LPC82x I2C Error

[tiagofernandes]

Hello,

I'm trying to use the I2C in the LPC82x but I have some troubles. I configure the micro as shown below, however when I'm trying to the the signal with osciloscope (read mode:digital signals) the signals (SDA and SCL) are always high. What I'm doing wrong?

/* Enable the clock to the Switch Matrix */
Chip_Clock_EnablePeriphClock(SYSCTL_CLOCK_SWM);
/* Connect the I2C_SDA and I2C_SCL signals to port pins(P0.10, P0.11) */
Chip_SWM_EnableFixedPin(SWM_FIXED_I2C0_SDA);
Chip_SWM_EnableFixedPin(SWM_FIXED_I2C0_SCL);
/* Enable standard mode/Fast mode for I2C pins */
Chip_IOCON_PinSetI2CMode(LPC_IOCON, IOCON_PIO10, PIN_I2CMODE_STDFAST);
Chip_IOCON_PinSetI2CMode(LPC_IOCON, IOCON_PIO11, PIN_I2CMODE_STDFAST);

/* Disable the clock to the Switch Matrix to save power */
Chip_Clock_DisablePeriphClock(SYSCTL_CLOCK_SWM);

Chip_I2C_Init(LPC_I2C0);
Chip_I2C_SetClockDiv(LPC_I2C0, 2);
Chip_I2CM_SetBusSpeed(LPC_I2C0, I2C_BITRATE);      //I2C_BITRATE=100kHz
Chip_I2CM_Enable(LPC_I2C0);

After this configurations I call a function to write to a slave device. Which configurations I'm doing worng or are missing?

Best Regards,

Tiago

[tiagofernandes]

Hello,

I think I resolve the problem with the resolution that I presented in I2C on LPC810/LPC812 . Now my problem is, after send the slave address I receive always Not Ack (supposed to receive Ack because the slave is connected and that's your address). I verify the slave's address (+RW bit) and it's correct, the slave is also connected. Anyone can help me?

Best regards,

Tiago

[Carlos_Mendoza]

Hi Tiago,

Your configuration in the code snippets above is correct, have you tried using the I2C LPCOpen examples as base for your application? Maybe you could take a look to the periph_i2cm_polling example.

Also, have you tried using a logic analyzer to make sure the correct address is being sent?

Thanks in advance for your response!

Best Regards,
Carlos Mendoza
Technical Support Engineer

[tiagofernandes]

Hello Carlos,

First of all thanks for the answer.
I not use the examples because they use functions of the ROM.
I think I could already solve the problem but I don't know how I do that, because I comment my code, test other part of the I2C, comment this part and uncommented the previous part and start work. Like you said I always have in my tests a logic analyzer to see the address and always its correct. 

Best Regards,

Tiago

[Carlos_Mendoza]

Hi Tiago,

Thanks for your response, is good to hear the problem was solved. Let us know if you have any other issue.

Best Regards!
Carlos Mendoza
Technical Support Engineer