UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 304

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

9.8 CAUTIONS
(1) While timer/counter 1 is operating (while the CE1 bit of the timer control register 1 (TMC1) is set), malfunctioning may
(2) If the contents of the compare register (CR1n: n = 0 or 1) match those of TM1 when an instruction that stops timer register
264
occur if the contents of the following registers are rewritten. This is because it is undefined which takes precedence in
a contention, the change in the hardware functions due to rewriting the register, or the change in the status because of
the function before rewriting.
Therefore, be sure to stop the counter operation for the sake of safety before rewriting the contents of the following registers.
1 (TM1) operation is executed, the counting operation of TM1 stops, but an interrupt request is generated.
In order not to generate the interrupt when stopping the operation of TM1, mask the interrupt in advance by using the
interrupt mask register before stopping TM1.
• Prescaler mode register 1 (PRM1)
• Capture/compare control register 1 (CRC1)
• CMD2 bit of timer control register 1 (TMC1)
Example
Program that may generate interrupt request
CLR1
OR
CE1
MK0L, #C0H
Interrupt request
from timer/counter 1
occurs between
these instructions
CHAPTER 9 TIMER/COUNTER 1
OR
CLR1
CLR1
CLR1
Program that does not generate interrupt request
MK0L, #C0H
CE1
CIF10
CIF11
Disables interrupt
Clears interrupt request
from timer/counter 1
flag from timer/counter 1