT_OPEN_DRAIN, MP_HAL_PIN_PULL_UP, AF_FN_I2C, i2c_id + 1)) {
return -MP_EPERM;
}
if (!mp_hal_pin_config_alt(sda, MP_HAL_PIN_MODE_ALT_OPEN_DRAIN, MP_HAL_PIN_PULL_UP, AF_FN_I2C, i2c_id + 1)) {
return -MP_EPERM;
}
// Save timeout value
i2c_timeout_ms[i2c_id] = timeout_ms;
// Force reset I2C peripheral
RCC->APB1RSTR |= RCC_APB1RSTR_I2C1RST << i2c_id;
RCC->APB1RSTR &= ~(RCC_APB1RSTR_I2C1RST << i2c_id);
// Enable I2C peripheral clock
RCC->APB1ENR |= RCC_APB1ENR_I2C1EN << i2c_id;
volatile uint32_t tmp = RCC->APB1ENR; // delay after RCC clock enable
(void)tmp;
uint32_t PCLK1 = HAL_RCC_GetPCLK1Freq();
// Initialise I2C peripheral
i2c->CR1 = 0;
i2c->CR2 = PCLK1 / 1000000;
i2c->OAR1 = 0;
i2c->OAR2 = 0;
freq = MIN(freq, 400000);
// SM: MAX(4, PCLK1 / (F * 2))
// FM, 16:9 duty: 0xc000 | MAX(1, (PCLK1 / (F * (16 + 9))))
// (the PCLK1-1 and +1 at the end is to round the division up)
if (freq <= 100000) {
i2c->CCR = MAX(4, ((PCLK1 - 1) / (freq * 2) + 1));
} else {
i2c->CCR = 0xc000 | MAX(1, ((PCLK1 - 1) / (freq * 25) + 1));
}
// SM: 1000ns / (1/PCLK1) + 1 = PCLK1 * 1e-6 + 1
// FM: 300ns / (1/PCLK1) + 1 = 300e-3 * PCLK1 * 1e-6 + 1
if (freq <= 100000) {
i2c->TRISE = PCLK1 / 1000000 + 1; // 1000ns rise time in SM
} else {
i2c->TRISE = PCLK1 / 1000000 * 3 / 10 + 1; // 300ns rise time in FM
}
#if defined(I2C_FLTR_ANOFF)
i2c->FLTR = 0; // analog filter on, digital filter off
#endif
return 0;
}
STATIC int i2c_wait_sr1_set(i2c_t *i2c, uint32_t mask) {
uint32_t i2c_id = ((uint32_t)i2c - I2C1_BASE) / (I2C2_BASE - I2C1_BASE);
uint32_t t0 = HAL_GetTick();
while (!(i2c->SR1 & mask)) {
if (HAL_GetTick() - t0 >= i2c_timeout_ms[i2c_id]) {
i2c->CR1 &= ~I2C_CR1_PE;
return -MP_ETIMEDOUT;
}
}
return 0;
}
STATIC int i2c_wait_stop(i2c_t *i2c) {
uint32_t i2c_id = ((uint32_t)i2c - I2C1_BASE) / (I2C2_BASE - I2C1_BASE);
uint32_t t0 = HAL_GetTick();
while (i2c->CR1 & I2C_CR1_STOP) {
if (HAL_GetTick() - t0 >= i2c_timeout_ms[i2c_id]) {
i2c->CR1 &= ~I2C_CR1_PE;
return -MP_ETIMEDOUT;
}
}
i2c->CR1 &= ~I2C_CR1_PE;
return 0;
}
// For write: len = 0, 1 or N
// For read: len = 1, 2 or N; stop = true
int i2c_start_addr(i2c_t *i2c, int rd_wrn, uint16_t addr, size_t next_len, bool stop) {
if (!(i2c->CR1 & I2C_CR1_PE) && (i2c->SR2 & I2C_SR2_MSL)) {
// The F4 I2C peripheral can sometimes get into a bad state where it's disabled
// (PE low) but still an active master (MSL high). It seems the best way to get
// out of this is a full reset.
uint32_t i2c_id = ((uint32_t)i2c - I2C1_BASE) / (I2C2_BASE - I2C1_BASE);
RCC->APB1RSTR |= RCC_APB1RSTR_I2C1RST << i2c_id;
RCC->APB1RSTR &= ~(RCC_APB1RSTR_I2C1RST << i2c_id);
}
// It looks like it's possible to terminate the reading by sending a
// START condition instead of STOP condition but we don't support that.
