C517A Datasheet, PDF (32/72 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

C517A
Cpmpare / Capture Unit (CCU)
The compare/capture unit is one of the C517A’s most powerful peripheral units for use in all kinds
of digital signal generation and event capturing like pulse generation, pulse width modulation, pulse
width measuring etc. The CCU consists of two 16-bit timer/counters with automatic reload feature
and an array of 13 compare or compare/capture registers. A set of six control registers is used for
flexible adapting of the CCU to a wide variety of user’s applications.
The block diagram in figure 11 shows the general configuration of the CCU. All CC1 to CC4
registers and the CRC register are exclusively assigned to timer 2. Each of the eight compare
registers CM0 through CM7 can either be assigned to timer 2 or to the faster compare timer, e.g. to
provide up to 8 PWM output channels. The assignment of the CMx registers - which can be done
individually for every single register - is combined with an automatic selection of one of the two
possible compare modes.
(CTREL)
16-bit Reload
Compare Timer
Max.Clock = f_OSC/2
Timer 2
Max.Clock = f_OSC/12
"Internal Bus"
(CM0)
8x
16-bit
Compare
(CM7)
Capt./Comp. 4 (CC4)
Capt./Comp. 3 (CC3)
Capt./Comp. 2 (CC2)
Capt./Comp.1 (CC1)
16-bit Rel.Capt. (CRC)
Comp.
Shadow
Latch
Figure 11
Timer 2 Block Diagram
Port P4-
Control I/O-
Logik Latch
P5-
CC4EN I/O-
Latch
Port P1-
Control I/O-
Logik Latch
MCB01577
Semiconductor Group
30