ENCAD T-200, Service Manual

Page: 31 / 162

Theory of Operation 2-8
ENCAD T-200 and T-200+ Service Manual
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 printing 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 proce-
dures.
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 one 168-pin 64-bit DIMM socket for a DRAM
memory module. The printer is supplied with a 32 Megabyte DIMM
installed on the MPWA. The following DIMM sizes are supported:
32MB, 64MB and 128MB.
Serial EEPROM
Serial EEPROM is an Electrically Erasable, Programmable, Read Only
Memory which provides storage for calibration constants and user
configuration data entered from the host computer.
An 8K bit serial nonvolatile EEPROM stores calibration and configura-
tion information. It retains data while the unit is off.