UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 397

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

(3) There is a delay of up to one count clock between the operation that starts a timer 3 (CE3
(4) While an instruction that writes data to the compare register (CR30) is executed, match between CR30, to which the
(5) Match between timer register 3 (TM3) and compare register (CR30) is detected only when TM3 is incremented.
(6) Although the timer register can be read, if counting up the timer and reading the timer register conflict, the read value
of the timer/counter (see Figure 11-12).
For example, if a timer/counter is used as an interval timer, the first interval will be extended by up to one clock. The
second and subsequent intervals will be as specified.
data is to be written, and timer register 3 (TM3) is not detected.
Write data to CR30 when timer 3 is executing counting operation so that the contents of TM3 do not match the value
of CR30 before and after writing (e.g., immediately after an interrupt request has been generated because TM3 and
CR30 have matched).
Therefore, the interrupt request is not generated even if the same value as TM3 is written to CR30.
of the timer register may be illegal. Therefore, do not read the timer register if at all possible.
If it is necessary to read the timer register, read it two or more times in a row in software, and assume the value of
the timer register is correct only when all the read values match.
Count Clock
TM3
CE3
Figure 11-12 Operation When Count Starts
0
CHAPTER 11 TIMER 3
Software count start directive (CE3 1)
Timing at which count actually starts
0
1
2
3
1) and the actual start
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