Re: [PARPORT] ppdev and ECP

From: Julien (
Date: Tue Jul 24 2001 - 15:41:53 EDT

  • Next message: Philip Blundell: "[PARPORT] help print thru good old print port to hp5p (fwd)"

    Thanks for all your help

    Now the communication is working, I can read data from my Peripheral. I had problems with the software in my microcontroller.

    Now I'd like to use interrupts, but it doesnot work. I put "irq=auto", but select() never comes back. I can read data using read(), and I can read as many data as I want there is no problem.

    I have a logic analyzer, and there should be an IRQ because PeriphClk (nAck) goes low to initiate the transfer. How can I enable them ? I saw functions in the parport-lowlevel.txt so can I do it through ppdev or is that made automatically ?
    When the interrupts will be enabled, will the FIFO be used ? Can I set up the interrupt to occur only when the FIFO is full ?

    Thank you very much, I tried to find those answers on the net and on the documentation but I didnot found anything

    here is my dmesg :

    0x378: FIFO is 16 bytes
    0x378: writeIntrThreshold is 8
    0x378: readIntrThreshold is 8
    0x378: PWord is 8 bits
    0x378: Interrupts are ISA-Pulses
    0x378: ECP port cfgA=0x10 cfgB=0x00
    0x378: ECP settings irq=<none or set by other means> dma=<none or set by other means>
    parport0: PC-style at 0x378 (0x778), irq 7 [PCSPP,TRISTATE,COMPAT,ECP]
    parport0: cpp_daisy: aa5500ff87(b8)
    parport0: assign_addrs: aa5500ff87(b8)
    parport0: cpp_daisy: aa5500ff(18)
    parport0: assign_addrs: aa5500ff(18)
    parport_pc: Via 686A parallel port: io=0x378, irq=7
    ppdev: user-space parallel port driver

    I hope it is the last time I am asking you something.....

    PS : the speed is quite slow (about 30Ás for a byte, measured with my logic analyser) will the performances be better in interruptive mode ?

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