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I have blogged about the Navigation Computer Display's Keyboard here. I was moving a 6821 PIA to its resting place and checked my Databooks where I found a pdf copy of the 6800 application manual. where they had a 4x4 keyboard interface. It was based around a row and column decoder but one cool thing added to it, and no diodes. And this has one more trick provided by the quad input NAND-Gate. Now an MCP23017 will work very nicely. It has interrupt outputs. But if you don't want to use this par ...
This is now round two. last night I wondered if I popped the MCP23017 or, is the scanner software bad? So the first this I did was to stick an MCP2327  on a breadboard and ran the scanner. It still said No I2C address found. As I relooked at the documentation and other websites I noticed that the device has a reset pin which is low-active, so without it connected to a pull-up it floats. This keeps the device in reset and nothing will work. Now the scanner is reporting I2C device at address ...
Well, I am working to get the Indicator done today or tomorrow, the slight tremors in my hands make Wire-Wrap a real pain. I will not get to a point where this will be buttoned-up, as there will be a lot of jumpers! I also have to trim down the interface board with my Dremel sander as it's not square to the mounted display board and the interconnect mounted on my interface vector board, which I thought was square, to begin with as Vector board has .1 by .1 hole spacing. Duh? Also when the displa ...
This picture on the left is just to remind you all of what I am trying to get working.  Each HDSP-2131 display has 24 pins that give you 48 pins to deal with. Now let us complicate the issue the pins come out on a 30-pin connector of which 4 are for power and ground. So now I have 28 pins for the interface. Other people have used similar displays ie  Wise Time with Arduino and others. Most of the implementations that I have seen use a Flip-Flop to load the characters, but why go to tha ...
Well, for starters there are problems with the Ardunio CAN bus library, as ANY node in the system can be a master or a slave. Currently, the Arduino CAN supports a SLAVE - MASTER, relationship. On the MCP2515_CAN module, you have the following connection on the header, plus outputs Hight and Low. So with what little time I have remaining. I just will be sending and receiving messages via the USB port using CANaerospace formatted messages. SIGNAL MODULE MEGA PIN ICSP Definition MOSI SI 51 4 Maste ...

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