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micropython/stm/accel.c

301 wiersze
8.8 KiB
C
Czysty Wina Historia

#include <stdio.h>
#include <stm32f4xx.h>
#include <stm32f4xx_rcc.h>
#include <stm32f4xx_gpio.h>
#include "misc.h"
#include "mpconfig.h"
#include "qstr.h"
#include "systick.h"
#include "obj.h"
#include "runtime.h"
#include "accel.h"
#define ACCEL_ADDR (0x4c)
void accel_init(void) {
RCC->APB1ENR |= RCC_APB1ENR_I2C1EN; // enable I2C1
//gpio_pin_init(GPIOB, 6 /* B6 is SCL */, 2 /* AF mode */, 1 /* open drain output */, 1 /* 25 MHz */, 0 /* no pull up or pull down */);
//gpio_pin_init(GPIOB, 7 /* B7 is SDA */, 2 /* AF mode */, 1 /* open drain output */, 1 /* 25 MHz */, 0 /* no pull up or pull down */);
//gpio_pin_af(GPIOB, 6, 4 /* AF 4 for I2C1 */);
//gpio_pin_af(GPIOB, 7, 4 /* AF 4 for I2C1 */);
// XXX untested GPIO init! (was above code)
GPIO_InitTypeDef GPIO_InitStructure;
// PB5 is connected to AVDD; pull high to enable MMA accel device
GPIOB->BSRRH = GPIO_Pin_5; // PB5 low to start with
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOB, &GPIO_InitStructure);
// 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);
// get clock speeds
RCC_ClocksTypeDef rcc_clocks;
RCC_GetClocksFreq(&rcc_clocks);
// disable the I2C peripheral before we configure it
I2C1->CR1 &= ~I2C_CR1_PE;
// program peripheral input clock
I2C1->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
I2C1->CCR = freq; // standard mode (speed), freq calculated as above
// configure rise time reg
I2C1->TRISE = (rcc_clocks.PCLK1_Frequency / 1000000) + 1; // formula for trise, gives maximum rise time
// enable the I2C peripheral
I2C1->CR1 |= I2C_CR1_PE;
// wait 20ms, then turn on AVDD, then wait 20ms again; this seems to work, but maybe can decrease delays
// doesn't work for soft reboot; 50ms doesn't work either...
sys_tick_delay_ms(20);
GPIOB->BSRRL = GPIO_Pin_5;
sys_tick_delay_ms(20);
// set START bit in CR1 to generate a start cond!
// init the chip via I2C commands
accel_start(ACCEL_ADDR, 1);
accel_send_byte(0);
accel_stop();
/*
// read and print all 11 registers
accel_start(ACCEL_ADDR, 1);
accel_send_byte(0);
accel_restart(ACCEL_ADDR, 0);
for (int i = 0; i <= 0xa; i++) {
int data;
if (i == 0xa) {
data = accel_read_nack();
} else {
data = accel_read_ack();
}
printf(" %02x", data);
}
printf("\n");
*/
// put into active mode
accel_start(ACCEL_ADDR, 1);
accel_send_byte(7); // mode
accel_send_byte(1); // active mode
accel_stop();
/*
// infinite loop to read values
for (;;) {
sys_tick_delay_ms(500);
accel_start(ACCEL_ADDR, 1);
accel_send_byte(0);
accel_restart(ACCEL_ADDR, 0);
for (int i = 0; i <= 3; i++) {
int data;
if (i == 3) {
data = accel_read_nack();
printf(" %02x\n", data);
} else {
data = accel_read_ack() & 0x3f;
if (data & 0x20) {
data |= ~0x1f;
}
printf(" % 2d", data);
}
}
}
*/
}
static uint32_t i2c_get_sr(void) {
// must read SR1 first, then SR2, as the read can clear some flags
uint32_t sr1 = I2C1->SR1;
uint32_t sr2 = I2C1->SR2;
return (sr2 << 16) | sr1;
}
void accel_restart(uint8_t addr, int write) {
// send start condition
I2C1->CR1 |= I2C_CR1_START;
// wait for BUSY, MSL and SB --> Slave has acknowledged start condition
uint32_t timeout = 1000000;
while ((i2c_get_sr() & 0x00030001) != 0x00030001) {
if (--timeout == 0) {
printf("timeout in accel_restart\n");
return;
}
}
if (write) {
// send address and write bit
I2C1->DR = (addr << 1) | 0;
// wait for BUSY, MSL, ADDR, TXE and TRA
timeout = 1000000;
while ((i2c_get_sr() & 0x00070082) != 0x00070082) {
