Filter
Top Products
Theory of Operation 2-9
NovaJet 500/630/700 Series Service Manual
THEORY OF
OPERATION
The system firmware is stored in Flash EEPROM. The Flash
EEPROM allows the firmware to be upgraded by downloading the files
containing the new firmware. It can be erased and reprogrammed
more than 10,000 times. The term “Flash” means that bytes cannot be
individually erased. A block or the whole device is erased at the same
time and the block or whole device is then reprogrammed.
The normal method of downloading new firmware is to send the unit
the files containing the code using either the GO.EXE utility or print-
ing the file to the unit. This requires using an appropriate host utility
and can be done through the serial port (for Macintosh users) or the
parallel port (for PC users). See Firmware Downloading in Chapter 3
for the procedures.
DRAM
DRAM is Dynamic Random Access Memory which provides temporary
storage of the microprocessor calculation and input/output data. It is
also a faster type of memory then the Flash EEPROM. That’s 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 installed on the MPWA. The SIMM
size for the 500 series is 8 Megabyte and for the 630/700 series is 32
Megabyte. The following SIMM sizes are supported: 4MB (1Mx32),
8MB (2Mx32), 16MB (4Mx32), 32MB (8Mx32) and 64MB (16Mx32.)
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 5 for installation
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 manufacturers use these signals, so
they disable them.