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Logitech (http://www.logitech.com/) provides some information about
their scanner boards. Currently, there are 8 (1) different boards. You
can identify your board using the P/N printed on the board.

SCANMAN 32/256 hardware:

Base: 0x280, 0x2A0, 0x330 0x0340

To communicate with the internal registers of the SCANMAN 32/256
hardware, you have to write the register number in port Base+0. Then
you can read or write the content of this register through port
Base+1. The general status of the device can be obtained by reading
port Base+0.


Base+0:
 W: internal register number
 R: status as follow

     +-+-+-+-+-+-+-+-+
     |7|6|5|4|3|2|1|0|  <- Bit number
     +-+-+-+-+-+-+-+-+
                |
                +----- 1 = scanner ready

Base+1:
  R/W: read/write contents of register selected through Base+0.

Possible registers:

REG NO   DESCRIPTION 
   0     general settings

         +-+-+-+-+-+-+-+-+
         |7|6|5|4|3|2|1|0|  <- Bit number
         +-+-+-+-+-+-+-+-+
                        |
                        +- 1 = light on

   3     IRQ/DMA settings

         +-+-+-+-+-+-+-+-+
         |7|6|5|4|3|2|1|0|  <- Bit number
         +-+-+-+-+-+-+-+-+
          | | | | | | | |
          | | | | | +-+-+- IRQ no:   1 = IRQ 3
          | | | | |                  2 = IRQ 4
          | | | | |                  3 = IRQ 5
          | | | | |                  4 = IRQ 2/9
          | | | | |                  5 = IRQ 7
          | | | | |                  6 = IRQ 11
          | | | | |                  7 = IRQ 12
          | | | | |                  (Don't know if 0 is a legal value.)
          | | | | +------- 1 = IRQ enable
          | +-+-+--------- DMA no:   1 = DMA channel 1
          |                          3 = DMA channel 3
          |                          5 = DMA channel 5
          |                          6 = DMA channel 6
          |                          7 = DMA channel 7
          |                          (Don't know if 0/2 are legal values.)
          +--------------- 1 = DMA enable

   5     ???

         +-+-+-+-+-+-+-+-+
         |7|6|5|4|3|2|1|0|  <- Bit number
         +-+-+-+-+-+-+-+-+
              | |
              +-+--------- type of scanner head: 1 = P/N 860008
                                                 3 = P/N 860013

   8     low byte of value 'bytes per line' 

   9     high byte of value 'bytes per line' 

  16     position of hardware switches

         +-+-+-+-+-+-+-+-+
         |7|6|5|4|3|2|1|0|  <- Bit number
         +-+-+-+-+-+-+-+-+
            | |       | |
            | |       +-+- no of bits per pixel: 0 = 8 bpp
            | |                                  1 = 6 bpp
            | |                                  2 = 4 bpp
            | |                                  3 = 1 bpp
            +-+----------- resolution in DPI:    0 = 400 DPI
                                                 1 = 300 DPI
                                                 2 = 200 DPI
                                                 3 = 100 DPI

  17     ??? scanner head attachment

         +-+-+-+-+-+-+-+-+
         |7|6|5|4|3|2|1|0|  <- Bit number
         +-+-+-+-+-+-+-+-+
                        |
                        +- 1 = scanner head attached      
