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8051 Serial Rx Seems Stuck?

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Ivan
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Joined: 12/12/2017 - 23:44
8051 Serial Rx Seems Stuck?

Hello, 

I've been tasked with trying to debug someone's 8051 mcu program. The 8051 interfaces with a max232 serial chip to output and receive values from a keyboard and display messages to a computer monitor. The main problem arises when the program will stop responding to keyboard inputs and the same prompt for user input repeats indefinitely after entering any keyboard value. When I modified the program to output what character it thought it was receiving, I noticed strange results. When the program bugs out, it seems to output the same character even though other keys are being pressed. I'm new to the forums and I would like to ask what more information would help paint a clearer picture of my issue? I'm not so sure where the problem may lie. I've thought that it might be a max232 chip issue, or a buffer that gets "stuck". Could it be a stack overflow issue? I added a counter that increments at the beginning of of each function and decrements at the end of a function to track exactly how deep I am calling functions. It never goes above 3, yet the problem persists. Thanks in advance for any replies.

Hari Prasaath K
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Joined: 20/01/2015 - 23:56
8051 Keyboard

Hi,

Whether you have interfaced keyboard to the microcontroller using ps2 port or whether you are performing the normal serial interfacing operation. 

Check the below link for further info

https://www.engineersgarage.com/microcontroller/8051projects/interface-A...