uint8_t u8g_com_hw_i2c_fn(u8g_t *u8g, uint8_t msg, uint8_t arg_val, void *arg_ptr)
{
register uint8_t *ptr = arg_ptr;
switch(msg)
{
case U8G_COM_MSG_STOP:
break;
case U8G_COM_MSG_INIT:
init_i2c();
//I2C_WrReg(0x80, 0xAE);
//I2C_WrReg(0x80, 0x8D);
//I2C_WrReg(0x80, 0x14);
//I2C_WrReg(0x80, 0xAF);
u8g_MicroDelay();
break;
case U8G_COM_MSG_ADDRESS: /* define cmd (arg_val = 0) or data mode (arg_val = 1) */
if(arg_val == 0){
control = 0; //Send a Command (D/C# pin is low)
}
else{
control = 0x40; //send data
}
u8g_10MicroDelay();
break;
case U8G_COM_MSG_CHIP_SELECT:
break;
case U8G_COM_MSG_RESET:
break;
case U8G_COM_MSG_WRITE_BYTE:
I2C_WrReg(control, arg_val);
//u8g_i2c_start(0x78);
//u8g_i2c_send_byte(arg_val);
//u8g_i2c_stop();
u8g_MicroDelay();
break;
case U8G_COM_MSG_WRITE_SEQ:
case U8G_COM_MSG_WRITE_SEQ_P:
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_BUSY) == SET);
I2C_TransferHandling(I2C1, 0x78, 1, I2C_Reload_Mode, I2C_Generate_Start_Write);
//Ensure the transmit interrupted flag is set
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_TXIS) == RESET);
//Send the address of the register we wish to write to
I2C_SendData(I2C1, control);
//Ensure that the transfer complete reload flag is Set, essentially a standard
//TC flag
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_TCR) == RESET);
I2C_TransferHandling(I2C1, 0x78, arg_val+1, I2C_AutoEnd_Mode, I2C_No_StartStop);
//Again, wait until the transmit interrupted flag is set
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_TXIS) == RESET);
//Send the value you wish you write to the register
while( arg_val > 0 )
{
I2C_SendData(I2C1, *ptr++);
arg_val--;
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_TXIS) == RESET);
//Wait for the stop flag to be set indicating a stop condition has been sent
}
I2C_TransferHandling(I2C1, 0x78, 0, I2C_AutoEnd_Mode, I2C_Generate_Stop);
//while(I2C_GetFlagStatus(I2C1,I2C_FLAG_STOPF) == RESET);
//I2C_ClearFlag(I2C1, I2C_FLAG_STOPF);
delay_micro_seconds(100);
//u8g_MicroDelay();
break;
}
return 1;
}
//The main!
int main(void)
{
//Setup a systick interrupt every 1ms (1/1000 seconds)
SysTick_Config(SystemCoreClock/1000);
//Enable GPIOB clock, required for the I2C output
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOB, ENABLE);
//Enable the I2C peripheral clock
RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C2, ENABLE);
//Set the pins HMC_SDA and HMC_SCL as alternate function GPIO pins
GP.GPIO_Pin = HMC_SDA | HMC_SCL;
GP.GPIO_Mode = GPIO_Mode_AF;
GP.GPIO_OType = GPIO_OType_OD;
GP.GPIO_Speed = GPIO_Speed_Level_1;
GPIO_Init(HMC_GPIO, &GP);
//Configure the pins to the I2C AF
GPIO_PinAFConfig(HMC_GPIO, HMC_SDA_PS, HMC_PIN_AF);
GPIO_PinAFConfig(HMC_GPIO, HMC_SCL_PS, HMC_PIN_AF);
//Setup the I2C struct. The timing variable is acquired
//from the STM32F0 I2C timing calculator sheet. Pretty
//standard stuff really, its using the Analog filter
//to clean up any noisy edges (not really required though
//if you wish to disable it, you will need a different
//I2C_Timing value).
IT.I2C_Ack = I2C_Ack_Enable;
IT.I2C_AnalogFilter = I2C_AnalogFilter_Enable;
IT.I2C_DigitalFilter = 0;
IT.I2C_Mode = I2C_Mode_I2C;
IT.I2C_OwnAddress1 = 0xAB;
IT.I2C_Timing = 0x10805E89;
IT.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
I2C_Init(HMC_I2C, &IT);
I2C_Cmd(HMC_I2C, ENABLE);
//Write the configuration registers for the HMC5883L compass.
const uint8_t SmplAverage = 0b11; //Average 8 samples
const uint8_t OutputRate = 0b110; //Output at 75Hz (Why not!)
const uint8_t MeasurementCfg = 0b00; //We don't want any bias on the sensors
const uint8_t SnsrGain = 0b100; //A gain of 440LSb/Gauss, standard.
const uint8_t HighSpeedI2C = 0; //We want standard speed I2C.
const uint8_t SnsrMode = 0b00; //Continuous measurement mode
//Config 1 register
I2C_WrReg(R_Config1, (SmplAverage<<5)|(OutputRate<<3)|MeasurementCfg);
//Config 2 register
I2C_WrReg(R_Config2, (SnsrGain<<5));
//Mode register
I2C_WrReg(R_Mode, (HighSpeedI2C<<7)|SnsrMode);
//Give the sensor a breather before reading data!
Delay(10);
int8_t RecData[6] = {0,0,0,0,0,0};
int32_t XVal = 0, YVal = 0, ZVal = 0;
while(1)
{
//Read status register, waiting for the data ready flag
while(!(I2C_RdReg(R_Status, 0, 1) & 1));
//Receive 6 bytes of data from the value registers and store in
//RecData variable
I2C_RdReg(R_XRegister, &RecData[0], 6);
//Construct the words containing the value data!
//The HMC5883 is a little odd as it arranges its registers
//in the order X,Z,Y as opposed to what I suppose you'd
//expect from the normal order X,Y,Z.
XVal = (RecData[0]<<8) | RecData[1];
ZVal = (RecData[2]<<8) | RecData[3];
YVal = (RecData[4]<<8) | RecData[5];
}
}
