upd78f0114hgb-8es-a Renesas Electronics Corporation., upd78f0114hgb-8es-a Datasheet - Page 158

• Manufacturer Part Number: upd78f0114hgb-8es-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
(4) Valid edge setting
(5) Re-triggering one-shot pulse
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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
Do not set the OSPT00 bit to 1 while the one-shot pulse is being output. To output the one-shot pulse again,
wait until the current one-shot pulse output is completed.
Do not input the external trigger again while the one-shot pulse is being output.
To output the one-shot pulse again, wait until the current one-shot pulse output is completed.
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 U16961EJ4V0UD
0001H
0002H
0003H
0004H