Hi all,
I'm trying to connect to the UBLOX M8Q MAX using the I2C on my SAMD21.
The address of this module is 0x42 and there are only a minimum needed. 0xFD, 0xFE and 0xFF from what i got out of the U-blox datasheet.
Currently I'm unable to setup the proper I2C master connecting.
After the setup of the master I have tried several write or read functions.
There are 3 of them included in the code
<
#include "sam.h"
#include "tmr.h"
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#define I2C_SERCOM_PORT_PMUX PORT_PMUX_PMUXE_C_Val
#define I2C_SERCOM_PINS_PORT_GROUP 0
#define I2C_SERCOM_SDA_PIN PORT_PA16
#define I2C_SERCOM_SCL_PIN PORT_PA17
#define I2C_SERCOM SERCOM1
#define I2C_SERCOM_APBxMASK PM_APBCMASK_SERCOM1
#define I2C_SERCOM_GCLK_ID_CORE SERCOM1_GCLK_ID_CORE
#define I2C_SERCOM_CLK_GEN 0
#define I2C_SERCOM_IRQ_HANDLER SERCOM1_Handler
#define I2C_SERCOM_IRQn SERCOM1_IRQn
#define Baudrate 57600
#define Clockfreq 8000000
#define FAST_MODE 0x0
#define GPS_ADR 0x42
#define BUF_SIZE 3
uint8_t gpsreg = 0xFD;
uint8_t tx_buf[BUF_SIZE] = {1, 2, 3};
uint8_t rx_buf[BUF_SIZE];
uint8_t i;
volatile bool tx_done = false, rx_done = false;
enum
{
I2C_TRANSFER_WRITE = 0,
I2C_TRANSFER_READ = 1,
};
void SERCOM1_Handler(void)
{
if(I2C_SERCOM->I2CM.INTFLAG.bit.MB)
{
if(i == BUF_SIZE)
{
I2C_SERCOM->I2CM.CTRLB.bit.CMD = 0x3;
while(I2C_SERCOM->I2CM.SYNCBUSY.bit.SYSOP);
tx_done = true;
i=0;
}
else
{
I2C_SERCOM->I2CM.DATA.reg = tx_buf[i++];
while(I2C_SERCOM->I2CM.SYNCBUSY.bit.SYSOP);
}
}
if(I2C_SERCOM->I2CM.INTFLAG.bit.SB)
{
if(i == (BUF_SIZE - 1))
{
I2C_SERCOM->I2CM.CTRLB.reg |= SERCOM_I2CM_CTRLB_ACKACT;
while(I2C_SERCOM->I2CM.SYNCBUSY.bit.SYSOP);
I2C_SERCOM->I2CM.CTRLB.bit.CMD = 0x3;
while(I2C_SERCOM->I2CM.SYNCBUSY.bit.SYSOP);
rx_buf[i++] = I2C_SERCOM->I2CM.DATA.reg;
while(I2C_SERCOM->I2CM.SYNCBUSY.bit.SYSOP);
rx_done = true;
}
else
{
I2C_SERCOM->I2CM.CTRLB.reg &= ~SERCOM_I2CM_CTRLB_ACKACT;
while(I2C_SERCOM->I2CM.SYNCBUSY.bit.SYSOP);
rx_buf[i++] = I2C_SERCOM->I2CM.DATA.reg;
while(I2C_SERCOM->I2CM.SYNCBUSY.bit.SYSOP);
I2C_SERCOM->I2CM.CTRLB.bit.CMD = 0x2;
while(I2C_SERCOM->I2CM.SYNCBUSY.bit.SYSOP);
}
}
}
void I2C_Init(void)
{
while(I2C_SERCOM->I2CM.SYNCBUSY.bit.ENABLE);
I2C_SERCOM->I2CM.CTRLA.bit.ENABLE = 0;
while(I2C_SERCOM->I2CM.SYNCBUSY.bit.SWRST);
/* Perform a software reset */
I2C_SERCOM->I2CM.CTRLA.bit.SWRST = 1;
/* Wait for synchronization */
while(I2C_SERCOM->I2CM.CTRLA.bit.SWRST);
/* Wait for synchronization */
while(I2C_SERCOM->I2CM.SYNCBUSY.bit.SWRST || I2C_SERCOM->I2CM.SYNCBUSY.bit.ENABLE);
//Using the WRCONFIG register to bulk configure both for being configured the SERCOM2 SDA and SCL pins
PORT->Group[I2C_SERCOM_PINS_PORT_GROUP].WRCONFIG.reg =
PORT_WRCONFIG_WRPINCFG| //Enables the configuration of PINCFG
PORT_WRCONFIG_WRPMUX | //Enables the configuration of the PMUX for the selected pins
PORT_WRCONFIG_PMUXEN | //Enables the PMUX for the pins
PORT_WRCONFIG_PMUX(I2C_SERCOM_PORT_PMUX) | //Bulk configuration for PMUX
PORT_WRCONFIG_PINMASK( I2C_SERCOM_SDA_PIN | I2C_SERCOM_SCL_PIN); //Selecting which pins are getting bulk configured
