TDA4VM: RTC MCP79410

Shine,

PMIC RTC(tps6594) is already enabled by default in 9.1 SDK. You can use that for any RTC features. Are you looking specifically for MCP79410 RTC?

- Keerthy

No, i do not care about tps6594. I'm working with mcp79410.

I want to read/write registers using i2cget/i2cset，but it shows "Error: Read Failed" "Error: Write Failed".
I also trying to read/write tca6416(i2c 7bit address is 0x20), it shows the same Error message.

I used oscilloscope to capture the clock of i2c-0 at R20，there is no clock.

want to know what's wrong? 

sincerely thanks

Hi Xi,

Couple of question before we get deeper:

• Is this a custom board or TI EVM?
• Share the output of the command "dmesg | grep i2c'
  The above command will show the i2c instance number of MAIN_I2C0.
• We need to use that bus number to initialize RTC.

- Keerthy

Hi Keerthy J,

1. TI EVM 

2. 

Thanks

Hi Xi,

The index for MAIN_I2C0 is '1' from your log.

Please try: i2cset -y 1 etc.

- Keerthy

Hi Keerthy，
Thanks for your help, I can move on now.

Still have a question, when power on why " rtc-ds1307 1-006f: hctosys: unable to read the hardware clock"?

There is not backup battery on the board, is that the reason?

Hi Xi,

This does not look to be due to backup battery. Are you now able to see RTC ticking?
Can you read the time? I am unable to assess the impact of the hardware clock error.
Is the RTC working fine now?

- Keerthy

Hi Keerthy,

The RTC seems work fine, but i don't have a backup battery, can't tell whether it works ok when power down and power up.

Thanks a lot for your reply.