PGA900: 1- wire communication question

Robert Eschbach

Part Number: PGA900

From my customer:

I’m trying to get the one wire interface to work with the PGA900 and am just in the beginning stages. On question immediately came up:

With the OWI read initialization command the memory page can be specified (such as data RAM), followed by one 8 bit data field for the address.

How can you specify an address in a 1KB data ram with only 8 bits?

over 4 years ago

0 Scott Cummins over 4 years ago

TI__Mastermind 31655 points

Hi Robert,

The SRAM is separated into pages. You first have to specify a page address in the DATARAM_PAGE_ADDR register, and then the 8bit address for the register you wish to access within that page.

Regards,

0 David Cutter over 4 years ago in reply to Scott Cummins

Prodigy 40 points

My problem now is that I just can't get OWI to respond at all. All I get is OWI_ERROR_STATUS_HI = 0x01, sync timing error. The sync pulses I send look perfect at 1,200 baud and match exactly the baud coming out of the UART baud rate generator. The voltage levels look excellent. The OWI activation pulse is recognized with no issued, the OWI interrupt routine is executing. OWI clock is enabled. Can anyone think of anything else I could be missing?

0 David Cutter over 4 years ago in reply to David Cutter

Prodigy 40 points

Found the problem. The Read Response command is a separate stand-alone command and needs it's own sync field. I was appending it to the Read Initialization command, which resulted in a sync error. Beginner's mistake

0 Scott Cummins over 4 years ago in reply to David Cutter

TI__Mastermind 31655 points

Hi David,

Thanks for updating with your findings!

Regards,

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PGA900: 1- wire communication question