PM->APBCMASK.reg |= I2C_SERCOM_APBxMASK; //Enable the SERCOM under the PM
GCLK->CLKCTRL.reg = GCLK_CLKCTRL_ID(I2C_SERCOM_GCLK_ID_CORE) | //Provide necessary clocks to the peripheral
GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN(I2C_SERCOM_CLK_GEN);
I2C_SERCOM->I2CM.CTRLA.reg = SERCOM_I2CM_CTRLA_MODE_I2C_MASTER; //
I2C_SERCOM->I2CM.CTRLB.reg = SERCOM_I2CM_CTRLB_SMEN; //Configure I2C in SMART mode (will automatically ACK after reading buffer)
I2C_SERCOM->I2CM.CTRLA.bit.INACTOUT = SERCOM_I2CM_CTRLA_INACTOUT(0);
uint16_t BAUD_REG = ((float)Clockfreq / (float)(2 * Baudrate)) - 1;
I2C_SERCOM->I2CM.BAUD.bit.BAUD = BAUD_REG;
while (I2C_SERCOM->I2CM.SYNCBUSY.bit.ENABLE); //Wait for SYNCBUSY bit before enabling peripheral
I2C_SERCOM->I2CM.CTRLA.reg |= SERCOM_I2CS_CTRLA_ENABLE; //Enable the peripheral
}
bool i2c_write(uint8_t *data, int size)
{
I2C_SERCOM->I2CM.ADDR.reg = SERCOM_I2CM_ADDR_ADDR(GPS_ADR); //
while (0 == (I2C_SERCOM->I2CM.INTFLAG.reg & SERCOM_I2CM_INTFLAG_MB));
if (I2C_SERCOM->I2CM.STATUS.reg & SERCOM_I2CM_STATUS_RXNACK)
{
I2C_SERCOM->I2CM.CTRLB.reg |= SERCOM_I2CM_CTRLB_CMD(3);
return false;
}
for (int i = 0; i < size; i++)
{
I2C_SERCOM->I2CM.DATA.reg = data[i];
while (0 == (I2C_SERCOM->I2CM.INTFLAG.reg & SERCOM_I2CM_INTFLAG_MB));
if (I2C_SERCOM->I2CM.STATUS.reg & SERCOM_I2CM_STATUS_RXNACK)
{
I2C_SERCOM->I2CM.CTRLB.reg |= SERCOM_I2CM_CTRLB_CMD(3);
return false;
}
}
I2C_SERCOM->I2CM.CTRLB.reg |= SERCOM_I2CM_CTRLB_CMD(3);
return true;
}
bool i2c_read(uint8_t *data, int size)
{
I2C_SERCOM->I2CM.ADDR.reg = GPS_ADR | I2C_TRANSFER_READ;
while (0 == (I2C_SERCOM->I2CM.INTFLAG.reg & SERCOM_I2CM_INTFLAG_SB));
if (I2C_SERCOM->I2CM.STATUS.reg & SERCOM_I2CM_STATUS_RXNACK)
{
I2C_SERCOM->I2CM.CTRLB.reg |= SERCOM_I2CM_CTRLB_CMD(3);
//dbg_log("I2C: RXNACK during read (address)\r\n");
return false;
}
I2C_SERCOM->I2CM.CTRLB.reg &= ~SERCOM_I2CM_CTRLB_ACKACT;
for (int i = 0; i < size-1; i++)
{
data[i] = I2C_SERCOM->I2CM.DATA.reg;
while (0 == (I2C_SERCOM->I2CM.INTFLAG.reg & SERCOM_I2CM_INTFLAG_SB));
}
if (size)
{
I2C_SERCOM->I2CM.CTRLB.reg |= SERCOM_I2CM_CTRLB_ACKACT;
I2C_SERCOM->I2CM.CTRLB.reg |= SERCOM_I2CM_CTRLB_CMD(3);
data[size-1] = I2C_SERCOM->I2CM.DATA.reg;
}
return true;
}
void i2c_master_transaction(void)
{
i = 0;
I2C_SERCOM->I2CM.CTRLB.reg &= ~SERCOM_I2CM_CTRLB_ACKACT;
while(I2C_SERCOM->I2CM.SYNCBUSY.bit.SYSOP);
I2C_SERCOM->I2CM.ADDR.reg = (GPS_ADR << 1) | I2C_TRANSFER_WRITE;
while(!tx_done);
i = 0;
I2C_SERCOM->I2CM.CTRLB.reg &= ~SERCOM_I2CM_CTRLB_ACKACT;
while(I2C_SERCOM->I2CM.SYNCBUSY.bit.SYSOP);
I2C_SERCOM->I2CM.CTRLB.reg = (GPS_ADR << 1) | I2C_TRANSFER_READ;
while(!rx_done);
I2C_SERCOM->I2CM.INTENCLR.reg = SERCOM_I2CM_INTENCLR_MB | SERCOM_I2CM_INTENCLR_SB;
}
int main(void)
{
/* Initialize the SAM system */
SystemInit();
TMR_Init();
I2C_Init();
i2c_master_transaction();
//uint8_t buffer[256];
//uint8_t gpsreg = 0xFD;
/* Replace with your application code */
while (1)
{
i2c_write(gpsreg, 1);
i2c_read(gpsreg, 1);
}
}
>
