Diamond Systems Low-Power PC/104 CPU Board With ZFx86 Processor Watchdog/Failsafe Features - J6

4.5 Auxiliary Serial Port Connector – J15

1

2

3

4

5

6

RX COM1	Pin 2 on DB9 #1
TX COM1	Pin 3 on DB9 #1
Ground	Pin 5 on DB9 #1
RX COM2	Pin 2 on DB9 #2
TX COM2	Pin 3 on DB9 #2
Ground	Pin 5 on DB9 #2

This 6-pin header is provided for auxiliary access to serial ports 1 and 2 with signals RX, TX, and Ground for each port. This connector may be used in low-cost limited I/O configurations as an alternative to the 80-pin connector J3.

Do not use both J15 and the corresponding pins on J3 simultaneously.

Diamond Systems’ cable no. 698005 converts the 6 pins to two standard DB9M connectors with industry-standard pinout for RS-232 DTE.

4.6 Watchdog/Failsafe Features – J6

ZFIX	1	2
+3.3V	3	4
PRST-	5	6

Ground

WDI

WDO

J6 serves two main functions. It is used for watchdog timer access, and it is used to enable the ZFx86 failsafe feature (ZFIX mode) for reprogramming the BIOS or downloading files to the flash memory. J6 also contains a reset indicator signal PRST- that goes low for 200ms whenever a system reset occurs.

When the CPU is installed with a Panel Board, the failsafe feature is activated with a momentary switch on the panel board labeled ZFIX, and the watchdog timer feature is accessed with header J9 on the upper right edge of the panel board.

The watchdog timer circuit is described on page 18 of this manual. It may be programmed directly, as described in the ZFx86 training manual included with the Prometheus-LC documents, or with Diamond Systems’ Universal Driver software.

The failsafe feature is described on page 19 of this manual.

Prometheus-LC CPU User Manual V1.0 Page 11