HP 3562A, Service Manual

Page: 310 / 570

C I RC U I T D E SC R I PTIONS
MO D E L 3562A
6-92
KYS E l
KEYBOARD S E L E CT
Active Low
LE D1 L
LE D2L
OREG E N L
O RE G L
PAO to PA7
RPG1
RPG2
The keyboard com mand register uses KY$E L to interrupt the keyboard
processor when the keyboard has been addressed by the system
processor.
LED 1 E NABLE
Active Low
This signal clocks the system data bus through the L E D's I nput
K
egister
into the keyboard L E D's Latch 1 .
LED 2 E NABLE
Active Low
This signal clocks the system data bus through the LE D's I nput Register
into the keyboard L ED's Latch 2.
OUTPUT REG IST E R E NABLE
Active Low
When this signal is low, keyboard data from the data output register
is put on the system bus.
OUT PUT REG I ST E R
Active Low
This signal clocks keyboard data into the data output register.
PORT AO to PORT A7
Port A l i nes are output l ines of the keyboard processor. The keyboard
processor uses PAO to PA6 to set up the key matrix and uses PA7 to
clock I RQT2 L to the A2 System CPU.
ROTAT ION PULSE G E N E RATOR 1
When the marker RPG is moved, T u rn Latch 1 sends RPG1 to the
keyboard processor.
ROTAT I O N PULSE G E N E RATOR 2
. . .. RP.G js Tu�n 2 .RP.(:;4
_
" .'
'. ,
.
XL
X C U RSOR
Active Low
YL
Output signal of L E D's Latch 1 . It enables the X c u rsor LED and Turn
Latch 1 .
Y C U RSOR
Active Low
Output signal of L E Ds Latch 1 . It enab les the Y c u rsor LED and T u rn
Latch 1 .