upd78f0134hgka1-9et-a Renesas Electronics Corporation., upd78f0134hgka1-9et-a Datasheet - Page 378

• Manufacturer Part Number: upd78f0134hgka1-9et-a
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

19.1 Standby Function and Configuration
19.1.1 Standby function
Notes 1.
Caution The RSTOP setting is valid only when “Can be stopped by software” is set for internal oscillator by
Remark MSTOP: Bit 7 of the main OSC control register (MOC)
available.
(1) HALT mode
378
Operation
Mode
Reset
STOP
HALT
The standby function is designed to reduce the operating current of the system. The following two modes are
HALT instruction execution sets the HALT mode. In the HALT mode, the CPU operation clock is stopped. If the
high-speed system clock oscillator, internal oscillator, or subsystem clock oscillator is operating before the HALT
mode is set, oscillation of each clock continues. In this mode, the operating current is not decreased as much as
in the STOP mode, but the HALT mode is effective for restarting operation immediately upon interrupt request
generation and carrying out intermittent operations.
2.
3.
4.
Status
the option byte.
MCC:
RSTOP: Bit 0 of the internal oscillation mode register (RCM)
MCM0:
When “Cannot be stopped” is selected for internal oscillator by the option byte.
When “Can be stopped by software” is selected for internal oscillator C by the option byte.
Operates using the CPU clock at STOP instruction execution.
Operates using the CPU clock at HALT instruction execution.
MSTOP = 0
Stopped
Oscillating
MCC = 0
Table 19-1. Relationship Between Operation Clocks in Each Operation Status
High-Speed System
Clock Oscillator
Bit 7 of the processor clock control register (PCC)
Bit 0 of the main clock mode register (MCM)
MSTOP = 1
Stopped
MCC = 1
CHAPTER 19 STANDBY FUNCTION
Stopped
Oscillating
Note 1
User’s Manual U16899EJ3V0UD
Internal Oscillator
RSTOP = 0 RSTOP = 1
Oscillating
Note 2
Stopped
Subsystem
Oscillating
Oscillator
Clock
Internal
oscillation
clock
Note 3
Note 4
CPU Clock
Release
After
Stopped
Stopped
Internal
oscillation
clock
Supplied to Peripherals
MCM0 = 0
Prescaler Clock
High-
speed
system
clock
MCM0 = 1