Vector Graphic Bitstreamer II, User Manual, Page: 45 / 54

Sockets U25 and U23 are large enou9h for 16-?in DIP's. None of the holes
are connected to anything on the board, so that all wiring must be done
using the adjacent j~nper areas C and D for U25 and E and F for U28.
There are five unused inverters on the board, in chip U21. The functions
of the pins are as follows:
In Out
1
2
3 4
5
6
9
8
11 10
Spare Inverters in U2l
Table 13
The last circuit, pins 10 and 11, should be reserved for inverting PINT
as explained in Section 2.7, unless G~is function is not needed.
There are two unused o?en collector NN~D gates, in chip U10. All the
pins for L~ese gates are accessible in jumper area 8. Each of these gates
can be used as an inverter, sim;?lyby tying the input to both of the input
pins. Note L~at ~~e output of the second gate is also available at pad L-l.
These gates are used in various ways for wiring u;? interrupts, as explained
in Section 2.7, but are otherwise available for the user.
Function Pad
Gate
1
in 8-1
Gate 1 in 8-2
Gate 1 out 8-3
Gate 2 in 8-4
Gate
2
in 8-5
Gate 2 out 8-6 and L-l
Spare Open Collector
NN-JD
Gates in Chip
UHJ
Table
14
There is a spare RS-232C line receiver and line driver circuit on the
board. The recei'-1er bput pin is U26-1, and the output pin is U26-3. The
driver input pin is U22-2 and the output pin is U22-3.