MCP23017 interface

Questions on control of serial busses
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YahooArchive
Posts: 1463
Joined: Fri Oct 19, 2012 5:11 am

MCP23017 interface

Post by YahooArchive » Tue Jan 29, 2013 2:28 am

Just a little more info.

I connected a MCP 23017 I2C chip to an armExpress board using pins 9 and
10 of the armExpress as clock and data. The program sets the data
direction register to output on bit 0 of port A and I have an led
connected in a sink circuit to that pin. Comments in the program detail
the connections, however I'm working on generating a schematic which
I'll also upload if I'm successful.
schemmcp23017.jpg
schemmcp23017.jpg (45.6 KiB) Viewed 3621 times
I hope this will help anyone else trying to interface that part to the
armExpress.



Jim.
Attachments
i2c(1).bas
MCP23017 program in BASIC
(4.64 KiB) Downloaded 209 times



YahooArchive
Posts: 1463
Joined: Fri Oct 19, 2012 5:11 am

Re: MCP23017 interface

Post by YahooArchive » Tue Jan 29, 2013 2:28 am

I've uploaded the schematic. Note three things.

1. It's hand drawn. I'm very frustrated with schematic drawing software.
2. I flunked 8th grade art. The teacher asked me (seriously) might I
not be a better candidate for shop class?
3. I think it's correct, but there might be an error or two.
4. I hate cad tools. They make life harder not easier! ( I know I said
3 but I had to get that one out there. I'm a EE that fell in love with
software and abandoned HW early on and am now being dragged kicking and
screaming back, ;) )

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