if (rd_wrn) {
if (!stop) {
return -MP_EINVAL;
}
}
// Repurpose OAR1 to hold stop flag
i2c->OAR1 = stop;
// Enable peripheral and send START condition
i2c->CR1 |= I2C_CR1_PE;
i2c->CR1 |= I2C_CR1_START;
// Wait for START to be sent
int ret;
if ((ret = i2c_wait_sr1_set(i2c, I2C_SR1_SB))) {
return ret;
}
// Send the 7-bit address with read/write bit
i2c->DR = addr << 1 | rd_wrn;
// Wait for address to be sent
if ((ret = i2c_wait_sr1_set(i2c, I2C_SR1_AF | I2C_SR1_ADDR))) {
return ret;
}
// Check if the slave responded or not
if (i2c->SR1 & I2C_SR1_AF) {
// Got a NACK
i2c->CR1 |= I2C_CR1_STOP;
i2c_wait_stop(i2c); // Don't leak errors from this call
return -MP_ENODEV;
}
if (rd_wrn) {
// For reading, set up ACK/NACK control based on number of bytes to read (at least 1 byte)
if (next_len <= 1) {
// NACK next received byte
i2c->CR1 &= ~I2C_CR1_ACK;
} else if (next_len <= 2) {
// NACK second received byte
i2c->CR1 |= I2C_CR1_POS;
i2c->CR1 &= ~I2C_CR1_ACK;
} else {
// ACK next received byte
i2c->CR1 |= I2C_CR1_ACK;
}
}
// Read SR2 to clear SR1_ADDR
uint32_t sr2 = i2c->SR2;
(void)sr2;
return 0;
}
// next_len = 0 or N (>=2)
int i2c_read(i2c_t *i2c, uint8_t *dest, size_t len, size_t next_len) {
if (len == 0) {
return -MP_EINVAL;
}
if (next_len == 1) {
return -MP_EINVAL;
}
size_t remain = len + next_len;
if (remain == 1) {
// Special case
i2c->CR1 |= I2C_CR1_STOP;
int ret;
if ((ret = i2c_wait_sr1_set(i2c, I2C_SR1_RXNE))) {
return ret;
}
*dest = i2c->DR;
} else {
for (; len; --len) {
remain = len + next_len;
int ret;
if ((ret = i2c_wait_sr1_set(i2c, I2C_SR1_BTF))) {
return ret;
}
if (remain == 2) {
// In this case next_len == 0 (it's not allowed to be 1)
i2c->CR1 |= I2C_CR1_STOP;
*dest++ = i2c->DR;
*dest = i2c->DR;
break;
} else if (remain == 3) {
// NACK next received byte
i2c->CR1 &= ~I2C_CR1_ACK;
}
*dest++ = i2c->DR;
}
}
if (!next_len) {
// We sent a stop above, just wait for it to be finished
return i2c_wait_stop(i2c);
}
return 0;
}
// next_len = 0 or N
int i2c_write(i2c_t *i2c, const uint8_t *src, size_t len, size_t next_len) {
int ret;
if ((ret = i2c_wait_sr1_set(i2c, I2C_SR1_AF | I2C_SR1_TXE))) {
return ret;
}
// Write out the data
int num_acks = 0;
while (len--) {
i2c->DR = *src++;
if ((ret = i2c_wait_sr1_set(i2c, I2C_SR1_AF | I2C_SR1_BTF))) {
return ret;
}
if (i2c->SR1 & I2C_SR1_AF) {
// Slave did not respond to byte so stop sending
break;
}
++num_acks;
}
if (!next_len) {
if (i2c->OAR1) {
// Send a STOP and wait for it to finish
i2c->CR1 |= I2C_CR1_STOP;
if ((ret = i2c_wait_stop(i2c))) {
return ret;
}
}
}
return num_acks;
}
#elif defined(STM32F0) || defined(STM32F7) || defined(STM32H7) || defined(STM32L4)
#if defined(STM32H7)
#define APB1ENR APB1LENR
#define RCC_APB1ENR_I2C1EN RCC_APB1LENR_I2C1EN
#elif defined(STM32L4)
#define APB1ENR APB1ENR1
#define RCC_APB1ENR_I2C1EN RCC_APB1ENR1_I2C1EN
#if defined(STM32L432xx)
// Not a real peripheral, only needed for i2c_id calculation in i2c_init.
