The PIA uses the same clock as the microprocessor so that one PIA cycle occurs for each machine cycle. The PIA can be set for one of four different "intervals", where each interval is some multiple of the clock (and therefore machine cycles). A value from 1 to 255 is loaded into the PIA which will be decremented by one at each interval. The timer can now be read by the microprocessor to determine elapsed time for timing various software operations and keep them synchronised with the hardware (TIA chip).
Capabilities
| Name | Purpose | |
| $284 | INTIM | Timer output (read only) |
| $294 | TIM1T | set 1 clock interval (838 nanosecond/interval) |
| $295 | TIM8T | set 8 clock interval (6.7 microsecond/interval) |
| $296 | TIM64T | set 64 clock interval (53.6 microsecond/interval) |
| $297 | T1024T | set 1024 clock interval (858.2 microsecond/interval) |
Related
see PIA