Re: [PARPORT] handshake with signals?


Mirek Kwasniak (mirek@zind.ikem.pwr.wroc.pl)
Tue, 3 Aug 1999 19:43:49 +0200


On Sat, Jul 31, 1999 at 12:01:11PM +0200, Uwe Klein wrote:
> hi,
> I got about 1.2 MByte in ECP Fifo/DMA ( 8Bit BusInteface ) mode
> outbound. This speed seems to be ISA Bus bound.
>
> While the FIFO is filled/emptied you will get a transfer every 500us
> which would suggest that the max ECP speed is about 2MByte.
>

Hi,

   Information
   Brief specifications for comparing the ECP parallel port (on late
   model Toshiba computers) and EPP parallel port hardware.

   EPP - Enhanced Parallel Port
     * 1-3 MB/sec
     * Asynchronous, interlocked, bi-directional communication - Half
       Duplex Operation
     * Targeted at register oriented type devices:
     * Network Adapters
     * Tape backup
     * CD-ROM
     * Master/slave architecture
     * Peripheral is polled for data
     * Supports peripheral interrupt
     * Supports two cycle types:
     * Address/command
     * Data
     * Symmetric Read/Write cycles
     * Hardware assisted handshaking/data transfer
     * Limited by I/O cycle capabilities of the implementation

   ECP - Extended Capability Port
     * 5 MB/Sec
     * Asynchronous, interlocked, bi-directional communication - Half
       Duplex Operation
     * Targeted at block oriented type devices:
     * Printers
     * Scanners
     * May have hardware support for RLE compression or decompression
       (optional)
     * Supports 2 cycle types:
     * Channel Address
     * Data
     * Peer to 'Peerish'
     * Peripheral may request the reverse channel, but the host controls
       the data transfer
     * Hardware assisted handshaking/data transfer
     * Implementations include DMA as well as programmed I/O PC interface
     * Data transfer rate limited by the DMA or I/O cycle capabilities of
       the implementation

Mirek

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