#define I2C2_BASE (APB1PERIPH_BASE + 0x5800UL)
#endif
#endif
STATIC uint16_t i2c_timeout_ms[MICROPY_HW_MAX_I2C];
static uint32_t i2c_get_id(i2c_t *i2c) {
#if defined(STM32H7)
if (i2c == I2C4) {
return 3;
}
#endif
return ((uint32_t)i2c - I2C1_BASE) / (I2C2_BASE - I2C1_BASE);
}
int i2c_init(i2c_t *i2c, mp_hal_pin_obj_t scl, mp_hal_pin_obj_t sda, uint32_t freq, uint16_t timeout_ms) {
uint32_t i2c_id = i2c_get_id(i2c);
// Init pins
if (!mp_hal_pin_config_alt(scl, MP_HAL_PIN_MODE_ALT_OPEN_DRAIN, MP_HAL_PIN_PULL_UP, AF_FN_I2C, i2c_id + 1)) {
return -MP_EPERM;
}
if (!mp_hal_pin_config_alt(sda, MP_HAL_PIN_MODE_ALT_OPEN_DRAIN, MP_HAL_PIN_PULL_UP, AF_FN_I2C, i2c_id + 1)) {
return -MP_EPERM;
}
// Save timeout value
i2c_timeout_ms[i2c_id] = timeout_ms;
// Enable I2C peripheral clock
volatile uint32_t tmp;
(void)tmp;
switch (i2c_id) {
case 0:
case 1:
case 2:
RCC->APB1ENR |= RCC_APB1ENR_I2C1EN << i2c_id;
tmp = RCC->APB1ENR; // delay after RCC clock enable
break;
#if defined(STM32H7)
case 3:
RCC->APB4ENR |= RCC_APB4ENR_I2C4EN;
tmp = RCC->APB4ENR; // delay after RCC clock enable
break;
#endif
}
// Initialise I2C peripheral
i2c->CR1 = 0;
i2c->CR2 = 0;
i2c->OAR1 = 0;
i2c->OAR2 = 0;
#if defined(STM32L4)
// These timing values are with f_I2CCLK=80MHz and are only approximate
if (freq >= 1000000) {
i2c->TIMINGR = 0x00300F33;
} else if (freq >= 400000) {
i2c->TIMINGR = 0x00702991;
} else if (freq >= 100000) {
i2c->TIMINGR = 0x10909CEC;
} else {
return -MP_EINVAL;
}
#else
// These timing values are for f_I2CCLK=54MHz and are only approximate
if (freq >= 1000000) {
i2c->TIMINGR = 0x50100103;
} else if (freq >= 400000) {
i2c->TIMINGR = 0x70330309;
} else if (freq >= 100000) {
i2c->TIMINGR = 0xb0420f13;
} else {
return -MP_EINVAL;
}
#endif
i2c->TIMEOUTR = 0;
return 0;
}
STATIC int i2c_wait_cr2_clear(i2c_t *i2c, uint32_t mask) {
uint32_t i2c_id = i2c_get_id(i2c);
uint32_t t0 = HAL_GetTick();
while (i2c->CR2 & mask) {
if (HAL_GetTick() - t0 >= i2c_timeout_ms[i2c_id]) {
i2c->CR1 &= ~I2C_CR1_PE;
return -MP_ETIMEDOUT;
}
}
return 0;
}
STATIC int i2c_wait_isr_set(i2c_t *i2c, uint32_t mask) {
uint32_t i2c_id = i2c_get_id(i2c);
uint32_t t0 = HAL_GetTick();
while (!(i2c->ISR & mask)) {
if (HAL_GetTick() - t0 >= i2c_timeout_ms[i2c_id]) {
i2c->CR1 &= ~I2C_CR1_PE;
return -MP_ETIMEDOUT;
}
}
return 0;
}
// len = 0, 1 or N
int i2c_start_addr(i2c_t *i2c, int rd_wrn, uint16_t addr, size_t len, bool stop) {
// Enable the peripheral and send the START condition with slave address
i2c->CR1 |= I2C_CR1_PE;
i2c->CR2 = (len > 1) << I2C_CR2_RELOAD_Pos
| (len > 0) << I2C_CR2_NBYTES_Pos
| rd_wrn << I2C_CR2_RD_WRN_Pos
| (addr & 0x7f) << 1;
i2c->CR2 |= I2C_CR2_START;
// Wait for address to be sent
int ret;
if ((ret = i2c_wait_cr2_clear(i2c, I2C_CR2_START))) {
return ret;
}
// Check if the slave responded or not
if (i2c->ISR & I2C_ISR_NACKF) {
// If we get a NACK then I2C periph unconditionally sends a STOP
i2c_wait_isr_set(i2c, I2C_ISR_STOPF); // Don't leak errors from this call
i2c->CR1 &= ~I2C_CR1_PE;
return -MP_ENODEV;
}
// Configure automatic STOP if needed
if (stop) {
i2c->CR2 |= I2C_CR2_AUTOEND;
}
// Repurpose OAR1 to indicate that we loaded CR2
i2c->OAR1 = 1;
return 0;
}
STATIC int i2c_check_stop(i2c_t *i2c) {
if (i2c->CR2 & I2C_CR2_AUTOEND) {
// Wait for the STOP condition and then disable the peripheral
int ret;
