hi, everyone.
My project is to send and receive 1 Byte to communicate with one MSP430 through I2C Communication.
I have configurated UCB0 I2C(P3.1,P3.2, Master), UCB1 I2C(P3.7, P5.4), transmission speed at 400Kbps and SMCLK at 1MHz.
I have coded with driverlib of CCS.
It was working. But there are problems.
Blue is I2C_SDA and Yellow is I2C_SCL.
1) Frequency of SCL is 203.2KHz. I think the I2C_SCL should come close to 400KHZ. Because I set up 400Kbps.
USCI_B_I2C_initMasterParam I2cParam0 = {0,}; I2cParam0.selectClockSource = USCI_B_I2C_CLOCKSOURCE_SMCLK; I2cParam0.i2cClk = UCS_getSMCLK(); I2cParam0.dataRate = USCI_B_I2C_SET_DATA_RATE_400KBPS; USCI_B_I2C_initMaster(USCI_B0_BASE, &I2cParam0);
2) What does 1bit mean between Data Address and NACK ?
3) Is the NACK data signal normally this short? The NACK value could not be maintained for 1 clock.
This is my code.
#include <MSP430.h>
#include <MSP430F5xx_6xx/driverlib.h>
uint8_t transmitData = 0x52;
uint8_t receiveData;
/**
* main.c
*/
void main(void)
{
WDT_A_hold(WDT_A_BASE);// stop watchdog timer
initGPIO();
initClock();
initI2C();
__bis_SR_register(GIE);
while(1)
{
USCI_B_I2C_masterSendSingleByte(USCI_B0_BASE, transmitData);
while(USCI_B_I2C_isBusBusy(USCI_B0_BASE));
//__delay_cycles(50);
transmitData++;
}
}
#pragma vector = USCI_B1_VECTOR
__interrupt void USCI_B1_ISR(void)
{
switch(__even_in_range(UCB1IV, 0x0A)){
case 0x0A:
receiveData = USCI_B_I2C_slaveGetData(USCI_B1_BASE);
break;
default: //__never_executed();
break;
}
}
#include <MSP430F5xx_6xx/driverlib.h>
// Clock
#define XT1CLK_HZ 32768
#define XT2CLK_HZ 32768
#define DESIREDMCLK_KHZ 1000
#define MCLKXT1CLKRATIO DESIREDMCLK_KHZ/(XT1CLK_HZ/1024)
// I2C Slave
#define SLAVEADDRESS 0x51
uint32_t myACLK, mySMCLK, myMCLK;
void initGPIO(void)
{
//Configurate oscillator
GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P7, GPIO_PIN0 + GPIO_PIN1);
//Configurate I2C
GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P3, GPIO_PIN1 + GPIO_PIN2 + GPIO_PIN7);
GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P5, GPIO_PIN4);
//Configurate SMCLK
//GPIO_setAsPeripheralModuleFunctionOutputPin(GPIO_PORT_P11, GPIO_PIN2);
}
void initClock(void)
{
PMM_setVCore(PMM_CORE_LEVEL_3);
UCS_setExternalClockSource(XT1CLK_HZ, XT2CLK_HZ);
UCS_turnOnLFXT1(XT1DRIVE_0, XCAP_3);
UCS_initClockSignal(UCS_ACLK, UCS_XT1CLK_SELECT, UCS_CLOCK_DIVIDER_1);
//Configurate FLL
UCS_initClockSignal(UCS_FLLREF, UCS_XT1CLK_SELECT, UCS_CLOCK_DIVIDER_1);
UCS_initFLL(DESIREDMCLK_KHZ, MCLKXT1CLKRATIO);
myACLK = UCS_getACLK();
mySMCLK = UCS_getSMCLK();
myMCLK = UCS_getMCLK();
}
void initI2C(void)
{
USCI_B_I2C_initMasterParam I2cParam0 = {0,};
I2cParam0.selectClockSource = USCI_B_I2C_CLOCKSOURCE_SMCLK;
I2cParam0.i2cClk = UCS_getSMCLK();
I2cParam0.dataRate = USCI_B_I2C_SET_DATA_RATE_400KBPS;
USCI_B_I2C_initMaster(USCI_B0_BASE, &I2cParam0);
USCI_B_I2C_initSlave(USCI_B1_BASE, SLAVEADDRESS);
USCI_B_I2C_setSlaveAddress(USCI_B0_BASE, SLAVEADDRESS);
USCI_B_I2C_setMode(USCI_B0_BASE, USCI_B_I2C_TRANSMIT_MODE);
USCI_B_I2C_setMode(USCI_B1_BASE, USCI_B_I2C_RECEIVE_MODE);
USCI_B_I2C_enable(USCI_B0_BASE);
USCI_B_I2C_enable(USCI_B1_BASE);
USCI_B_I2C_clearInterrupt(USCI_B0_BASE, USCI_B_I2C_TRANSMIT_INTERRUPT);
USCI_B_I2C_clearInterrupt(USCI_B1_BASE, USCI_B_I2C_RECEIVE_INTERRUPT);
USCI_B_I2C_enableInterrupt(USCI_B0_BASE, USCI_B_I2C_TRANSMIT_INTERRUPT);
USCI_B_I2C_enableInterrupt(USCI_B1_BASE, USCI_B_I2C_RECEIVE_INTERRUPT);
}