hoang@rex.cs.tulane.edu (Dzung Hoang) (09/02/89)
I just bought a used Microfazer printer buffer by Quadram. The seller
said it has a capacity of 64K, but when I opened buffer, I found 16 64K
RAM chips, indicating 128K. The circuit board is marked Microfazer
BUFFER 512K. The memory chips are socketed and in two banks of 8. I assume
that the board was designed to be expandable in terms of memory: by replacing
the 64K chips with 256K chips, I could have a 512K buffer. If this were so
then there should be some sort of configuration switches for the memory. The
only such possibility is an empty 24-pin socket labeled J3. Since I don't
have any documentation for the buffer, I have no idea how to use the socket
to configure the buffer.
If you have this buffer and the documentation would you please send me
information on the socket and memory configuration? Other operation
instructions would also be appreciated.
Dzung Hoang
--
-----------------------------------------------------------------------------
hoang@comus.cs.tulane.edu hoang@rex.cs.tulane.edu
hoang@comus.UUCP hoang@rex.UUCP
tulane!comus!hoang tulane!rex!hoang
-----------------------------------------------------------------------------henry@utzoo.uucp (Henry Spencer) (09/05/89)
In article <1078@rex.cs.tulane.edu> hoang@rex.UUCP (Dzung Hoang) writes: > I just bought a used Microfazer printer buffer by Quadram. The seller >said it has a capacity of 64K, but when I opened buffer, I found 16 64K >RAM chips, indicating 128K... That probably means 64KB of data buffering, plus working space for the processor. (I'm surprised that it would need another 64K, but it definitely will need some, over and above the rated capacity.) -- V7 /bin/mail source: 554 lines.| Henry Spencer at U of Toronto Zoology 1989 X.400 specs: 2200+ pages. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
greg@bilbo (Greg Wageman) (09/07/89)
In article <1989Sep5.162247.23447@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >In article <1078@rex.cs.tulane.edu> hoang@rex.UUCP (Dzung Hoang) writes: >> I just bought a used Microfazer printer buffer by Quadram. The seller >>said it has a capacity of 64K, but when I opened buffer, I found 16 64K >>RAM chips, indicating 128K... > >That probably means 64KB of data buffering, plus working space for the >processor. (I'm surprised that it would need another 64K, but it definitely >will need some, over and above the rated capacity.) Unless, of course, it uses a microcontroller with on-chip RAM and mask-programmed ROM (like the 8048, which it does). I got mine used, with no docs, from a computer surplus place. It seems to print its memory size on the connected printer if you hold down the pause/copy button when you reset the Quadram box. Reset again to stop print. Operation seems to be pretty straightforward. Plug it in to your printer and your computer. Mine has a switch to select between an external "wall-wart" supply (9VAC, 500ma), or supply from printer connection. (Unless you've got a heavy-duty supply in your printer with lots of spare capacity, use the external supply.) When your printer is on-line and ready, the "Error" light on the buffer should be off, and the "Ready" and "Copy" lights on. (The "Error" light on the front panel displays the status of the printer's "Error" line (paper out, ribbon out, etc.)). At this point, you can send data to the printer. If the job fits within the buffer, the "Copy" light remains lit and pressing the Pause/Copy switch will cause additional copies to be printed without your having to re-send the job. The "Copy" light will extinguish if the Quadram's memory fills up, indicating that there wasn't room for the whole job. The "Ready" light indicates the status of that line as seen by the computer. The "Reset" switch may be used to abort printing a job in progress and to clear the Quadram's memory. I believe the device is self-configuring; just plug in more memory and it should find it. (A standard memory-sizing trick is to read the byte at the top of each "page" of [potential] RAM, alter it, write it back, read it again and compare. If the program succeeds in changing the value, there's RAM there. If not, you've found the top of RAM at the previous page.) The empty socket is, I believe, for an external program EPROM, probably used for testing during manufacturing, since the on-chip program ROM is limited to, I think, 2K bytes. Greg Wageman DOMAIN: greg@sj.ate.slb.com Schlumberger Technologies UUCP: {uunet,decwrl,amdahl}!sjsca4!greg 1601 Technology Drive BIX: gwage San Jose, CA 95110-1397 CIS: 74016,352 (408) 437-5198 GEnie: G.WAGEMAN ------------------ Opinions expressed herein are solely the responsibility of the author.