New Contributor
New ContributorHello Sheng,
I try to be more clear describing the problem we are facing.
Referring to the 16550 IP we are using the Stick Parity function (par 10.2) either in Tx either in Rx.
In our design we want to stick the parity to “1” for some Tx data and to “0” for all the other Tx data.
On the receiver side we have two Uart in parallel. The first configured with stick parity fixed to “0” and the second with stick parity fixed to “1”
In the first Uart the stick the parity set to “0”. We want to store only the received data with stick parity fixed by the Tx Uart to “1” (not related to data bits value) and discard all received data with stick parity fixed by the Tx Uart to “0” (LSR bit 2).
In the second Uart the stick the parity set to “1”. We want to store only the received data with stick parity fixed by the Tx Uart to “0” (not related to data bits value) and discard all received data with stick parity fixed by the Tx Uart to “1” (LSR bit 2).
In detail when I configure the Stick Parity to "0" on the Receiver Uart, I assume that the parity bit of the received data will generate a parity error in the LSR register (bit 2="1") only if the received data has the parity bit ="1" independently by the value of the data bits ( not calculated but stick to the programmed value in the LCR register)
In the following our test bench with two 16550:
In our test the second Uart receive the data in polling mode reading and storing the LSR register to check the LSR Bit0 (DR) to find if a new data is available.
If a receive data is ready, we check the in the stored LSR register the bit 2 (PE) that should be set to "1" for each received data (reset automatically to "0" after the reading of LSR register).
In our test we see that the LSR register bit 2 (PE) sometimes is "0" and sometimes is “1” independently from the stick parity programmed in the receiver Uart.
Can you check our test and support us to use the stick parity function in the receiver?
