Specifications

JP18 is the MODB select. By placing a jumper on JP18, this will enable you to change the reset

vector from 0xBFFE, 0xBFFF to 0xFFFE,0xFFFF. It is used in conjunction with the Download switch

(S1) on the Communications board. Pressing the Download switch pulls the MODA line low (open).

Function

1 MODB

2 VCC

CPU Hardware Mode select summary

JP18 Download Switch S1 (default is closed, pressing S1 opens)

MODB

MODA

closed closed Normal Expanded (reset at 0xFFFE,0xFFFF)

open open Special Bootstrap (for downloading programs into memory)

open closed Special Test (Default mode for Interactive C, reset at 0xBFFE, 0xBFFF)

JP19 is used to connect an external battery for SRAM battery backup. Use a 3-5 volt battery. This is

not needed if you use a Dallas battery backup memory module.

Function

1 +BT1 3-5Volt battery

2 ground

P1 is the Communications board DB9 RS232 connector. It is a simple three wire asynchronous serial

interface. When using Interactive C, set your PC serial port to 9600 baud, 1 start, 1 stop, 8 data, no

parity. Use a standard serial cable to connect the PC serial port to the Finger Board. If your PC has a

25 pin serial port, use a 9 to 25 pin adapter.

Function

1 n/c n/c not connected

2 TxD

3 RxD

4 n/c

5 ground

6 n/c

7 RTS

8 CTS