upd78f0730 Renesas Electronics Corporation., upd78f0730 Datasheet - Page 433

• Manufacturer Part Number: upd78f0730
• Description: 8-bit Single-chip Microcontroller
• Manufacturer: Renesas Electronics Corporation.

16.4 Cautions for Power-on-Clear Circuit
voltage (V
release of reset to the start of the operation of the microcontroller can be arbitrarily set by taking the following action.
Note 1
In a system where the supply voltage (V
<Action>
• If supply voltage fluctuation is 50 ms or less in vicinity of POC detection voltage
Notes 1.
After releasing the reset signal, wait for the supply voltage fluctuation period of each system by means of a
software counter that uses a timer, and then initialize the ports.
POC
2.
), the system may be repeatedly reset and released from the reset status. In this case, the time from
If reset is generated again during this period, initialization processing <2> is not started.
A flowchart is shown on the next page.
No
Figure 16-3. Example of Software Processing After Reset Release (1/2)
Setting 8-bit timer H1
(to measure 50 ms)
50 ms has passed?
processing <1>
processing <2>
(TMIFH1 = 1?)
Clearing WDT
Initialization
Initialization
Reset
Yes
Power-on-clear
CHAPTER 16 POWER-ON-CLEAR CIRCUIT
Preliminary User’s Manual U19014EJ1V0UD
DD
) fluctuates for a certain period in the vicinity of the POC detection
;
; f
; Setting of division ratio of system clock,
Check the reset source
Initialize the port.
Source: f
Timer starts (TMHE1 = 1).
such as setting of timer
RL
= Internal low-speed oscillation clock (264 kHz (MAX.)) (default)
where comparison value = 104: ≅ 50 ms
RL
(264 kHz (MAX.))/2
Note 2
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