Datasheet

ST72321Rx ST72321ARx ST72321Jx
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16-BIT TIMER (Cont’d)
Notes:
1. After a processor write cycle to the OCiHR reg-
ister, the output compare function is inhibited
until the OCiLR register is also written.
2. If the OCiE bit is not set, the OCMPi pin is a
general I/O port and the OLVLi bit will not
appear when a match is found but an interrupt
could be generated if the OCIE bit is set.
3. In both internal and external clock modes,
OCFi and OCMPi are set while the counter
value equals the OCiR register value (see Fig-
ure 8 for an example with f
CPU
/2 and Figure 9
for an example with f
CPU
/4). This behavior is
the same in OPM or PWM mode.
4. The output compare functions can be used both
for generating external events on the OCMPi
pins even if the input capture mode is also
used.
5. The value in the 16-bit OC
iR register and the
OLVi bit should be changed after each suc-
cessful comparison in order to control an output
waveform or establish a new elapsed timeout.
Forced Compare Output capability
When the FOLVi bit is set by software, the OLVLi
bit is copied to the OCMPi pin. The OLVi bit has to
be toggled in order to toggle the OCMPi pin when
it is enabled (OCiE bit = 1). The OCFi bit is then
not set by hardware, and thus no interrupt request
is generated.
The FOLVLi bits have no effect in both One Pulse
mode and PWM mode.
Figure 48. Output Compare Block Diagram
OUTPUT COMPARE
16-bit
CIRCUIT
OC1R Register
16 BIT FREE RUNNING
COUNTER
OC1E CC0CC1
OC2E
OLVL1OLVL2OCIE
(Control Register 1) CR1
(Control Register 2) CR2
000OCF2OCF1
(Status Register) SR
16-bit
16-bit
OCMP1
OCMP2
Latch
1
Latch
2
OC2R Register
Pin
Pin
FOLV2 FOLV1