Issue with serial communication

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theMainframer
Posts: 2
Joined: 29 Dec 2018, 04:13

Issue with serial communication

Post by theMainframer » 04 Mar 2019, 03:07

My Gigatron has an issue where the left arrow does not work on both the controller and the keyboard. Also, when I tested the keyboard many of the keys did not output their corresponding letter and some were even duplicates (I have two keys that output '7' for example). I checked for bad soldering, but I did not see any obvious problems. What are your opinions for what could be causing this?

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marcelk
Posts: 329
Joined: 13 May 2018, 08:26

Re: Issue with serial communication

Post by marcelk » 04 Mar 2019, 10:01

This would be the connection of the shift register U39 pin 1 to the data bus. It can be checked with a multimeter. For example verify that this pin makes a connection to U10 pin 9.

74HC595.jpeg
Game controller buttons to bus
74HC595.jpeg (270.47 KiB) Viewed 304 times

theMainframer
Posts: 2
Joined: 29 Dec 2018, 04:13

Re: Issue with serial communication

Post by theMainframer » 05 Mar 2019, 21:55

Thank you, that solved the problem.

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