Canon LBP-1210 Service Manual page 111

D. Interface Controller PCB
1. Outline
The interface controller receives print information from an external device such as a host com-
puter through an interface cable.
Print information is divided into two types: CAPT commands used for the printer status and
information on the printer, and dot data that is converted from the resource-typed print data by
the host computer.
The dot data is sent to the engine controller circuit, and the engine controller controls the
laser diode emission.
The location of the ICs on the interface controller PCB are shown in Figure 2-3-3, and the
block diagram is shown in Figure 2-3-4.
2. Function of Blocks
a. ASIC (IC1)
1) Controls the input/output of the interface controller that comes with a DRAM.
2) Controls the timing of sending the dot pattern data to the engine controller.
3) Performs smoothing, halftone and so on.
b. CPU (IC2)
1) Controls the video interface, parallel interface (Centronics specification), and USB interface.
2) Processes the serial commands from the video interface.
3) Sends and receives the CAPT commands using the parallel interface and USB interface.
c. DRAM (IC3)
DRAM contains a memory capacity of 2 MB and stores the following information:
1) Dot data converted from image data. (Receive buffer).
d. EEPROM (IC5)
Stores the serial number of the USB interface.
CHAPTER 2
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