Difference between revisions of "AMRAM2"
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Revision as of 09:50, 27 August 2011
AMRAM2 is a ROM board from Silicon Systems.
The AMRAM has two PCBs sitting on top of each other, joined with a rigid connector.
On the bottom is passthrough for other expansion connectors and a 3V square lithium battery. (The exact replacement battery (40LF220 SAFT Memoguard 3.0V Lithium Encapsulated Cell) is expensive @ £19.49 each. It *is* possible to fit a PC CMOS compatible lithium battery (CR2032) and holder, but it's not as neat and there is not a lot of space between the two pcb boards of the Amram)
On the top, 32K RAM (contents are held by lithium battery so can survive a reset or power off), which can be programmed like ROM and occupies two ROM positions (1 and 2) and also sockets for expansion ROMs 3,4,5 and 6.
There is a bank of DIP switches to enable/disable ROM slots, a switch to enable/disable writes to 32K RAM (left side of top pcb), a LED to indicate RAM is ready to write and a switch to reset computer (right side of top pcb).
It seems the first few batches of these were distributed without boxes, so you had to provide your own. A suitable box can be made from a "General purpose ABS Enclosure" which is a black plastic box designed for electronics. This is the type of box shown in the picture.
Came with software to program it.
This came after the AMRAM which was 16K ram on a board which could be programmed and which occupied ROM slot 5. More details when I can find them in my documents.
Details of battery in AMRAM 2:
40LF220 SAFT Memoguard 3.0V Lithium Encapsulated Cell
Type: Lithium Manganese Dioxide. Voltage: 3.0 V. Height: 28 mm. Width: 25.4 mm. Thickness: 6.7 mm.
Technical
Documentation states to use port FBF0 to write to the AMRAM2. This is advised to avoid clashing with other hardware. I tested various I/O addresses and came to this port decoding:
A15-A0: xxxx10111111xxxx
When writing data only bit 0 of the data is significant all other bits are ignored. If bit 0 is 1, then AMRAM is activated and writing to it's RAM is possible. If bit is 0, then AMRAM is not active.
Pictures
Amram2 in pieces
Amram2 PCBs together (also shows top pcb)
Amram 2 bottom PCB (top)
Amram 2 bottom PCB (underneath)
Amram 2 top PCB (underneath)
Download
Amram 2 user manual: File:Amram2.pdf
