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Is RTSM A9 uart interrupt ok?

liang hua
Note: This was originally posted on 15th August 2011 at http://forums.arm.com

I run sample code 'SW012-SW-00000-r1p0-00rel0.zip' on RTSM CortexMPCore, uart interrupt does not generate after inputs a command.
The sample code has a uart console. Uart input is processed in interrupt. First command input is ok, but after that, input is hung up.
If not using uart interrput, input and output is ok.
  • Note: This was originally posted on 22nd August 2011 at http://forums.arm.com

    Hi ttfn,
    Thanks for your hint.
    But only enable FIFO can not work. Need more changes. Below is my solution.
    1. Enable FIFO and set interrupt mask to receive timeout.
    serial_init(CONSOLE, 38400, UART_PL011_LCRH_WLEN_8|UART_PL011_LCRH_FEN, UART_PL011_IMSC_RTIM);
    2. Modify cli_uart_handler,
    [s]    if (read32(UART_BASE + UART_PL01x_FR) & UART_PL01x_FR_RXFF) //RXFF is not handled correctly in SystemBench
    [/s]    if ((read32(UART_BASE + UART_PL01x_FR)&UART_PL01x_FR_RXFE) == 0)


  • Arm Employee Badge
    Note: This was originally posted on 16th August 2011 at http://forums.arm.com

    I remember trying this and hitting the same (or at least a similar) problem.  Will see if I kept me notes.
  • Arm Employee Badge
    Note: This was originally posted on 19th August 2011 at http://forums.arm.com

    Been tied up all week, and only just got a chance to look over my notes.

    So, what I remember is that there is a difference in the way the modelled UART and the real board.  The model sends an additional end of line character, which the ukernel doesn't seem to expect.  This lead to an overflow error in the UART.  With the vanilla code this meant that after the first UART based input you couldn't receive any more.  I fixed this by modifying the serial_init() function in ./arch/drivers/serial/serial.c so that the FIFO was enabled.  This prevented the overflow in the UART.
  • Arm Employee Badge
    Note: This was originally posted on 22nd August 2011 at http://forums.arm.com

    Ahh sorry, that bit didn't make it into my notes.