Memory Circuits - ENCAD 60e Service Manual

Novajet PROe Series Service Manual
The gate array contains the hardware logic for dot firing, monitoring
changes in the Carrier Assembly position, controlling DMA through
the parallel port, and generating the PWM (Pulse Width Modulation)
waveforms for the servo controller.
The gate array is a Xilinx device. It is a static RAM-based field
programmable gate array. This means that the logic that it imple-
ments is determined by configuration information in internal RAM
storage. Each time power is turned on, this information must be
downloaded from the system ROM. This type of gate array allows for
the flexibility of upgrading the logic by simply downloading the new
system software.

Memory Circuits

Memory is used to retain large amounts of information. This infor-
mation is stored in the device memory in the form of binary bits.
Printer memory consists of Flash EEPROM, DRAM, and EEPROM.
Maximum installable memory is as follows:
Flash EEPROM
Flash EEPROM is Electrically Erasable, Programmable, Read Only
Memory used to store instructions and data constants which the
microprocessor can access and interpret, with no loss of information
when power is off.
The system firmware is stored in Flash EEPROM. The Flash
EEPROM allows the firmware to be upgraded by simply downloading
a file containing the new firmware. It can be erased and repro-
grammed 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 repro-
grammed.
32 Theory of Operation
DRAM = 132 MB
Flash EEPROM = 1 MB
Serial EEPROM = 1KB