MCP23017 Board assembly notes

http://www.blogger.com/blogger.g?blogID=1840459474737789074#editor/target=post;postID=7513279632388352607

Now I have completed the boring point to point soldering of the MCP23017 board.  I am using the incremental test driven approach in this part of hardware development project.

I started the power wiring, tested OK, then moved to the status indicator LED, tested OK, then move to the very bottom part of the circuit, the HC04.  Then I incremented upward, from HC04 to ULN2803, then to MCP23017 output side.  For the input side, I started with the  LVC245 and the edge connector.

Now I am going to solder the last bits, the RPi I2C to MCP23017, then I would then tested the output part.  I would leave the input part last, because I have never used the LVC245 before, so I worry that I might miss something important, and make newbie stupid mistakes here and there.

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