upd78f0124hgba1-8et-a Renesas Electronics Corporation., upd78f0124hgba1-8et-a Datasheet - Page 157

• Manufacturer Part Number: upd78f0124hgba1-8et-a
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

6.5 Cautions for 16-Bit Timer/Event Counter 00
(1) Timer start errors
(2) 16-bit timer capture/compare register 000 setting
(3) Capture register data retention timing
(4) Valid edge setting
(5) Re-triggering one-shot pulse
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.
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.
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.
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).
(a) One-shot pulse output by software
(b) One-shot pulse output with external trigger
(c) One-shot pulse output function
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.
If the external trigger occurs again while a one-shot pulse is output, it is ignored.
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.
TM00 count value
Count clock
Figure 6-35. Start Timing of 16-Bit Timer Counter 00 (TM00)
CHAPTER 6 16-BIT TIMER/EVENT COUNTER 00
Timer start
0000H
User’s Manual U16962EJ3V0UD
0001H
0002H
0003H
0004H
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