UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 664

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

22.4 STOP MODE
22.4.1 STOP Mode Setting and Operating States
STOP mode setting is therefore performed by means of the “MOV STBC, #byte” instruction,
been released). Otherwise, several instructions may be executed after the STOP mode has been released and before the
interrupt is acknowledged. This may change the sequential relation between interrupt processing and instruction execution,
and cause a problem.
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The STOP mode is selected by setting (1) the STP bit of the standby control register register (STBC).
The only writes that can be performed on the STBC register are 8-bit data writes by means of a dedicated instruction.
Write an NOP instruction three times after the instruction that has set the STOP mode (or after the STOP mode has
Caution If the STOP mode is set when the condition to release the HALT mode is satisfied (refer to 22.3.2 HALT
* A/D converter operation is stopped, but if the CS bit of the A/D converter mode register (ADM) is set (1), the current
consumption does not decrease. D/A converter operation is not stopped.
Mode Release), the STOP mode is not set, but the next instruction is executed or execution branches
to a vectored interrupt service program. To accurately set the STOP mode, clear the interrupt request
before setting the STOP mode.
Clock oscillator
Internal system clock
CPU
I/O lines
Peripheral functions
Internal RAM
Bus lines
RD, WR output
ASTB output
REFRQ output
HLDRQ input
HLDAK output
Table 22-4 Operating States in STOP Mode
AD0 to AD7
A8 to A19
CHAPTER 22 STANDBY FUNCTION
Oscillation stopped
Stopped
Operation stopped
Retain state prior to STOP mode setting
All operation stopped*
Retained
High-impedance
High-impedance
High-impedance
High-impedance
Retained
High-impedance
Low level