PCF8574A: Reading from P0-P3

Danilo A.

Part Number: PCF8574A

Hi Team,

Our customer would like to read the inputs from P0-P3 of PCF8574A but can't figure out how to program the device. According to our customer,

I see that msp430g2xx3_uscib0_i2c_02.c (ti.com) says its an example for PCF8574A. But I can’t find the code where its reading inputs from P0-P3 in it. Does the data just appear in the UCB0RXBUF on its own?

I only need the parts specific to reading input from PCF8574A. Is it possible to get an example for one of the C2000 family devices?

Regards,

Danilo

over 2 years ago

0 Clemens Ladisch over 2 years ago

Guru 311370 points

That example program repeatedly starts a read transaction (setting UCTXSTT, with UCTR cleared).

The PCF8574A has only one register, so to read the inputs, just do a single I²C read without writing a register address.

0 Tyler Townsend over 2 years ago

TI__Mastermind 42323 points

Hi Danilo,

Please let me know if you have any more questions.

Regards,

Tyler

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PCF8574A: Reading from P0-P3