MG84FL54BD MEGAWIN [Megawin Technology Co., Ltd], MG84FL54BD Datasheet - Page 82

• Manufacturer Part Number: MG84FL54BD
• Description: Full-Speed USB micro-controller
• Manufacturer: MEGAWIN [Megawin Technology Co., Ltd]

23. Power-On Reset
The CPU will not start to work until the VCC power rises up to the Power-On Reset (POR) voltage. It means the
POR state is activated whenever the VCC level is below the POR voltage.
The Power-On Flag, POF, is set to “1” by the activated POR signal. Two occasions make the POR signal
activated:
(1) during power up (i.e., cold start), or
(2) when VCC power drops below the POR voltage.
It helps users to check if the running of the CPU begins from cold reset (power up) or warm reset such as RST-
pin reset, software reset (ISPCR.5) or Watchdog Timer reset. The POF bit should be cleared by software.
PCON (Address=87H, Power Control Register)
7
6
5
4
3
2
1
0
SMOD
SMOD0
-
POF
GF1
GF0
PD
IDL
POF: Power-ON Flag.
POF is set to “1” by hardware during power up (i.e., cold start) or when VCC power drops below the POR
voltage. It can be set or reset under software control and is not affected by any warm reset such as RST-pin
reset, software reset (ISPCR.5) and WDT reset. Note that it should be cleared by software.
Note: If use Megawin proprietary ISP code,POF will be cleared by the ISP code in mcu power-on procedure.
And application program must always write “0” on this bit in this ISP condition. Megawin released MG84FL54B
samples have inserted the ISP code in default. If user won’t need the ISP code or will insert self ISP code,
writer tool can support the erase and re-program to configure user setting .
82
MG84FL54B Data Sheet
MEGAWIN