Centronics 306 Technical Manual page 212

APPENDIX B
PARALLEL INTERFACE SPECIFICATION
FOR CENTRONICS PRINTERS
B.1 INTERFACE TIMING
In general, the data transfer sequence consists of the input device
placing the appropriate code on the data lines to the printer and then
generating a data strobe pulse. The printer, after a slight delay, responds
with an acknowledge pulse, of if the received data causes a busy condition,
the printer first activates the busy line for the duration of the busy
condition and then responds with an acknowledge pulse.
As a standard feature in all printers except the 101, data strobe
is not recognized until the last character has been acknowledged (gated
data strobe). As an option, however, data strobe can be recognized at any
time.
Normal Data Input - No Busy
The diagram in Figure B-1 shows the timing involved in transferring
data which does not cause a busy condition.
PARALLEL DATA
.h.ollsL
-11.0",SI
DATA STROBE
I(MIN} " , (MIN)
r
I
Pl-------------------------------------------
ACKNOWLEDGE
101/l01A/101S
ACK DELAY
7
usee
ACK 4
usee
I
l-1.0
",S (MIN)
I
I
500", S
(MAX)
I
I
r
r---ACKNOWLEDGE DELAY--_o i-ACK-I
101AL
102A 102AL 301 306
2.5-10 usee 7 usee 2.5-10 usee 2.5-10 usee
2.5-10 usee
2.5-5.0 usee
4
usee 2.5-5.0 usee
2.5-5,1)
usee 2.5-5.0 usee
Figure B-1. NORMAL DATA INPUT
B-1
500 501
2.5-10 usee 2.5-10 usee
2.5-5.0 usee 2.5-5.0 usee
Rev. E