Sage II - Hardware Changes on Sage II; PROM Changes; CPU Board Changes

SAGE
II
SERVICE
KIT
CPU BOARD
CIRCUIT
DESCRIPTIONS
LIST
0F
SIGNAL
ABBREVIATI0NS
(conr)
RDY+
Floppy
dtsk
conrroller
READY
lnpur
RD-
Read
actlve
1ow
(delayed
I
T
srare)
RMr-
software
reset
for
H.g/carrler
detect lnterrupt
RX2I+
Receive
lnterrupt
from
modem
port
RXII.+
ReceLve
lnterrupt
from
terminal port
RW-
1-Readr0=Write
RG-
Ring
detect
from
modem
port
nA/l+
Ras
outputs
to rams
RF-
Refresh granted
from
arbltration
active
row
RF+
Refresh granted
from
arbltratlon
active
htgh
SC+
Control
llne
for
IEEE
488 buffer
SRES+
Systern
reset
from
reset
SW or
CpU
S1-
Termlnal
port
chip
select
(U25)
52-
Modem porr
chlp
selecr
(U26)
SL0-
Drlve
select
0
(decoded)
SLl-
Drlve
select
I
(decoded)
SI+
Software lnterrupt
TM-
Tlrner
chlp selecr
(U9)
TXII+
Transmlt
lnterrupt
from
terminal
port
TX2I+
Transmlt
lnterrupt
from
modem
port
Tc+
Terrnlnal
count
lnput
to
floppy
dtsk
controller
UDS+
Upper
Data
Strobe acrlve
hlgh
UWO+
Upper
byte wrlte
nlbble
3
UI^II+
Upper
byte
wrlte
ntbble
4
WR-
Write
active
low
(delayed
2
T srares)
hICK+
llrite
clock for
floppy
dtsk
controller
WFf-
Wrlte
protect
input
from
dlsk
drive
64
Khz
Refresh
clock.
High
3.125 usec
every
ls.6zs
usec
7o