UPD78F0138 NEC, UPD78F0138 Datasheet - Page 134

• Manufacturer Part Number: UPD78F0138
• Description: (UPD78xxxx) 8-Bit Single-Chip Microcontrollers
• Manufacturer: NEC

134
Notes 1.
2.
3.
4.
CPU clock: f
f
f
XP
R
Before shifting from status 2 to status 3 after reset and STOP are released, check the X1 input clock
oscillation stabilization time status using the oscillation stabilization time counter status register
(OSTC).
When shifting from status 2 to status 1, make sure that MCS is 0.
The watchdog timer operates using Ring-OSC even in STOP mode if “Ring-OSC cannot be stopped”
is selected by a mask option. Ring-OSC division can be selected as the count source of 8-bit timer
H1 (TMH1), so clear the watchdog timer using the TMH1 interrupt request before watchdog timer
overflow. If this processing is not performed, an internal reset signal is generated at watchdog timer
overflow after STOP instruction execution.
All reset sources (RESET input, POC, LVI, clock monitor, and WDT)
: Oscillating
Status 3
: Oscillating
(3) When “Ring-OSC cannot be stopped” is selected by mask option
XP
instruction
Interrupt
STOP
MCM0 = 1
Figure 5-13. Status Transition Diagram (3/4)
MCM0 = 0
(when subsystem clock is not used)
Interrupt
HALT
instruction
CHAPTER 5 CLOCK GENERATOR
Note 1
User’s Manual U16228EJ2V0UD
instruction
Interrupt
STOP
f
CPU clock: f
f
XP
R
STOP
: Oscillating
: Oscillating
Status 2
HALT
Note 3
HALT
instruction
Interrupt
R
Interrupt
instruction
MSTOP = 1
MSTOP = 0
STOP
Reset release
HALT instruction
Interrupt
Note 2
f
XP
: Oscillation stopped
CPU clock: f
f
Reset
R
: Oscillating
Status 1
Note 4
R