upd78f0134hgka1-9et-a Renesas Electronics Corporation., upd78f0134hgka1-9et-a Datasheet - Page 178

• Manufacturer Part Number: upd78f0134hgka1-9et-a
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

6.5 Cautions for 16-Bit Timer/Event Counters 00 and 01
(1) Timer start errors
(2) 16-bit timer capture/compare register 00n setting
(3) Capture register data retention timing
(4) Valid edge setting
(5) Re-triggering one-shot pulse
178
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 0n (TM0n) is started asynchronously to the count clock.
In the mode in which clear & start occurs on a match between TM0n and CR00n, set 16-bit timer
capture/compare register 00n (CR00n) to other than 0000H. This means a 1-pulse count operation cannot be
performed when 16-bit timer/event counter 0n is used as an external event counter.
The values of 16-bit timer capture/compare registers 00n and 01n (CR00n and CR01n) are not guaranteed after
16-bit timer/event counter 0n has been stopped.
Set the valid edge of the TI00n pin after setting bits 2 and 3 (TMC0n2 and TMC0n3) of 16-bit timer mode control
register 0n (TMC0n) to 0, 0, respectively, and then stopping timer operation. The valid edge is set using bits 4
and 5 (ES0n0 and ES0n1) of prescaler mode register 0n (PRM0n).
(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 OSPT0n bit to 1. Do not output the one-shot pulse again
until INTTM00n, which occurs upon a match with the CR00n register, or INTTM01n, which occurs upon a
match with the CR01n 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 0n with a software trigger, do not change
the level of the TI00n 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
TI00n pin or its alternate function port pin, resulting in the output of a pulse at an undesired timing.
Remark n = 0:
TM0n count value
n = 0, 1: PD78F0133H, 78F0134H, 78F0136H, 78F0138H, 78F0138HD
Count clock
Figure 6-40. Start Timing of 16-Bit Timer Counter 0n (TM0n)
CHAPTER 6 16-BIT TIMER/EVENT COUNTERS 00 AND 01
PD78F0132H
Timer start
0000H
User’s Manual U16899EJ3V0UD
0001H
0002H
0003H
0004H