UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 248

• Manufacturer Part Number: UPD784026
• Description: 16/8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

(3) Rewriting compare register (CR01)
208
Remark ALV0 = 1
If the current value of the CR01 is changed to a smaller value, and the CR01 value is made smaller than the timer register
0 (TM0) value, the PPG cycle at that time will be extended to the time equivalent to a full-count by TM0. If CR01 is rewritten
after the compare register (CR00) and TM0 match, the output level at this time will be the inactive level until TM0 overflows
and becomes 0, and will then return to normal PPG output.
If CR01 is rewritten before CR00 and TM0 match, the active level will be output until CR00 and TM0 match. If CR00 and
TM0 match before TM0 overflows and becomes 0, the inactive level is output at that point. When TM0 overflows and
becomes 0, the active level will be output, and normal PPG output will be restored. CR01 rewriting should be performed
by the interrupt due to a match between TM0 and CR01, etc.
TM0
Count Value
CR00
CR01
TO0
0H
n1
Figure 8-27 Example of Extended PPG Output Cycle
When value n2 which is smaller than the
TM0 value n5 is written to CR01 here,
the PPG cycle is extended.
n3
n1
CHAPTER 8 TIMER/COUNTER 0
n3
n1
n2
n5
n3
If CR00 and TM0 match, TO0 enters
the inactive level. Otherwise, it
remains at the active level.
Full Count Value
n1
n4
n2
n4
n2