DVR1 V1.50

Three changes were made in V1.50 since V1.49:

- If you are monitoring the power-up memory test from a computer
  or serial terminal, you will see the progress dots be printed
  8 times as fast.  This makes it easier to see if it is still
  running.

- After each reset, a message indicating that you can press 'H'
  for a menu of available commands is now sent out of the serial
  port rather than the menu itself.  This keeps the results of
  the memory test from scrolling off of the screen.

- A command was added that lets the controller interrupt a track
  that is currently playing.  This is used by the RLC-2 V4.25
  software to support polite DVR messages that switch to CW if
  you key up during them.

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                            DVR1 V1.49

V1.46 was the original release of the DVR software.  If you are 
currently using it, there is no reason to upgrade to V1.49.  Some 
people experienced problems with noise from their DRAM's 
interfering with the operation of the DVR1, causing the power on 
memory test to fail or not even begin.  So in V1.49 a wait state 
was added to the DRAM access.  This seems to eliminate the noise 
problem for some simms that otherwise fail.  There is no 
functional difference between V1.46 and V1.49.  If you experience 
problems with your simms even with V1.49, and your serial number 
is 016 or lower, contact us for information about adding 
additional bypass capacitors.

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This zip file contains the files needed to burn your own eproms for
the DVR1.  There are four separate versions, one for each possible
memory configuration.  You must use the proper version to make full
use of the memory you have installed.  The filenames begin with YxZ...
where y is the number of simms (2 or 4) and Z is the size of each
simm in megabytes (1 or 4).  The total amount of memory is obviously
Y times Z, and the total amount of record time is about two minutes
per megabyte.  You will need to burn two roms, one for the
high byte and one for the low byte.  The filenames end in H or L to
indicate high byte or low byte.  If you forget which socket in the
DVR is which, the socket closest to the connectors is the low byte.

Each *.bin file should be loaded into an eprom programmer as 
a binary file with no offset and burned into a 27C010 or 27C001 
eprom.  Note that only the first few kilobytes of the eprom will 
have any data in it - this is normal.

The V1.50 checksums are:

Memory 
Configuration          High (Even) Prom       Low (Odd) Prom
2x1                    7977                   E408
2x4                    7A43                   E591
4x1                    7834                   E8AB
4x4                    765C                   EF87

If you have any questions or problems, please contact us.

Steve Strobel
Link Communications, Inc.
steve@link-comm.com
http://www.link-comm.com
(406) 482-7515
(406) 482-7547 fax