if ((ret = i2c_wait_isr_set(i2c, I2C_ISR_STOPF))) {
return ret;
}
i2c->CR1 &= ~I2C_CR1_PE;
}
return 0;
}
// next_len = 0 or N
int i2c_read(i2c_t *i2c, uint8_t *dest, size_t len, size_t next_len) {
if (i2c->OAR1) {
i2c->OAR1 = 0;
} else {
goto load_cr2;
}
// Read in the data
while (len--) {
int ret;
if ((ret = i2c_wait_isr_set(i2c, I2C_ISR_RXNE))) {
return ret;
}
*dest++ = i2c->RXDR;
load_cr2:
if (len) {
i2c->CR2 = (i2c->CR2 & I2C_CR2_AUTOEND)
| (len + next_len > 1) << I2C_CR2_RELOAD_Pos
| 1 << I2C_CR2_NBYTES_Pos;
}
}
if (!next_len) {
int ret;
if ((ret = i2c_check_stop(i2c))) {
return ret;
}
}
return 0;
}
// next_len = 0 or N
int i2c_write(i2c_t *i2c, const uint8_t *src, size_t len, size_t next_len) {
int num_acks = 0;
if (i2c->OAR1) {
i2c->OAR1 = 0;
} else {
goto load_cr2;
}
// Write out the data
while (len--) {
int ret;
if ((ret = i2c_wait_isr_set(i2c, I2C_ISR_TXE))) {
return ret;
}
i2c->TXDR = *src++;
if ((ret = i2c_wait_isr_set(i2c, I2C_ISR_TCR | I2C_ISR_TC | I2C_ISR_STOPF))) {
return ret;
}
uint32_t isr = i2c->ISR;
if (isr & I2C_ISR_NACKF) {
// Slave did not respond to byte so stop sending
if (!(isr & I2C_ISR_TXE)) {
// The TXDR is still full so the byte previous to that wasn't actually ACK'd
--num_acks;
}
break;
}
++num_acks;
load_cr2:
if (len) {
i2c->CR2 = (i2c->CR2 & I2C_CR2_AUTOEND)
| (len + next_len > 1) << I2C_CR2_RELOAD_Pos
| 1 << I2C_CR2_NBYTES_Pos;
}
}
if (!next_len) {
int ret;
if ((ret = i2c_check_stop(i2c))) {
return ret;
}
}
return num_acks;
}
#endif
#if defined(STM32F0) || defined(STM32F4) || defined(STM32F7) || defined(STM32H7)
int i2c_readfrom(i2c_t *i2c, uint16_t addr, uint8_t *dest, size_t len, bool stop) {
int ret;
if ((ret = i2c_start_addr(i2c, 1, addr, len, stop))) {
return ret;
}
return i2c_read(i2c, dest, len, 0);
}
int i2c_writeto(i2c_t *i2c, uint16_t addr, const uint8_t *src, size_t len, bool stop) {
int ret;
if ((ret = i2c_start_addr(i2c, 0, addr, len, stop))) {
return ret;
}
return i2c_write(i2c, src, len, 0);
}
#endif
STATIC const uint8_t i2c_available =
0
#if defined(MICROPY_HW_I2C1_SCL)
| 1 << 1
#endif
#if defined(MICROPY_HW_I2C2_SCL)
| 1 << 2
#endif
#if defined(MICROPY_HW_I2C3_SCL)
| 1 << 3
#endif
#if defined(MICROPY_HW_I2C4_SCL)
| 1 << 4
#endif
;
int i2c_find_peripheral(mp_obj_t id) {
int i2c_id = 0;
if (mp_obj_is_str(id)) {
const char *port = mp_obj_str_get_str(id);
if (0) {
#ifdef MICROPY_HW_I2C1_NAME
} else if (strcmp(port, MICROPY_HW_I2C1_NAME) == 0) {
i2c_id = 1;
#endif
#ifdef MICROPY_HW_I2C2_NAME
} else if (strcmp(port, MICROPY_HW_I2C2_NAME) == 0) {
i2c_id = 2;
#endif
#ifdef MICROPY_HW_I2C3_NAME
} else if (strcmp(port, MICROPY_HW_I2C3_NAME) == 0) {
i2c_id = 3;
#endif
#ifdef MICROPY_HW_I2C4_NAME
} else if (strcmp(port, MICROPY_HW_I2C4_NAME) == 0) {
i2c_id = 4;
#endif
} else {
mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("I2C(%s) doesn't exist"), port);
}
} else {
i2c_id = mp_obj_get_int(id);
if (i2c_id < 1 || i2c_id >= 8 * sizeof(i2c_available) || !(i2c_available & (1 << i2c_id))) {
mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("I2C(%d) doesn't exist"), i2c_id);
}
}
// check if the I2C is reserved for system use or not
if (MICROPY_HW_I2C_IS_RESERVED(i2c_id)) {
mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("I2C(%d) is reserved"), i2c_id);
}
return i2c_id;
}
#endif // MICROPY_HW_ENABLE_HW_I2C
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