mg84fl54 Megawin Technology, mg84fl54 Datasheet - Page 60

• Manufacturer Part Number: mg84fl54
• Description: Full-speed Usb Micro-controller
• Manufacturer: Megawin Technology

When terminating Power-down by an interrupt, Power-down is exited, the oscillator is restarted, and an internal
timer begins counting. The internal clock will not be allowed to propagate and the CPU will not resume
execution until after the timer has reached internal counter full. After the timeout period, the interrupt service
routine will begin. To prevent the interrupt from re-triggering, the interrupt service routine should disable the
interrupt before returning.
15.1.5. Reset Recovery from Power-Down Mode
Wakeup from Power-down through an external reset is similar to the interrupt. At the rising edge of RST, Power-
down is exited, the oscillator is restarted, and an internal timer begins counting. The internal clock will not be
allowed to propagate to the CPU until after the timer has reached internal counter full. The RST pin must be
held high for longer than the timeout period to ensure that the device is reset properly. The device will begin
executing once RST is brought low.
It should be noted that when idle is terminated by a hardware reset, the device normally resumes program
execution, from where it left off, up to two machine cycles before the internal reset algorithm takes control. On-
chip hardware inhibits access to internal RAM in this event, but access to the port pins is not inhibited. To
eliminate the possibility of an unexpected write to a port pin when Idle is terminated by reset, the instruction
following the one that invokes Idle should not be one that writes to a port pin.
15.2. Power Control Register
PCON (Address=87H, Power Control Register)
7
6
5
4
3
2
1
0
SMOD
SMOD0
-
POF
GF1
GF0
PD
IDL
PD: Power-Down control bit.
0: This bit could be cleared by CPU or any exited power-down event.
1: Setting this bit activates power down operation.
IDL: Idle mode control bit.
0: This bit could be cleared by CPU or any exited Idle mode event.
1: Setting this bit activates idle mode operation.
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MG84FL54B Data Sheet
MEGAWIN