Midas RTE-V821-PC, Руководство пользователя

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RTE-V821-PC USER’ S MANUAL
19
7. JEXT BUS SPECIFICATION
The JEXT connector is used to expand memory and I/O units. The local bus on this board is
connected to this connector.
The following tables list the pin arrangement of the JEXT connector and the functions of each
signal. The timing relationships between the signals are also shown below.
Number
Signal name
Number
Signal name
Number
Signal name
Number
Signal name
1 +5V 2 +5V 31 GND 32 GND
3 D0 4 D1 33 A8 34 A9
5 D2 6 D3 35 A10 36 A11
7 D4 8 D5 37 A12 38 A13
9 D6 10 D7 39 A14 40 A15
11 GND 12 GND 41 +5V 42 +5V
13 D8 14 D9 43 A16 44 A17
15 D10 16 D11 45 A18 46 A19
17 D12 18 D13 47 BHE- 48 GND
19 D14 20 D15 49 GND 50 RD-
21 +5V 22 +5V 51 WR- 52 RESET-
23 A0 24 A1 53 GND 54 GND
25 A2 26 A3 55 READY 56 INT-
27 A4 28 A5 57 GND 58 GND
29 A6 30 A7 59 CPUCLK 60 GND
JEXT Connector Pin Arrangement
Signal name Input/
output
Function
A[0..19] Output Address bus signal, which is originally the CPU address signal
received at a buffer.
BHE- Output Byte high enable signal, which is originally the CPU UBE-signal
received at a buffer
D[0..15] Input/
output
Data bus signal, which is originally the CPU data bus signal received
at a buffer.
It is pulled up with a 10 k
Ω
resistor on the board.
RD- Output Read cycle timing signal, which becomes active only when the JEXT
space is accessed.
WR- Output Write cycle timing signal, which becomes active only when the JEXT
space is accessed.
READY Input Signal indicating the end of a cycle to the CPU. It is valid only for
the JEXT space.
To have the CPU recognize READY securely, it is necessary to keep
READY active until RD- or WR- becomes inactive. It is pulled up
with a 10 k
Ω
resistor on the board.
INT- Input Active-low interrupt request signal, which is connected to the
INTP11- pin of the CPU via a buffer. It is pulled up with a 10 k
Ω
resistor on the board.
RESET- Output Active-low system reset signal
CLK Output Clock signal. The CLKOUT pin of the V821 is connected via a
buffer.
JEXT Connector Signals