Sunday, April 25, 2010

PCF8574 Lives!

Well after spending a couple hours beating on it, turns out I had done the address jumpers backwards on the board.  So solder the dip switch as normal with "On" at the top, then flip it over to address it.  Here's a quick and dirty addressing table:

PCF8574AT:
A2
A1
A0
Address
0
0
0
56 (38h)
0
0
1
57 (39h)
0
1
0
58 (3Ah)
0
1
1
59 (3Bh)
1
0
0
60 (3Ch)
1
0
1
61 (3Dh)
1
1
0
62 (3Eh)
1
1
1
63 (3Fh)


The soldering is a bit messy as I had removed several components (including the PCF8574) while troubleshooting the addressing problem.  However here are the pics of MoboControl and the board connected to a fan.



Messily soldered board...


...and we have lift off!

3 comments:

  1. File HFLPFAdaptor17C.zip No longer accessible via
    Google groups site.
    Regards Eric VK5ZAG

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  2. Hi,
    Are you controlling the fan directly from the I/O board? Can it handle the current? Are you also using the I/O for your LPF control?
    Also, your Mobo control program shows LPF1 is at 57 and external 9574 also at I2C 57? Conflict? Correct? How do we address the I/O so it switches to proper filter on the LPF board?

    Thanks for the questions!
    Preston WJ2V

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  3. Hi Preston,

    Yes I am driving it thru the 8574. It's a 12v .15amp fan (I'm drawing a blank but I think it's limited to 500ma?) As for the switches, I'm trying to remember why I did that... you can change it (right now I'm not sure what it's set to as I had to box it up for an impending move...)

    -Mike
    KB1MTS

    ReplyDelete