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1990-12-31
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98 lines
SetRamsey V1.02 by Nic Wilson
------------------------------
This program is freely distributable with no conditions
except that the program and this text file must remain
intact without any modification.
This program was written while I was testing the reason
why STATIC COLUMN MODE was not being set by the computer
as stated by the docs. This program allows you to test
the current settings of RAMSEY and change them if you wish.
If you try to set Static Column Mode or Burst Mode on, then
a test of your FAST RAM is done to ensure that it is infact
Static Column Mode (SCM) RAM.
REQUIREMENTS
------------
Amiga 3000, Kickstart V2.0 or V1.3
FUNCTION
--------
Allows manipulation of the RAMSEY ram controller modes in an
Amiga 3000.
USAGE
-----
SetRamsey STATICON, STATICOFF, BURSTOFF, BURSTON, WRAPON, WRAPOFF
REFRESHON n, REFRESHOFF
or SetRamsey ? Gives USAGE string
SetRamsey Gives current settings of RAMSEY and USAGE string.
STATICON - Tests and enables Static Column Mode if RAM passes test
STATICOFF - Turns Static Column Mode off
BURSTON - Tests RAM and turns SCM & BURST ON if RAM passes test
BURSTOFF - Turns Burst mode off
WRAPON - Allows all 4 longwords of a burst to take place
WRAPOFF - Burst will only continue A3,A2 are increasing
Burst will not be allowed to WRAP A3,A2=00
REFRESHON n - Sets refresh to value specified by n
n must equal 154, 238, 380
Defaults to 238 if n is not given.
REFRESHOFF - Turns refresh off
DO NOT USE UNLESS YOU HAVE A SPECIFIC REASON.
OTHERWISE IT WILL CAUSE A LOCK OR GURU.
TECHNICAL INFO
--------------
STATIC COLUMN MODE
This mode requires static column mode DRAMS. When ram is first accessed
RAS is held low after the cycle completes. This leaves the current RAM
page 'open' and the chip will act like static ram on this page. Any data
in this page can be accessed by changing the column address only. Since
the column address access time (tAA) is much less than the RAS access
time (tRAC), subsequent accesses to this page of data can be done faster.
As long as RAS is held low (10 usecs max) RAMSEY will allow the CPU to
access RAM on this page in only 3 clocks (16 & 25 MHZ).
BURST MODE
In this mode, RAMSEY will respond to *CBREQ (cache burst request) input
from the 68030 and allow burst accesses to FAST RAM. Each burst cycle
takes 2 clocks each (up to 3. Burst mode requires the use of static
column mode DRAMS.
WRAP MODE
RAMSEY allows for additional control over burst cycles via the WRAP option.
The 68030 will always request 4 longword (4 x 32 bit ) values during a
burst sequence. However if the initial longword is not aligned on a quad
long word boundary (A3,A2 not equal to 0,0), the 68030 will read data which
is behind the first data it asked for. Since it is less likely that this
data will actually be needed, RAMSEY can stop the burst sequence after the
data with A3,A2 = 1,1 is accessed.
All enquiries to
Nic Wilson Software
138d South Street
TOOWOOMBA QLD 4350
Phone (076) 358522 Work hours or FAX