UPD78F0890GK(A)-GAJ-AX NEC, UPD78F0890GK(A)-GAJ-AX Datasheet - Page 575

• Manufacturer Part Number: UPD78F0890GK(A)-GAJ-AX
• Description: 8BIT MCU, 128K FLASH, 7K RAM, LQFP
• Manufacturer: NEC

Specifications of UPD78F0890GK(A)-GAJ-AX

• Controller Family/series: UPD78F
• No. Of I/o's: 55
• Ram Memory Size: 7KB
• Cpu Speed: 20MHz
• No. Of Timers: 10
• No. Of Pwm: RoHS Compliant
• Core Size: 8bit
• Program Memory Size: 128KB
• Oscillator Type: External, Internal

21.4 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.
<Action>
software counter that uses a timer, and then initialize the ports.
• If supply voltage fluctuation is 50 ms or less in vicinity of POC detection voltage
Note 1
In a system where the supply voltage (V
After releasing the reset signal, wait for the supply voltage fluctuation period of each system by means of a
Notes 1.
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 21-3. 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 21 POWER-ON-CLEAR CIRCUIT
DD
User’s Manual U17554EJ4V0UD
) 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 or A/D converter
PRS
= Internal high-speed oscillation clock (8.4 MHz (MAX.)) (default)
where comparison value = 102:
PRS
(8.4 MHz (MAX.))/2
Note 2
12
,
50 ms
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