1 Specification BAB-40/60
1.3.12 VIC Timer The VIC contains a timer which can be programmed to output a periodic wave form on LIRQ2. The available frequencies are 50 Hz, 100 Hz, and
1000 Hz. The VIC timer is typically used as a tick timer for multi-tasking operating systems.
1.3.13 Watchdog
Timer
The watchdog timer monitors the activity of the microprocessor. If the microprocessor does not access the watchdog timer within the time-out period of 130 ms to 17 min, a reset pulse is generated. After reset, the watchdog timer is disabled. The time-out period becomes effective after the first access to the watchdog configuration register.
After reset the software can read PA7 of the CIO to distinguish between a watchdog reset and a reset generated by other sources. This watchdog indicator is only cleared by power-up reset, the reset switch, a VMEbus
SYSRESET
, a VIC remote reset, or by a write access to the watchdog.
The time-out period is derived from a quartz oscillator so that tolerances can be neglected.
1.3.14 Status Display The BAB-40/60 features a four LED display on the front panel and displays values from 0 - F.
This status display ($FEC3.0000) is designed as a read / write register and uses the least significant nibble of the byte.
1.3.15 Reset Reset may be initiated by six sources:
•supply voltage drop below 4.75 V or power-up
•reset jumper J1401
•VMEbus
SYSRESET
•VIC remote control reset register
•Watchdog
•CPU RESET instruction
10 Hardware Manual
