C517A Datasheet, PDF (35/72 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

C517A
Compare Timer Operation
The compare timer receives its input clock from a programmable prescaler which provides input
frequencies, ranging from f_OSC/2 up to f_OSC/256. The compare timer is, once started, a free-running
16-bit timer, which on overflow is automatically reloaded by the contents of a 16-bit reload register.
The compare timer has - as any other timer in the C517A - their own interrupt request flags CTF.
These flags are set when the timer count rolls over from all ones to the reload value. Figure 13
shows the block diagram of compare timer and compare timer 1.
f _OSC /2
3-Bit Prescaler
Compare Timer
/2 /4 /8 /16 /32 /64 /128
Control (CTCON)
16
To Compare
Circuitry
16-Bit Compare Timer
16-Bit Reload (CTREL)
Figure 13
Compare Timer Block Diagram
CTF
Overflow
To Interrupt
Circuitry
MCB00783
Semiconductor Group
33