365 lines
11 KiB
C
365 lines
11 KiB
C
#include <stdio.h>
|
|
|
|
#include <stm32f4xx.h>
|
|
#include <stm32f4xx_rcc.h>
|
|
#include <stm32f4xx_gpio.h>
|
|
|
|
#include "misc.h"
|
|
#include "systick.h"
|
|
#include "mpconfig.h"
|
|
#include "obj.h"
|
|
|
|
typedef enum {
|
|
PYB_I2C_1 = 0,
|
|
PYB_I2C_2 = 1,
|
|
} pyb_i2c_t;
|
|
|
|
typedef enum {
|
|
I2C_STATE_IDLE = 0,
|
|
I2C_STATE_WRITE = 1,
|
|
I2C_STATE_READ = 2,
|
|
} i2c_state_t;
|
|
|
|
// set to true if the port has already been initialized
|
|
bool i2c1_port_initialized = false;
|
|
bool i2c2_port_initialized = false;
|
|
|
|
static I2C_TypeDef * _i2c_port_addr(pyb_i2c_t i2c_port) {
|
|
if (i2c_port == PYB_I2C_1) {
|
|
return I2C1;
|
|
}
|
|
if (i2c_port == PYB_I2C_2) {
|
|
return I2C2;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
// todo - perhaps there should be some global resource management for gpio
|
|
// this function would fail if the i2c pins have already been defined for
|
|
// use by another python object
|
|
// as it is, this always returns true (unless i2c_port is invalid)
|
|
static bool _i2c_init(pyb_i2c_t i2c_port) {
|
|
GPIO_InitTypeDef GPIO_InitStructure;
|
|
|
|
I2C_TypeDef *i2c = _i2c_port_addr(i2c_port);
|
|
if (i2c == NULL)
|
|
return false;
|
|
|
|
if (i2c_port == PYB_I2C_1) {
|
|
if (i2c1_port_initialized == true) {
|
|
return true;
|
|
}
|
|
RCC->APB1ENR |= RCC_APB1ENR_I2C1EN; // enable I2C1
|
|
|
|
// PB6=SCL, PB7=SDA
|
|
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
|
|
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
|
|
GPIO_InitStructure.GPIO_OType = GPIO_OType_OD;
|
|
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_25MHz;
|
|
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
|
|
GPIO_Init(GPIOB, &GPIO_InitStructure);
|
|
|
|
// alternate functions for SCL and SDA
|
|
GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_I2C1);
|
|
GPIO_PinAFConfig(GPIOB, GPIO_PinSource7, GPIO_AF_I2C1);
|
|
|
|
|
|
i2c1_port_initialized = true;
|
|
}
|
|
|
|
if (i2c_port == PYB_I2C_2) {
|
|
if (i2c2_port_initialized == true) {
|
|
return true;
|
|
}
|
|
RCC->APB1ENR |= RCC_APB1ENR_I2C2EN; // enable I2C2
|
|
|
|
// PB10=SCL, PB11=SDA
|
|
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10 | GPIO_Pin_11;
|
|
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
|
|
GPIO_InitStructure.GPIO_OType = GPIO_OType_OD;
|
|
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_25MHz;
|
|
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
|
|
GPIO_Init(GPIOB, &GPIO_InitStructure);
|
|
|
|
// alternate functions for SCL and SDA
|
|
GPIO_PinAFConfig(GPIOB, GPIO_PinSource10, GPIO_AF_I2C2);
|
|
GPIO_PinAFConfig(GPIOB, GPIO_PinSource11, GPIO_AF_I2C2);
|
|
|
|
i2c2_port_initialized = true;
|
|
}
|
|
|
|
// get clock speeds
