CCS/MSP430F6659: msp430f6659

Hi Manoj,

Let me quickly recapture your issue here:

After reading data from your slave (PCA9505), your master (MSP430F6659) does not show the data you previously sent but wrong data. Is that correct?

First of all you could have a look at the I2C software examples we provide for MSP430 devices. You can use the TI Resource Explorer either in CCS or the online version of it, browse to your part and have a look at the software examples for I2C. Maybe that can give you a guidance.

Please also have a look at the Solutions to Common eUSCI and USCI Serial Communication Issues on MSP430 MCUs.

In case none of those help, please provide further details on your implementation for me to help you.

Thanks and best regards,

Britta

hi Britta,
Exactly correct After reading data from your slave (PCA9505), your master (MSP430F6659) does not show the data you previously sent but wrong data. I will see issue for serial communications on MSP430 and I@C examples for MSP430 Devices. If the problem will not solved, I will send my I2C code. Thank you for your support.

With Regards,
P M Manoj Kumar.

Hi Manoj,

did you have the time to check the I2C examples? Did it solve your issue?
If not please share some more details on your implementation and the error case you see.

Thanks and best regards,
Britta

Hi Britta,

I tried but still i am getting same problem. I will send my I2C module initialization and slave reading code to you.

with regards,

P M Manoj Kumar.

Hi Britta,

Here i am sending I2C initialization and reading from slave code.

1)

void I2Cinit(void)

{

UCD0CTL1 |= UCSWRST;   //ENABLE SW RESET

UCD0CTL0 | = UCMST | UCSYNC | UCMODE_3;  //I2C SYNC AND MASTER MODE SELECTION

UCD0CTL1 | = UCSSEL_1; //USE ACLK

UCBBR0 = 25;

UCBBR1 = 0;

UCB0CTL1  &= ~UCSWRST;   //INITIALIZE USCI STATE MACHINE

}

2)

unsigned char ReadFromI2CPort(unsigned char SlaveAddr, unsigned char OpRegAddr)

{



unsigned char ReadData = 0;

while(UCB0CTL1 & UCTXSTP);

UCB12CSA  =  SlaveAddr;

UCBCTL1 | = UCTR | UCTXSTT;

while( ! ( UCB0IFG  &  UCTXIFG ) );

UCB0TXBUF  =  OpRegAddr;

while( ! ( UCB0IFG  &  UCTXIFG ) );

UCB0CTL1  &=  ~UCTR;

UCBCTL1 | = UCTXSTT;

while( ! ( UCB0IFG  &  UCRXIFG ) );

ReadData  =  UCB0RXBUF;

UCBCTL1 | = UCTXSTP;

return ReadData;

}

with regards,

P M Manoj Kumar

Hi Bruce,

PCA9505 is configured as Output and PCA9505 GPIO's Connected to Relay Switches. And reading/writing Output Port Registers.

with regards,

P M Manoj Kumar.

Hi Manoj,

have you checked your communication with an oscilloscope?
What size are your pull-ups on on SDA/SCL?
Do you have long traces which add capacitance on SDA/SCL that could lead to round waveforms?
Have you checked lower communication speed?

Best regards,
Andre

Hi Andre,

I will look into above consideration, After that i will reply back.

With Regards,
P M Manoj Kumar.

Hi Manoj,

any update on this issue? I assume that the issue has been solved as you didn't reply back on this thread anymore.
Please verify the given answer and let me know if this thread can be closed.

Thanks and best regards,
Britta