Releasing Stop Mode By Reset Input; Operation After Release Of Stop Mode - NEC switch User Manual

(b) Releasing by RESET input
When the STOP mode is released by the RESET signal, the reset operation is performed after the
oscillation stabilization time has elapsed.
RESET
signal
Operation
mode
Oscillation
Clock
Remarks 1. f
2. The parenthesized values apply to operation at 6.0 MHz.
Releasing Source
Maskable interrupt request
RESET input
×: don't care
(3) Cautions an executing STOP instruction
After the STOP instruction is executed in the SE0 state (USBDM = 0, USBDP = 0), the STOP mode cannot be
released by a USB reset/Resume detection interrupt (INTUSBRE).
Therefore, the following control should be performed.
<Control method>
Do not execute the STOP instruction in the SE0 state.
In addition, when executing the STOP instruction in the suspend mode, execute both the following two
software countermeasures.
• Do not clear the USB reset/Resume detection interrupt request flag (USBREIF) between when the
suspend state is detected and when the STOP instruction is executed.
• Clear the USB reset/Resume detection interrupt request flag (USBREIF) when the 8-bit timer that is used
as the 3 ms timer for suspend state detection is reset.
CHAPTER 12
Figure 12-5. Releasing STOP Mode by RESET Input
STOP
instruction
STOP mode
Oscillation
stops
: System clock oscillation frequency
X
Table 12-4. Operation After Release of STOP Mode
MKxx
0
0
1
—
User's Manual U12978EJ3V0UD
STANDBY FUNCTION
Wait
15
(2 /f : 5.46 ms)
X
Oscillation
stabilization
Reset
wait status
period
Oscillation
IE
0 Executes next address instruction
1 Executes interrupt servicing
×
Retains STOP mode
— Reset processing
Operation
mode
Operation
185