if (--timeout == 0) {
printf("timeout in accel_restart write\n");
return;
}
}
} else {
// send address and read bit
I2C1->DR = (addr << 1) | 1;
// wait for BUSY, MSL and ADDR flags
timeout = 1000000;
while ((i2c_get_sr() & 0x00030002) != 0x00030002) {
if (--timeout == 0) {
printf("timeout in accel_restart read\n");
return;
}
}
}
}
void accel_start(uint8_t addr, int write) {
// wait until I2C is not busy
uint32_t timeout = 1000000;
while (I2C1->SR2 & I2C_SR2_BUSY) {
if (--timeout == 0) {
printf("timeout in accel_start\n");
return;
}
}
// do rest of start
accel_restart(addr, write);
}
void accel_send_byte(uint8_t data) {
// send byte
I2C1->DR = data;
// wait for TRA, BUSY, MSL, TXE and BTF (byte transmitted)
uint32_t timeout = 1000000;
while ((i2c_get_sr() & 0x00070084) != 0x00070084) {
if (--timeout == 0) {
printf("timeout in accel_send_byte\n");
return;
}
}
}
uint8_t accel_read_ack(void) {
// enable ACK of received byte
I2C1->CR1 |= I2C_CR1_ACK;
// wait for BUSY, MSL and RXNE (byte received)
uint32_t timeout = 1000000;
while ((i2c_get_sr() & 0x00030040) != 0x00030040) {
if (--timeout == 0) {
printf("timeout in accel_read_ack\n");
break;
}
}
// read and return data
uint8_t data = I2C1->DR;
return data;
}
uint8_t accel_read_nack(void) {
// disable ACK of received byte (to indicate end of receiving)
I2C1->CR1 &= (uint16_t)~((uint16_t)I2C_CR1_ACK);
// last byte should apparently also generate a stop condition
I2C1->CR1 |= I2C_CR1_STOP;
// wait for BUSY, MSL and RXNE (byte received)
uint32_t timeout = 1000000;
while ((i2c_get_sr() & 0x00030040) != 0x00030040) {
if (--timeout == 0) {
printf("timeout in accel_read_nack\n");
break;
}
}
// read and return data
uint8_t data = I2C1->DR;
return data;
}
void accel_stop(void) {
// send stop condition
I2C1->CR1 |= I2C_CR1_STOP;
}
/******************************************************************************/
/* Micro Python bindings */
int accel_buf[12];
mp_obj_t pyb_accel_read(void) {
for (int i = 0; i <= 6; i += 3) {
accel_buf[0 + i] = accel_buf[0 + i + 3];
accel_buf[1 + i] = accel_buf[1 + i + 3];
accel_buf[2 + i] = accel_buf[2 + i + 3];
}
accel_start(ACCEL_ADDR, 1);
accel_send_byte(0);
accel_restart(ACCEL_ADDR, 0);
for (int i = 0; i <= 2; i++) {
int v = accel_read_ack() & 0x3f;
if (v & 0x20) {
v |= ~0x1f;
}
accel_buf[9 + i] = v;
}
int jolt_info = accel_read_nack();
mp_obj_t data[4];
data[0] = mp_obj_new_int(accel_buf[0] + accel_buf[3] + accel_buf[6] + accel_buf[9]);
data[1] = mp_obj_new_int(accel_buf[1] + accel_buf[4] + accel_buf[7] + accel_buf[10]);
data[2] = mp_obj_new_int(accel_buf[2] + accel_buf[5] + accel_buf[8] + accel_buf[11]);
data[3] = mp_obj_new_int(jolt_info);
return mp_obj_new_tuple(4, data);
}
MP_DEFINE_CONST_FUN_OBJ_0(pyb_accel_read_obj, pyb_accel_read);
mp_obj_t pyb_accel_read_all(void) {
mp_obj_t data[11];
accel_start(ACCEL_ADDR, 1);
accel_send_byte(0);
accel_restart(ACCEL_ADDR, 0);
for (int i = 0; i <= 9; i++) {
data[i] = mp_obj_new_int(accel_read_ack());
}
data[10] = mp_obj_new_int(accel_read_nack());
return mp_obj_new_tuple(11, data);
}
MP_DEFINE_CONST_FUN_OBJ_0(pyb_accel_read_all_obj, pyb_accel_read_all);
mp_obj_t pyb_accel_write_mode(mp_obj_t o_int, mp_obj_t o_mode) {
accel_start(ACCEL_ADDR, 1);
accel_send_byte(6); // start at int
accel_send_byte(mp_obj_get_int(o_int));
accel_send_byte(mp_obj_get_int(o_mode));
accel_stop();
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_2(pyb_accel_write_mode_obj, pyb_accel_write_mode);
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