8 Nov
2005
8 Nov
'05
11:32 p.m.
OK, here's a pinout from the schematic.
Rear of machine, looking down into the edge connector
on the 98770-66534 board
MonAck/ --( )-- WrFull/
MonStb --( )-- DD15
Gnd --( )-- MonClrAddr/
Gnd --( )-- +5V
MD(6) --( )-- +5V
MD(7) --( )-- +5V
MD(4) --( ) N/C
MD(5) --( )-- -Vm
MD(2) --( )-- -Vm
MD(3) --( )-- +Vm
MD(0) --( )-- +Vm
MD(1) --( )-- Gnd
MD(9) --( )-- Gnd
MD(8) --( )-- MD(12)
MD(11) --( )-- MD(13)
MD(10) --( )-- MD(14)
DA14 --( )-- Gnd
Gnd --( )-- Init/
Where :
+Vm = +18V monitor supply from mainframe PSU
-Vm = -18V monitor supply from mainframe PSU
DA14, DD15 are 2 blanking/control signals (derrived, sortof, from address
14 and data 15), mainframe to monitor
Init/ = mainframe reset signal (to monitor)
MocAck/ = Vertical timing signal from monitor text PCB
MonStb = Charater strobe from monitor text PCB
WrFull/ = Buffer full (to monitor text PCB)
MonClrAddr/= Clear buffer memory address (end of line) from monitor text PCB
MD(n) = 15 bit date word to monitor text PCB
0...6 == Ascii code
7 = chracter set seelct (or alternatively, 0..7 = character code :-))
8 = cursor at this location
9 = inverse video
10 = blink
11 = underline
12..14 = colour select (not used on mono monitor)
Indeed pretty helpful. Matches to what I've found out.
Here it is with relation to the boardswapper guides:
NP/=MonAck/ --( )-- WrFull/=FLB/
NW/=MonStb --( )-- DD15=GS
Gnd --( )-- MonClrAddr/=NL/
Gnd --( )-- +5V
I6=MD(6) --( )-- +5V
CS=MD(7) --( )-- +5V
I4=MD(4) --( ) N/C
I5=MD(5) --( )-- -Vm
I2=MD(2) --( )-- -Vm
I3=MD(3) --( )-- +Vm
I0=MD(0) --( )-- +Vm
I1=MD(1) --( )-- Gnd
IV=MD(9) --( )-- Gnd
CUR=MD(8) --( )-- MD(12)=RDA
UL=MD(11) --( )-- MD(13)=GRA
B=MD(10) --( )-- MD(14)=BLA
AS=GS/=DA14 --( )-- Gnd
Gnd --( )-- Init/
where
NP = New Page (=> load start address + AS + GS from block 0 at address 600000 into
address register)
NL = New Line (=> read one line from crt buffer into line buffer)
NW = New Word (=> provide next character+attribute data to monitor)
AS = Alpha Select (=> enable alpha display, used as GS/ for switching between alpha and
graphics on the monochromes)
GS = Graphics Select (=> enable graphics display on the 9845C only, where alpha &
graphics can be displayed simultaneously)
FLB = Full Line Buffer
For the 9845C, the +5V triggers the power-on procedure for the 98770A monitor.
For the 98780A, maybe the DA14 line is used to switch between a blinking/nonblinking
cursor, identified as CURS signal. I assume that the MD12-14 lines are the ones that are
not connected in that 98780A.
Quite interesting the INIT/-signal is looped through to the monitor.
You really need the schematics :-)
Yes, Dave Colver told me the CD is almost finished.
-- Ansgar