ENCAD 60e Service Manual page 33

Novajet PROe Series Service Manual
The normal method of downloading new firmware is to send the
printer a file of the new code. This requires using an appropriate
host utility. This can be done through either the serial or parallel
port. This method requires code to be running in the printer to
interpret the file.
If, for some reason, the EEPROM is blank or corrupt, there is an
additional step to download firmware to the printer. This additional
step requires a special J Tag Adapter to be placed between the
parallel cable and J16 on the printer's MPCB. It is a required step
that allows some registers and DRAM to be written to, based upon
commands sent through the port. See Firmware Downloading in
Chapter 3 for more information.
DRAM
DRAM is Dynamic Random Access Memory which provides tempo-
rary storage of the microprocessor calculation and input/output
data. It is also a faster type of memory then the Flash EEPROM.
Thats why the printer control program is also copied from the Flash
EEPROM to RAM, where it can be executed faster.
The printer also has two 72-pin 32-bit SIMM sockets for DRAM. The
printer is supplied with a SIMM of 8 Megabytes installed on the
MPCB. The following SIMM sizes are supported: 4MB (1Mx32),
8MB (2Mx32), 16MB (4Mx32), and 32MB (8Mx32.)
The SIMMs must have a minimum operating speed of 70ns, and
conform to JEDEC Standard 21-D release 4 or later. Remove the
Right Cover to install additional memory (see Chapter 6 for installa-
tion procedures.) Care must be taken when choosing a SIMM
module for the printer. Not all SIMM's on the market today will
work on the printer. It has to do with the "presence detect" signals
on pins 67 and 68 of the SIMM's. Not all SIMM manufactures use
these signals, so they disable them. Recommended SIMM's to be
used are listed in the User Guide.
Theory of Operation 33