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How to find Register values for Uart operations

Uart 16550 register values after wrting / reading operation


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New User

Joined: 12 Dec 2011
Posts: 1

Dec 12, 2011 7:07 pm

Hello there I am trying to analyze this datasheet and find out the logic behind the working of various registers of UART

I am referring to specific UART - exar 788 and I would like to know how the logic is implemented.I have read the datasheet and I am trying to deduce the following

Read address offset 0x2 (ISR register), the value should be 0x1
Write 0x1 to address offset 0x2
Read address offset 0x2, the value should be 0xC1

Write 0x55 to THR ---- This should send data on the TX pin.
After a few seconds, can you read the status of the LSR register? Under normal conditions, the LSR register should be 0x60.
If it is 0x00, then the data is not being transmitted.

Write 0x40 to LCR --- This will send a break and force the TX pin low.


Here is the link to the datasheet please let me know as to how this would work

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