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TCA9544A: Differences between this and PCA9544APWR

Tim Jameson
Prodigy 10 points
Part Number: TCA9544A
Other Parts Discussed in Thread: PCA9544A

Greetings Folks,

I am looking for interface differences between the TCA9544A, and the PCA9544APWR. Looking at the datasheets for these chips, they appear to be very similar. However, the PIC driver code I have for the PCA9544 has issues working with the TCA9544A.

PIC driver code follows:

I2C_Write_Start(addr, chan);
_asm // delay needed for proper read
nop
nop
_endasm
I2C_Write_Stop();

 

Thank you for your assistance,

Tim

  • 0
    TI__Genius 15345 points

    Hi Tim,

    Were you using the PCA9544 from NXP or TI? The TCA products are meant to be drop in replacements for their TI PCA counterparts. They generally have bug fixes and are cheaper due to improved manufacturing processes.

    Do you have a schematic for your device along with what address you are writing to in the code?

    The address for the TCA9544A is 1 1 1 0 A2 A1 A0.

    Best,

    Chris

  • 0 in reply to Chris Ayoub
    Prodigy 10 points

    Hi Chris,

    We had been using the TCA9544 from TI, and are looking to use the PCA9544 from TI. Here is the schematic portion:

    The address used is:

    #define SW_ADDRB 0xE8

    Thanks,

    Tim

  • 0 in reply to Tim Jameson
    TI__Genius 15345 points

    Hi Tim,

    Can you send over the code for I2C_Write_Start()? Is there a reason why you are using the older version of the device. In theory these devices are the same but the TCA devices did fix many bugs that were found on their PCA counterparts. The biggest problem with going backwards is that the voltage rating of the PCA9544A is not as wide 2.3V-5V.

    Can you also send the pull up voltages of the SDA/SCL lines on either side of the device, along with the VCC voltage?

    Best,

    Chris