Hitachi 902 - Interface

15 - 12
15.4.3 Interface
(1) System : Conforming with Centronics standards (8-bit parallel)
(2) Transmission speed : 1000 cps Character mode
2000 bps (bytes/second) Graphic mode
(3) Sync system : Externally fed strobe pulse
(4) Handshaking : ACK/BUSY signal
(5) Input/output level : TTL level
(6) Input/output conditions
• DATA 1 to 8, FEED, INIT
NOTE: Both Fanin and Fanout are set to "1", 74LS or equivalent is connected on the
host side and a pull-up resistor (4.7 kΩ) is provided in the final stage.
• STB
•
BUSY, ACK, PE, ERROR
Vcc
Vcc
Vcc
4.7 kΩ
4.7 kΩ
4.7 kΩ
1000 PF