Integra CROMA24 service manual Memory Circuits, Flash Eeprom

Croma24 Service Manual

The gate array contains the hardware logic for dot firing, monitor- ing changes in the Carrier Assembly position, controlling DMA for the serial 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 information 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:

DRAM = 2 MB

Flash EEPROM = 1 MB

Serial EEPROM = 1 KB

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. This set of instructions and data constants is called the “firmware” of the plotter.

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. It can be erased and reprogrammed more than 10,000 times.

THEORY OF OPERATION

Theory of Operation 31