|
|
RCC_ClocksTypeDef rcc_clocks;
|
|
RCC_GetClocksFreq(&rcc_clocks);
|
|
|
|
// disable the I2C peripheral before we configure it
|
|
i2c->CR1 &= ~I2C_CR1_PE;
|
|
|
|
// program peripheral input clock
|
|
i2c->CR2 = 4; // no interrupts; 4 MHz (hopefully!) (could go up to 42MHz)
|
|
|
|
// configure clock control reg
|
|
uint32_t freq = rcc_clocks.PCLK1_Frequency / (100000 << 1); // want 100kHz, this is the formula for freq
|
|
i2c->CCR = freq; // standard mode (speed), freq calculated as above
|
|
|
|
// configure rise time reg
|
|
i2c->TRISE = (rcc_clocks.PCLK1_Frequency / 1000000) + 1; // formula for trise, gives maximum rise time
|
|
|
|
// enable the I2C peripheral
|
|
i2c->CR1 |= I2C_CR1_PE;
|
|
|
|
return true;
|
|
}
|
|
|
|
static uint32_t _i2c_get_sr(pyb_i2c_t i2c_port) {
|
|
// must read SR1 first, then SR2, as the read can clear some flags
|
|
I2C_TypeDef *i2c = _i2c_port_addr(i2c_port);
|
|
if (i2c == NULL) return 0;
|
|
|
|
uint32_t sr1 = i2c->SR1;
|
|
uint32_t sr2 = i2c->SR2;
|
|
return (sr2 << 16) | sr1;
|
|
}
|
|
|
|
static bool _i2c_restart(pyb_i2c_t i2c_port, uint8_t addr, int write) {
|
|
I2C_TypeDef *i2c = _i2c_port_addr(i2c_port);
|
|
if (i2c == NULL) return false;
|
|
|
|
// send start condition
|
|
i2c->CR1 |= I2C_CR1_START;
|
|
|
|
// wait for BUSY, MSL and SB --> Slave has acknowledged start condition
|
|
uint32_t timeout = 1000000;
|
|
while ((_i2c_get_sr(i2c_port) & 0x00030001) != 0x00030001) {
|
|
if (--timeout == 0) {
|
|
//printf("timeout in _i2c_restart\n");
|
|
return false;
|
|
}
|
|
}
|
|
|
|
if (write) {
|
|
// send address and write bit
|
|
i2c->DR = (addr << 1) | 0;
|
|
// wait for BUSY, MSL, ADDR, TXE and TRA
|
|
timeout = 1000000;
|
|
while ((_i2c_get_sr(i2c_port) & 0x00070082) != 0x00070082) {
|
|
if (--timeout == 0) {
|
|
//printf("timeout in _i2c_restart write\n");
|
|
return false;
|
|
}
|
|
}
|
|
} else {
|
|
// send address and read bit
|
|
i2c->DR = (addr << 1) | 1;
|
|
// wait for BUSY, MSL and ADDR flags
|
|
timeout = 1000000;
|
|
while ((_i2c_get_sr(i2c_port) & 0x00030002) != 0x00030002) {
|
|
if (--timeout == 0) {
|
|
//printf("timeout in _i2c_restart read\n");
|
|
return false;
|
|
}
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
static bool _i2c_send_byte(pyb_i2c_t i2c_port, uint8_t data) {
|
|
I2C_TypeDef *i2c = _i2c_port_addr(i2c_port);
|
|
if (i2c == NULL) return false;
|
|
|
|
// send byte
|
|
i2c->DR = data;
|
|
// wait for TRA, BUSY, MSL, TXE and BTF (byte transmitted)
|
|
uint32_t timeout = 1000000;
|
|
while ((_i2c_get_sr(i2c_port) & 0x00070084) != 0x00070084) {
|
|
if (--timeout == 0) {
|
|
//printf("timeout in _i2c_send_byte\n");
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
static uint8_t _i2c_read_ack(pyb_i2c_t i2c_port) {
|
|
