Partitioning Across Multiple Boards

When you finally get the Xilinx board, you will notice that the upper half of the board is taken up by the Xilinx part and the programming EPROM. There is a small area at the bottom of the board that you can use to place components, but there won't be enough space here to put all the switches and lights that you'll need for Triscuit. You will want to put all the switches, LEDs, LED drivers, and switch debouncers on one board, and the Xilinx part on another board connected through the edge connectors. To do this you will need to define which signals are being passed between the boards, and on which edge connectors those signals will be passed. The edge connectors are accessed from your wirewrap board by wiring to the pins of the solder-on sockets on the bottom of the wire-wrap board. Note that the edge connector tabs are numbered. So, the bus definition for Triscuit is as follows. Note that the Address[7:0] and Data-out[7:0] lines go from the Xilinx board to the switch/light board and end up on LEDs, and the Data-in[7:0] lines go from switches on the switch-light board to the Xilinx board. The RESET, CLK and GO signals go from the switch/light board to the Xilinx board, and the RBAR-W signal comes back the other way and ends up on an LED.

Wire Wrap Side Component Side

Pin Signal Name Pin Signal Name

1 unusable A

2 GND B GND

3 C Address 0

4 D Address 1

5 E Address 2

6 F Address 3

7 H Address 4

8 J Address 5

9 K Address 6

10 L Address 7

11 Data-out 0 M Data-in 0

12 Data-out 1 N Data-in 1

13 data-out 2 P Data-in 2

14 Data-out 3 Q Data-in 3

15 Data-out 4 R Data-in 4

16 Data-out 5 T Data-in 5

17 Data-out 6 U Data-in 6

18 Data-out 7 V Data-in 7

19 W RESET

20 X CLK

21 Y RBAR-W

22 Z GO 23 24 25 26

27 GND GND

28 unusable 5 Volt