From: ralph@swmerc.rain.com (Ralph Merwin) Subject: Re: DMA on PC motherboards Date: 19 Dec 1992 16:20:22 GMT
In article <19801@ksr.com> zdenek@ksr.com (Zdenek Radouch) writes:
>I need a new motherboard (probably 386DX-40) and I have heard rumors
>that some motherboards are having timing problems when supporting DMA
>transfers mastered by some controllers (for example transfers done by
>the Adaptec 1542).
>
>I am looking for the following info:
>
>1. Are there known problems with a particular MFG/board?
>2. Is there any way to test this using Adaptec 1542 under DOS?
OK, now that the motherboard issue has been hashed-out, we can get on to
the second part of the question - actually testing the DMA capability.
The Adaptec controller has a DMA transfer speed test in it's BIOS. Jumper
the DMA speed on the board for the slowest setting (J5, jumpers 12 and 13),
boot DOS (from floppy!), invoke 'debug', and type 'g=DC00:9' (the DC00 value
depends in the BIOS base address jumpers).
You'll get a signon from the DMA test with instructions. If the test works,
rejumper to the next faster speed and retest. After testing all four speeds,
jumper the board for the fastest speed that passed the test. I've seen some
motherboards that had problems at intermediate speeds but worked at higher
speeds.
Ralph
-- ======== DOS Windows = The worst plague ever let loose upon humans ======== Ralph Merwin ralph@swmerc.rain.com 503-526-8647