DM-COP8/20D National Semiconductor, DM-COP8/20D Datasheet - Page 229

• Manufacturer Part Number: DM-COP8/20D
• Description: CABLE FOR DEBUG MODULE 20-DIP
• Manufacturer: National Semiconductor

Specifications of DM-COP8/20D

• Accessory Type: 20-DIP Target Cable
• For Use With/related Products: MetaLink Debug Module
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: *DM-COP8/20D

Time Keeping
The time keeping routine is the most important software routine and is executed
irrespective of the other modules being executed. The program uses the IDLE timer T0
for this purpose. The IDLE Timer is a 16-bit timer and runs continuously at a fixed rate
of the instruction cycle clock. The IDLE Timer counter is not memory mapped and
consequently, the user can not read or write to it. The toggling of the twelfth bit of the
IDLE counter can be programmed to generate an interrupt. The interrupt is generated
every 4 ms at the maximum instruction cycle clock rate of 1 S. The software uses this
interrupt to update counters in Data Memory for time keeping. The time keeping routine
then sets a flag to update the display which is then used by the main program.
COP8SAx7 APPLICATION IDEAS
4-37