I2C_TypeDef *i2c = _i2c_port_addr(i2c_port);
|
|
if (i2c == NULL) return 0;
|
|
|
|
// enable ACK of received byte
|
|
i2c->CR1 |= I2C_CR1_ACK;
|
|
// wait for BUSY, MSL and RXNE (byte received)
|
|
uint32_t timeout = 1000000;
|
|
while ((_i2c_get_sr(i2c_port) & 0x00030040) != 0x00030040) {
|
|
if (--timeout == 0) {
|
|
//printf("timeout in _i2c_read_ack\n");
|
|
break;
|
|
}
|
|
}
|
|
// read and return data
|
|
uint8_t data = i2c->DR;
|
|
return data;
|
|
}
|
|
|
|
static uint8_t _i2c_read_nack(pyb_i2c_t i2c_port) {
|
|
I2C_TypeDef *i2c = _i2c_port_addr(i2c_port);
|
|
if (i2c == NULL) return 0;
|
|
|
|
// disable ACK of received byte (to indicate end of receiving)
|
|
i2c->CR1 &= (uint16_t)~((uint16_t)I2C_CR1_ACK);
|
|
// last byte should apparently also generate a stop condition
|
|
i2c->CR1 |= I2C_CR1_STOP;
|
|
// wait for BUSY, MSL and RXNE (byte received)
|
|
uint32_t timeout = 1000000;
|
|
while ((_i2c_get_sr(i2c_port) & 0x00030040) != 0x00030040) {
|
|
if (--timeout == 0) {
|
|
//printf("timeout in _i2c_read_nack\n");
|
|
break;
|
|
}
|
|
}
|
|
// read and return data
|
|
uint8_t data = i2c->DR;
|
|
return data;
|
|
}
|
|
|
|
static bool _i2c_start(pyb_i2c_t i2c_port) {
|
|
I2C_TypeDef *i2c = _i2c_port_addr(i2c_port);
|
|
if (i2c == NULL) return false;
|
|
|
|
// wait until I2C is not busy
|
|
uint32_t timeout = 1000000;
|
|
while (i2c->SR2 & I2C_SR2_BUSY) {
|
|
if (--timeout == 0) {
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
static void _i2c_stop(pyb_i2c_t i2c_port) {
|
|
I2C_TypeDef *i2c = _i2c_port_addr(i2c_port);
|
|
if (i2c == NULL) return;
|
|
|
|
// send stop condition
|
|
i2c->CR1 |= I2C_CR1_STOP;
|
|
}
|
|
|
|
/******************************************************************************/
|
|
/* Micro Python bindings */
|
|
|
|
typedef struct _pyb_i2c_obj_t {
|
|
mp_obj_base_t base;
|
|
pyb_i2c_t i2c_port;
|
|
int i2c_addr;
|
|
i2c_state_t i2c_state;
|
|
} pyb_i2c_obj_t;
|
|
|
|
void i2c_obj_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in) {
|
|
pyb_i2c_obj_t *self = self_in;
|
|
print(env, "<I2C%lu addr:%lu>", (unsigned int)self->i2c_port, (unsigned int)self->i2c_addr);
|
|
}
|
|
|
|
// calls _i2c_start with write=0,1 depending on LSB of i2c_addr
|
|
mp_obj_t i2c_obj_start(mp_obj_t self_in) {
|
|
pyb_i2c_obj_t *self = self_in;
|
|
if (self->i2c_state != I2C_STATE_IDLE) {
|
|
_i2c_stop(self->i2c_port);
|
|
self->i2c_state = I2C_STATE_IDLE;
|
|
}
|
|
if (_i2c_start(self->i2c_port) == true)
|
|
return mp_const_true;
|
|
return mp_const_false;
|
|
}
|
|
|
|
mp_obj_t i2c_obj_write(mp_obj_t self_in, mp_obj_t data_in) {
|
|
pyb_i2c_obj_t *self = self_in;
|
|
if (self->i2c_state != I2C_STATE_WRITE) {
|
|
if (_i2c_restart(self->i2c_port, self->i2c_addr, 1) == false) {
|
|
_i2c_stop(self->i2c_port);
