UPD75518 NEC, UPD75518 Datasheet - Page 141

• Manufacturer Part Number: UPD75518
• Description: 4 BIT SINGLE-CHIP MICROCOMPUTER
• Manufacturer: NEC

clock generation is started following the release of the STOP mode, regardless of whether the STOP mode
is released by RESET signal input or the generation of an interrupt.
(See Table 6-2.)
6.3 OPERATION AFTER A STANDBY MODE IS RELEASED
(1) If a standby mode is released by a RESET input, normal reset operation is performed.
(2) If a standby mode is released by the occurrence of an interrupt request, the interrupt master enable flag
The wait times used when the STOP mode is released do not include a time (a in Fig. 6-2) required before
Note This time does not include the time from the release of the STOP mode to the start of oscillation.
When the STOP mode is released by the occurrence of an interrupt, a wait time is determined by BTM.
(IME) determines whether to perform a vectored interrupt when the CPU resumes instruction execution.
(a) When IME = 0
(b) When IME = 1
After the standby mode is released, execution of an instruction is restarted immediately after the
instruction which set the standby mode.
The interrupt request flag is held.
After the standby mode is released, two instructions are executed, then a vectored interrupt is caused.
However, when the standby mode is released by INTW or INT2 (input of a testable signal), no vectored
interrupt is caused and the same processing as (a) above is performed.
(When f
(When f
Other than above
Other than above
BTM3
BTM3
–
–
–
–
–
–
–
–
X
X
BTM2
BTM2
= 6.0 MHz)
= 4.19 MHz)
0
0
1
1
0
0
1
1
Wave-form
at the X1 pin
Table 6-2 Selection of a Wait Time with BTM
BTM1
BTM1
0
1
0
1
0
1
0
1
GND
Fig. 6-2 Start of Clock Generation
BTM0
BTM0
1
1
1
1
0
1
1
1
Wait time
Wait time
STOP mode release
Approx. 2
Approx. 2
Approx. 2
Approx. 2
Use prohibited
Approx. 2
Approx. 2
Approx. 2
Approx. 2
Use prohibited
Note
Note
20
17
15
13
a
20
17
15
13
/f
/f
/f
/f
/f
/f
/f
/f
. ( ) indicates the value for f
. ( ) indicates the value for f
X
X
X
X
X
X
X
X
(Approx. 250 ms)
(Approx. 31.3 ms)
(Approx. 7.82 ms)
(Approx. 1.95 ms)
(Approx. 175 ms)
(Approx. 21.8 ms)
(Approx. 5.46 ms)
(Approx. 1.37 ms)
X
X
= 4.19 MHz
= 6.0 MHz
PD75518(A)
141