Hardware manual

EUROCOM-17-5xx 3 Programmers Reference

Hardware Manual 75

3.12 Status Display

The EUROCOM-17-5xx features a seven-segment display on the front

panel and displays hexadecimal values from 0 to F.

This status display is designed as read/write register and uses the least

significant nibble of the byte.

As an example, the following sequence moves a 'D' in the hex display:

move.b #$0D,$FEC30000

The left decimal point of the hex display is used as watchdog indicator.

The watchdog indicator is illuminated if the watchdog timer has generated

a reset pulse.

The right decimal point of the hex display is controlled by the PA0 output

of the system CIO. After reset the right decimal point is illuminated.

RMon switches the decimal point off before the user program in the user

EPROMs is called.

The upper four bits of the display are write-enable bits for the lower four

bits. Only those bits of the lower nibble are changed where the

corresponding bit in the upper nibble is clear.

The display is only enabled when PA6 of the system CIO is low.