|
|
self->i2c_state = I2C_STATE_IDLE;
|
|
return mp_const_false;
|
|
}
|
|
self->i2c_state = I2C_STATE_WRITE;
|
|
}
|
|
uint8_t data = mp_obj_get_int(data_in);
|
|
if (_i2c_send_byte(self->i2c_port, data) == false)
|
|
return mp_const_false;
|
|
return mp_const_true;
|
|
}
|
|
|
|
mp_obj_t i2c_obj_read(mp_obj_t self_in) {
|
|
pyb_i2c_obj_t *self = self_in;
|
|
if (self->i2c_state != I2C_STATE_READ) {
|
|
if (_i2c_restart(self->i2c_port, self->i2c_addr, 0) == false) {
|
|
_i2c_stop(self->i2c_port);
|
|
self->i2c_state = I2C_STATE_IDLE;
|
|
return mp_const_false;
|
|
}
|
|
self->i2c_state = I2C_STATE_READ;
|
|
}
|
|
uint8_t data = _i2c_read_ack(self->i2c_port);
|
|
return mp_obj_new_int(data);
|
|
}
|
|
|
|
mp_obj_t i2c_obj_readAndStop(mp_obj_t self_in) {
|
|
pyb_i2c_obj_t *self = self_in;
|
|
if (self->i2c_state != I2C_STATE_READ) {
|
|
if (_i2c_restart(self->i2c_port, self->i2c_addr, 0) == false) {
|
|
_i2c_stop(self->i2c_port);
|
|
self->i2c_state = I2C_STATE_IDLE;
|
|
return mp_const_false;
|
|
}
|
|
}
|
|
uint8_t data = _i2c_read_nack(self->i2c_port);
|
|
self->i2c_state = I2C_STATE_IDLE;
|
|
return mp_obj_new_int(data);
|
|
}
|
|
|
|
mp_obj_t i2c_obj_stop(mp_obj_t self_in) {
|
|
pyb_i2c_obj_t *self = self_in;
|
|
_i2c_stop(self->i2c_port);
|
|
self->i2c_state = I2C_STATE_IDLE;
|
|
return mp_const_none;
|
|
}
|
|
|
|
static MP_DEFINE_CONST_FUN_OBJ_1(i2c_obj_start_obj, i2c_obj_start);
|
|
static MP_DEFINE_CONST_FUN_OBJ_2(i2c_obj_write_obj, i2c_obj_write);
|
|
static MP_DEFINE_CONST_FUN_OBJ_1(i2c_obj_read_obj, i2c_obj_read);
|
|
static MP_DEFINE_CONST_FUN_OBJ_1(i2c_obj_readAndStop_obj, i2c_obj_readAndStop);
|
|
static MP_DEFINE_CONST_FUN_OBJ_1(i2c_obj_stop_obj, i2c_obj_stop);
|
|
|
|
static const mp_method_t i2c_methods[] = {
|
|
{ "start", &i2c_obj_start_obj },
|
|
{ "write", &i2c_obj_write_obj },
|
|
{ "read", &i2c_obj_read_obj },
|
|
{ "readAndStop", &i2c_obj_readAndStop_obj },
|
|
{ "stop", &i2c_obj_stop_obj },
|
|
{ NULL, NULL },
|
|
};
|
|
|
|
static const mp_obj_type_t i2c_obj_type = {
|
|
{ &mp_const_type },
|
|
"I2C",
|
|
.print = i2c_obj_print,
|
|
.methods = i2c_methods,
|
|
};
|
|
|
|
// create the I2C object
|
|
// currently support either I2C1 (i2c_id = 0) or I2C2 (i2c_id = 1)
|
|
|
|
mp_obj_t pyb_I2C(mp_obj_t i2c_id, mp_obj_t i2c_addr) {
|
|
pyb_i2c_t i2c_port;
|
|
switch(mp_obj_get_int(i2c_id)) {
|
|
case 0: i2c_port = PYB_I2C_1; break;
|
|
case 1: i2c_port = PYB_I2C_2; break;
|
|
default: return mp_const_none;
|
|
}
|
|
if (_i2c_init(i2c_port) == false) {
|
|
return mp_const_none;
|
|
}
|
|
pyb_i2c_obj_t *o = m_new_obj(pyb_i2c_obj_t);
|
|
o->base.type = &i2c_obj_type;
|
|
o->i2c_port = i2c_port;
|
|
o->i2c_addr = mp_obj_get_int(i2c_addr);
|
|
o->i2c_state = I2C_STATE_IDLE;
|
|
return o;
|
|
}
|