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Last Post 05 May 2008 08:41 AM by  bphennesy@yahoo.com
Serial Port Access on the LH7A404
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bphennesy@yahoo.com
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02 May 2008 01:47 PM
    I am trying to run a very simple program that sends data out of the TX side of the port and then pauses and reads that data back on the RX side of the same port. The program works as expected on UART3 and I can see the data being sent by using an oscilloscope.

    The problem comes when I try the same thing on UART1. The scope shows that the data is being sent but my program waits forever and never sees it. I have looked at the control registers and find that UART1 is enabled and the infra-red option is disabled as it should be.

    Can anyone tell me what else must be set (or cleared) in order for this port to work correctly?
    mikea@logicpd.com
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    02 May 2008 03:56 PM
    Have you checked your pin muxing setup?

    CON:SIRD should be set to '1' to use as standard UART instead of '0'.

    Just fyi, we have all three ports working in the Windows CE BSP. They have all been tested and have been used by several customers in their shipping product.
    bphennesy@yahoo.com
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    05 May 2008 08:41 AM
    Yes, this register is set to 0x3 by default which disables infrared operation. I experimented with changing these values but doing so did not result in coorect operation.

    Something else I noticed was that the control register for UARTB has the UARTEN bit cleared after booting but works anyway. Reading through the documention I found that bit 3 (counting from 0) of the PINMUX register being enabled (i.e., set to 1) is what actually controls this port.

    I was hoping that UARTC had the same sort of condition!
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