CHAPTER 6 16-BIT TIMER/EVENT COUNTER 00
Preliminary User’s Manual U16846EJ1V0UD
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6.5 Cautions for 16-Bit Timer/Event Counter 00
(1) Timer start errors
An error of up to one clock may occur in the time required for a match signal to be generated after timer start.
This is because 16-bit timer counter 00 (TM00) is started asynchronously to the count clock.
Figure 6-35. Start Timing of 16-Bit Timer Counter 00 (TM00)
TM00 count value
0000H
0001H
0002H
0004H
Count clock
Timer start
0003H
(2) 16-bit timer capture/compare register 000 setting
In the mode in which clear & start occurs on a match between TM00 and CR000, set 16-bit timer
capture/compare register 000 (CR000) to other than 0000H. This means a 1-pulse count operation cannot be
performed when 16-bit timer/event counter 00 is used as an external event counter.
(3) Capture
register
data retention timing
The values of 16-bit timer capture/compare registers 000 and 010 (CR000 and CR010) are not guaranteed after
16-bit timer/event counter 00 has been stopped.
(4) Valid edge setting
Set the valid edge of the TI000 pin after setting bits 2 and 3 (TMC002 and TMC003) of 16-bit timer mode control
register 00 (TMC00) to 0, 0, respectively, and then stopping timer operation. The valid edge is set using bits 4
and 5 (ES000 and ES001) of prescaler mode register 00 (PRM00).
(5) Re-triggering one-shot pulse
(a) One-shot pulse output by software
When a one-shot pulse is output, do not set the OSPT00 bit to 1. Do not output the one-shot pulse again
until INTTM000, which occurs upon a match with the CR000 register, or INTTM010, which occurs upon a
match with the CR010 register, occurs.
(b) One-shot pulse output with external trigger
If the external trigger occurs again while a one-shot pulse is output, it is ignored.
(c) One-shot pulse output function
When using the one-shot pulse output of 16-bit timer/event counter 00 with a software trigger, do not change
the level of the TI000 pin or its alternate function port pin.
Because the external trigger is valid even in this case, the timer is cleared and started even at the level of the
TI000 pin or its alternate function port pin, resulting in the output of a pulse at an undesired timing.