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FO-4500H
HD813201F (IC14) Terminal descriptions
Code
Terminal No.
MAS
UDS
LDS
MDEN
MA/MD 0
MA/MD 1
MA/MD 2
MA/MD 3
MA/MD 4
MA/MD 5
MA/MD 6
MA/MD 7
MA/MD 8
MA/MD 9
MA/MD10
MA/MD11
MA/MD12
MA/MD13
MA/MD14
MA/MD15
MA16
MA17
MA18
MA19
MA20
MA21
MR
MW
IOR
IOW
DRQTI
DACKO
DMA
I/O
74
O
27
Three-state output
23
Three-state output
25
O
79
I/O,
Three-state output
77
3
78
5
2
6
4
8
7
12
9
14
13
15
16
71
Three-state output
11
30
31
50
51
26
Three-state output
28
Three-state output
35
Three-state output
36
Three-state output
39
I
38
O
32
O
Memory Address Strobe (Memory address strobe terminal). When MAS
becomes "high" level, it indicates that address is output to MA/MD0 thru
MA/MD15 and MA16 thru MA21.
Upper Data Strobe (high-order data strobe terminal). When UDS becomes "low"
level, it indicates that IDP201 uses the high-order byte of the image bus.
Upper Data Strobe (low-order data strobe terminal). When LDS becomes "low"
level, it indicates that IDP201 uses the low-order byte of the image bus.
Memory Data Bus Enable (Memory data bus enable terminal). When MDEN
output terminal becomes "low" level, it indicates that valid data are present in
MA/MD0 thru MA/MD15. This output terminal is used to control the output of the
bidirectional bus buffer on MA/MD0 thru MA/MD15.
Memory Address Data Bus 0 thru 15 (Memory address data bus). In this bus for
image bus operation, the address and data are multiplexed. MA/MD0 thru
MA/MD15 are used as follows.
(1) When MAEN is "low" and MAS is "high", it is used as the output address line.
(2) When both MAEN and MDEN are "low" in the reading cycle, it is used as the
input data line.
(3) When both MAEN and MDEN are "low" in the writing cycle, it is used as the
input data line.
Memory Address Bus 16 thru 21 (memory address bus). When MAEN is "low"
and MAS is "high", it is used as the output address line.
Memory Read (Memory read terminal). When MR is turned to "low" level,
IDP201 reads the data from the image memory.
Memory Write (memory write terminal). When MW is turned to "low" level,
IDP201 writes the data in the image memory.
I/O Read (I/O read terminal). When IOR is turned to "low" level, IDP201 reads
the data from I/O device on the image bus. However, it is limited at DMA transfer
during data transfer with the transfer command and the coding process.
I/O Write (I/O write terminal). When IOW is turned to "low" level, IDP201 writes
the data in I/O device on the image bus. However, it is limited at DMA transfer
during data transfer with the transfer command and the decoding process.
DMA Request Input (DMA request input terminal). When I/O device on the
image bus requests DMA for IDP201, DRQTI becomes "high" level.
DMA Acknowledge Output (DMA acknowledge output terminal). When this
output terminal is turned to "low" level, IDP201 informs to the peripheral devices
on the image bus that DMA operation is approved.
Direct Memory Access (Direct memory access terminal). When DMA output is
turned to "low", it indicates that DMA transfer is executed.
In the coding process, the data is transferred from the I/O device (scanner) to
the image memory.
In the decoding process, the data is transferred from the image memory to I/O
device (printer).
5 – 12
Function
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