103
AT94KAL Series FPSLIC
Rev. 1138G–FPSLI–11/03
Figure 56.
Effects on Unsynchronized OCR1 Latching
Note:
1. X = A or B
Figure 57.
Effects of Unsynchronized OCR1 Latching in Overflow Mode
Note:
1. X = A or B
During the time between the write and the latch operation, a read from OCR1A or OCR1B will
read the contents of the temporary location. This means that the most recently written value
always will read out of OCR1A/B.
When the OCR1X contains $0000 or TOP, and the up/down PWM mode is selected, the out-
put OC1A/OC1B is updated to Low or High on the next compare match according to the
settings of COM1A1/COM1A0 or COM1B1/COM1B0. This is shown in Table 32. In overflow
PWM mode, the output OC1A/OC1B is held Low or High only when the Output Compare Reg-
ister contains TOP.
Counter Value
Compare Value
PWM OutputOC1X
(1)
Synchronized
OCR1X
(1)
Latch
Counter Value
Compare Value
PWM OutputOC1X
(1)
Unsynchronized
OCR1X
(1)
Latch
Glitch
Compare Value Changes
Compare Value Changes
PWM Output OC1x
(1)
PWM Output OC1x
(1)
Unsynchronized OC1x
(1)
Latch
Synchronized OC1x
(1)
Latch
Compare Value Changes
Compare Value Changes