CD1283 Datasheet, PDF (48/94 Pages) Intel Corporation – IEEE 1284-Compatible Parallel Interface

CD1283 — IEEE 1284-Compatible Parallel Interface
useful in slow systems that cannot guarantee that the CPU can check the register after it is
cleared or before it is loaded with the revision code.
This procedure is also used as part of a diagnostic test suite. The device completes internal
initialization within 500 µsec. A timer (software or hardware) detects when the operation is not
completed within that time and cues if the device is functional.
Figure 15. Flow Diagram of the CD1283 Master Initialization Sequence
CLEAR
GFRCR
RCR
N
=0
?
Y
ISSUE RESET
COMMAND
GFRCR
N
=0
?
Y
GFRCR
= 25*
?
Y
CONTINUE
INIT PROCESS
N
* REVISION CODE FOR
REVISION E DEVICE = 25
FUTURE REVISIONS, IF
NECESSARY, WILL INCREMENT
THIS BY ONE; FOR EXAMPLE,
REVISION F WOULD BE 26, ETC.
48
Datasheet