CHAPTER 6 CLOCK GENERATION FUNCTION
User’s Manual U13850EJ4V0UM
170
6.4.4 Software STOP mode
(1) Settings and operating states
This mode stops the entire system by stopping the main clock oscillator to stop supplying the internal main clock.
The sub clock oscillator continues operating and the on-chip sub clock supply is continued. When the FRC bit in
the processor clock control register (PCC) is set to 1, the sub clock oscillator’s on-chip feedback resistor is cut.
This sets ultra low power consumption mode in which the only current is the device’s leak current.
In this mode, program execution is stopped and the contents of all registers and internal RAM are retained as
they were just before software STOP mode was set.
This mode can be set only when the main clock is being used as the CPU clock. This mode is set when the STP
bit in the power saving control register (PSC) has been set to 1.
Do not set this mode when the sub clock has been selected as the CPU clock.
The operating statuses for software STOP mode are listed in Table 6-3.
(2) Cancellation of software STOP mode
Software STOP mode can be canceled by an non-maskable interrupt, an unmasked interrupt request, or a
RESET input.
When the STOP mode is canceled, an oscillation stabilization time is secured.
Table 6-3. Operating Statuses in Software STOP Mode (1/2)
STOP Mode Settings
Item
When Sub Clock Exists
When Sub Clock Does Not Exist
CPU
Stopped
ROM correction
Stopped
Clock generator
Oscillation for main clock is stopped and oscillation for sub clock continues
Clock supply to CPU and on-chip peripheral functions is stopped
16-bit timer (TM0)
Operates when INTWTNI is selected for count
clock (f
XT
is selected as count clock for watch
timer)
Stopped
16-bit timer (TM1)
Stopped
8-bit timer (TM2)
Stopped
8-bit timer (TM3)
Stopped
8-bit timer (TM4)
Operates when f
XT
is selected for count clock
Stopped
8-bit timer (TM5)
Operates when f
XT
is selected for count clock
Stopped (operation disabled)
8-bit timer (TM6)
Stopped
8-bit timer (TM7)
Stopped
Watch timer
Operates when f
XT
is selected for count clock
Stopped
Watchdog timer
Stopped
CSI0 to CSI3
Operates when an external clock is selected as the serial clock
I
2
C0
Note
,
I
2
C1
Note
Stopped
UART0,
UART1
Operates when an external clock is selected as the serial clock
Serial
interface
CSI4
Operates when an external clock is selected as the serial clock
IEBus (V850/SB2 only)
Stopped
A/D converter
Stopped
Note
Available only for the
µ
PD70303xAY and 70F303wAY.