Samsung SCX-4521F Series Service Manual page 166

2. Main Board Control Part
Main control part of SCX-4517F is made of ASIC(CPU, Image processor, PC I/F part
include,
Scan interface part, FAX Modem part and Printing process I/F part.
CPU handles the BUS control, I/O interface, scan interface, PC interface
and other miscellaneous driver circuit.
1) Main Board
Main Board has a function of sending Current Image Video Data to LSU of the
machine, controlling motor Driving Circuit and monitoring Paper Exit Sensor, Cover
Open switch, OPE Panel Inputs.
2) Main Controller
-CPU : Chorus2 is the main CPU and is made up on the 16/32bit RISC
-Summary of the Key Function Block:
▶ 1.8V for internal Core, 3.3V for I/O Pad with 4KByte Cache.
▶ Image Processor included.
▶ On-Chip clock generator with PLL.
▶ Memory and External Bank Control.
▶ DMA Control (5-Channel)
▶ Interrupt Control.
▶ 2-port USB Host/1-port USB device(ver 1.1) interface control.
▶ Parallel interface control.
▶ UART(2-Channel)
▶ Synchronous Serial Interface Control.
▶ A/D Converter(10-bit, 2channel).
▶ General I/O Port control.
▶ Tone Generator.
▶ RTC with calendar function.
▶ S/W Assistant function(Rotator)
-Flash Memory : Stores system program and can be updated to the newer system
program code through the PC interface.
It stores the FAX Journal List, One Touch dial number, speed dial number, and
machine configuration setup data.
architecture using ARM7TDMI core.
Main CPU controls the whole system according to the program code
which stored in the Flash-ROM memory.
.Capcity : 2 Mbyte
.Access Time : 70 nsec