Ignore:
Timestamp:
Dec 20, 1995, 3:39:19 PM (26 years ago)
Author:
Joel Sherrill <joel.sherrill@…>
Branches:
4.10, 4.11, 4.8, 4.9, 5, master
Children:
c64e4ed4
Parents:
4442d21c
Message:

changes remerged after lost in disk crash -- recovered from snapshot, partially recovered working tree, etc

File:
1 edited

Legend:

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  • c/src/lib/libbsp/m68k/mvme162/README

    r4442d21c r5c491aef  
    2828to follow the future RTEMS versions. I will do my best to provide
    2929whatever support I can afford time-wise.
     30
     31MVME162FX and DMA on the IP bus
     32-------------------------------
     33
     34From Eric Vaitl <eric@viasat.com>:
     35
     36If you have any customers that will be using the 162FX, tell them to
     37be careful. The main difference between the 162 and the 162FX is DMA
     38on the IP bus. I spent over a month trying to write a DMA HDLC driver
     39for GreenSprings IP-MP and couldn't get it to work. I talked to some
     40people at GreenSprings, and they agreed that there really is no way to
     41get DMA to work unless you know the size of the packets in advance.
     42Once the IP2 chip DMA controller is given the character count and
     43enabled, it doesn't accept further commands until all of the
     44characters have arrived. The only way to terminate a DMA transfer
     45prematurely is by raising DMAEND* during the last read. None of the IP
     46modules that I know of are currently able to do that. GreenSprings is
     47working on the problem, but nothing is going to available for a few
     48months.
    3049
    3150Installation
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