UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 652

• Manufacturer Part Number: UPD784026
• Description: 16/8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

612
Cautions 1. If the STOP mode is used when using external clock input, the EXTC bit of the oscillation
STBC
2. Execute a NOP instruction three times after the standby instruction (after the standby mode has
7
0
stabilization time specification register (OSTS) must be set (1) before setting STOP mode. If the
STOP mode is used with the EXTC bit cleared (0) when using external clock input, the PD784026
may suffer damage or reduced reliability.
When setting the EXTC bit of OSTS to 1, be sure to input a clock in phase reverse to that of the
clock input to the X1 pin, to the X2 pin (refer to 4.3.1 Clock Oscillator).
been released). Otherwise, the standby instruction is not executed if execution of the standby
instruction conflicts with an interrupt request, and the interrupt is acknowledged after several
instructions that follow the standby instruction have been executed. The instruction that is
executed before the interrupt is acknowledged is the instruction that is started to be executed
within 6 clocks after the standby instruction has been executed.
Example
6
0
CK1
5
MOV STBC, #byte
NOP
NOP
NOP
Figure 22-3 Standby Control Register (STBC) Format
CK0
4
CHAPTER 22 STANDBY FUNCTION
3
2
0
STP
1
HLT
0
Address
0FFC0H
STP
CK1
0
0
1
1
0
0
1
1
HLT
CK0
0
1
0
1
0
1
0
1
On Reset
30H
Operating Mode
Internal System Clock Selection
f
f
f
f
Normal operating mode
HALT mode
STOP mode
IDLE mode
XX
XX
XX
XX
/2 (12.5 MHz)
/4 (6.25 MHz)
/8 (3.125 MHz)
/16 (1.5625 MHz)
R/W
R/W
(f
XX
=25 MHz)