Flash Memory; Sensor Input Circuit - Samsung SCX-4100 Service Manual

Summary of Product
4.3.1 ASIC (Chorus2)
The Chorus2 (16Bit RISC Processor) ASIC is the main processor controlling the whole system. It controls
all of the printing and scanning functions using a system program stored in flash memory.
•Main function block
• Completely Integrated System for Embedded Applications,
• 16/32 Bit Risc Architecture, Efficient and Powerful ARM7TDMI CPU
• LSU Interface Module for Interfacing PVC with LSU
• 5 Channel General Purpose DMA Controller for High Speed I/O
• Dual Memory Bus Architecture
• Operating frequency : 66MHz
• Operating power : 1.8V(internal), 3.3V(external)

4.3.2 Flash Memory

This stores the system program. Firmware upgrade is achieved by downloading from the new image using the PC
Interface.
• Capacity : 1M Byte
• Access Time : 70 nsec
4.3.3 SDRAM
This is used as a buffer, system working memory area, etc. while printing and scanning.
• Capacity :
SCX-4100
8 M byte
• Access Time : 15 nsec

4.3.4 Sensor input circuit

1) Paper Empty Sensing
The Paper Empty sensor (Photo Interrupter) on the SMPS/HVPS PBA is monitored by the CPU.
When the cassette is empty the printer displays a message on the LCD panel.
2) MP Sensing
Presence of paper in the MP tray is detected by operation of the MP Sensor (Photo Interrupter) on the
SMPS/HVPS PBA. The CPU monitors this signal to recognize paper in the MP, and paper is fed from MP if
there is paper present.
Service Manual
4-10
Samsung Electronics