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SERIES 90, PM9005 OPERATING INSTRUCTIONS
(2704/2708 PERSONALITY MODULE)
2704 and 2708 PROMSs require a specialized programming sequence. This sequence causes the PM9005
personality module to operate in a manner different than other personality modules.
The programming characteristics of the 2704 and 2708 PROMs require that when any location is to be
programmed, all other locations must be programmed to prevent data loss. It is important to note that if
data is to be added to a partially programmed 2704 or 2708 the existing data must be reprogrammed when
the new data is added.
MULTI-PASS PROGRAMMING
The programming technique for the 2704 or 2708 specifies a fixed number of passes through all addresses
to guarantee programming of worse-case devices. Using the multi-pass technique the Series 90 performs
100 programming passes through all addresses. This operation requires just over 2 minutes for a 2708.
The required multi-pass programming is accomplished in PM9005 personality module by buffering all
data in a RAM memory. The relationship of the RAM memory to the COPY ROM and input devices is
shown below.
INPUT
DEVICES
MASTER
SOCKET
KEY
BOARD
TTY
PT
READER
~
"
~
"-
/
"'-'/
V
V
LAST ADDRESS (Buffer Full Signal)
. .
~
.n"
/
......
READ
VERIFY
f
CHECK
RAM
/
COpy
BUFFER
-+
PROM
' \ .0
PROG
DUPLICATE
~
PROM-RAM TRANSFER
The RAM buffer collcts the data to be programmed into the PROM. When the RAM buffer is full the data is
automatically transferred to the PROM by the multi-pass programming technique. The LAST ADDRESS
location of the RAM buffer is used as a signal to start the multi-pass programming.
LAST ADDRESS condition occurs when data is entered into the last address location of the RAM. THE
LAST ADDRESS is defined as either:
LAST ADDRESS for 2708 is 3FF
LAST ADDRESS for 2704 is 1 FF
TH E LAST ADDRESS must be programmed in order to transfer data from RAM to copy PROM.
1
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