Samsung SF-4500 Service Manual page 36

6-1-2-5. DRAM CONTROLLER
As KS32C6200 has DRAM controller in it, DRAM can
be connected with external memory.
The control mode of DRAM controller enabling
EARLY WRITE, NORMAL READ, PAGE MODE,
and BYTE/HALF WORD ACCESS supports EDO
DRAM as well as normal DRAM. DRAM
READ/WRITE signals are /RD and /WR signals
used to control system buses. It supports CAS
BEFORE RAS for DRAM REFRESH and self-refresh
mode for DRAM backup. Connected with common
/LCAS, /UCAS and RAS [1:0], it consists of 2 banks.
Though each may be connected with up to 1M - 4M
halfword, two (2) of 512 Kbytes are
connected for this product.
PPD(7 : 0)
BUSY
nSTROBE
nACK
Samsung Electronics
DATA
Fig.6-1-5 Compatibility Hardware handshaking Timing
6-1-2-6. PARALLEL PORT INTERFACE
This part connected with the computer through the
centronics connector makes possible parallel
interface with the computer. Data is transmitted
according to the standard of IEEE P1284. This MFP
controller supports compatibility mode the
traditional way to transmit print data, nibble mode
(4bit data) to upload data to the computer, and
duplex high-speed transmission with the computer
ECP (Extended Capabilities Port: 8bit data
transmission) all together.
It enables PC data to be printed and scanned data to
be uploaded quickly to the computer. Besides,
various data transmission and reception with the
computer such as uploading received fax data,
downloading fax data to be sent, and monitoring sys-
tem control signals and system conditions are carried
out here.
6-5