USI I2C Library for MSP430 LaunchPad

Hi Andreas,

all you need to know is written in the App Note that comes with the code: http://www.ti.com/litv/pdf/slaa368a

Don't forget to add external Pull-Up resistors.
In additon, you may want to have a look at this app notes too: http://focus.ti.com/mcu/docs/litabsmultiplefilelist.tsp?sectionId=96&tabId=1502&literatureNumber=slaa208a&docCategoryId=1&familyId=342, http://focus.ti.com/mcu/docs/litabsmultiplefilelist.tsp?sectionId=96&tabId=1502&literatureNumber=slaa383&docCategoryId=1&familyId=342, http://focus.ti.com/mcu/docs/litabsmultiplefilelist.tsp?sectionId=96&tabId=1502&literatureNumber=slaa382&docCategoryId=1&familyId=342.

Another nice reading is here: http://jbremnant.wordpress.com/2011/01/03/nokia-lcd-wiinunchuck-with-msp430/ (interfacing Nintendo Nunchuck with MSP430 via I2C).

Rgds
aBUGSworstnightmare

Dear aBUGSworstnightmare,

I tried this part of the example with and I/O Expander (PCF8574) and I noticed that the program executes all lines but it didn't send anything  via IIC bus.

I would like to know if I made a mistake in this code.

Thanks for your advice,

Andres Rada.

#include<msp430g2231.h>

#include "USI_I2CMaster.h"

unsigned char TxData0[] = {8};

int StatusCallback(unsigned char c);  

void main(void)

{

  int i;

  WDTCTL = WDTPW+WDTHOLD;                   // Stop watchdog

  if (CALBC1_1MHZ ==0xFF || CALDCO_1MHZ == 0xFF)                                     

  {  

    while(1);                               // If calibration constants erased

                                            // do not load, trap CPU!!

  } 

  BCSCTL1 = CALBC1_1MHZ;                    // Load DCO constants

  DCOCTL = CALDCO_1MHZ;

  P1DIR |= 0x01;                            // P1.0 as output (LED)

  P1OUT = 0x00;

  /* Initialize USI module, clock ~ SMCLK/128 */

  TI_USI_I2C_MasterInit(USIDIV_7+USISSEL_2+USICKPL, StatusCallback); 

  /* Acknowledge polling function - LED blinks continuously until slave device 

  provides an ACK 

  TI_USI_I2CSelect(unsigned char SlaveAddress) */

  while(TI_USI_I2CSelect(0x20))

  { 

    P1OUT ^= 0x01;                          // Toggle LED

    for (i = 0; i < 0x3000; i++);           // Delay

  }

  P1OUT =0;                                 // Slave acknowledged, LED off

  /* Transmit data to the EEPROM device, prefixed by page address 0x01 

   TI_USI_I2CWrite(SlaveAddress, Length, Multi, TxData) */

  __disable_interrupt();

  TI_USI_I2CWrite(0x20,1,0,TxData0);

  __bis_SR_register(LPM0_bits + GIE);

  /* Acknowledge polling function - loops continuously until slave device 

  provides an ACK */

  while(TI_USI_I2CSelect(0x20));              

  /* This function can be used to end any open I2C transaction.

  Use only if I2C transaction was left open previously by setting stop

  condition bit =1 */

  TI_USI_I2CStop();                          

  P1OUT |= 0x01;                            // data valid, LED on

  while(1);                                 // program ends here

} 

int StatusCallback(unsigned char c)

{

  return TI_USI_EXIT_LPM;                   // Exit active for next transfer

}

I don't see the port being configured for USI control by settign the appropriate bits in PxSEL.
Is it done in the I2C init funciton, and if so, does this function use constants you need to adjust to the exact MSP you're using?

On different MSPs, the USI signals are routed to different port pins and therefore need different port initialization in addition to the USI module itself. (this applies to every hardware module with I/O funcitonality)

I'm into the same problem with EEPROM At24c02.I'm also not getting the o/p(on reading the EEPROm ;Nothing is writtem their ).It is very urgent please rply asap.I have also removed the jumper 5 but even after this it is not working.

#include

.

Did you solve the problem? I have same problem here

The same problem here. I got a msp430f2002 and got the same behavior. I ordered about 5 msp430 chips and all of the use USI. I have only tested two without luck. Anybody out there that can explain this to us??

I am new in MSP430 world. Appreciate if someone point me to a link where I can get the I2C USI library for the MSP430G2332. I could not find it with CCS V5.3. Thanks

Alimul,

maybe this can help you:

http://processors.wiki.ti.com/index.php/I2C_Communication_with_USI_Module