em78f644nso28s ELAN Microelectronics Corp, em78f644nso28s Datasheet - Page 30

• Manufacturer Part Number: em78f644nso28s
• Description: Flash Series 8-bit Microcontroller
• Manufacturer: ELAN Microelectronics Corp

EM78F648/644/642/641/548/544/542/541N
8-Bit Microcontroller
20 •
6.1.15 Bank 0 RE (Mode Select Register)
Bit 7:
Bit 6 (TIMERSC): TCC, TC1, TC2, TC3, Timer A, & Timer B clock source select
Bit 5 (CPUS):
Bit 4 (IDLE):
CPU Operation Mode
Bit 7
-
Note:
Sleep mode
*
CPU : stop
Fm : stop
Fs : stop
TIMERSC
only when WDT IRC is Fs.
If the watchdog function is enabled before going into sleep mode, Fs does not stop.
Hence, some circuits like timer/counter (of which clock source is Fs) must be disabled before
going into sleep mode, especially when the corresponding interrupt is enabled.
Bit 6
Not used, set to “0” all the time
0: Fs is used as Fc
1: Fm is used as Fc
CPU Oscillator Source Select.
0: Fs: Sub frequency for WDT internal RC time base
1: Fm: Main-oscillator clock
When CPUS=0, the CPU oscillator selects the Sub-oscillator and
the Main oscillator is stopped.
Idle Mode Enable Bit.
0: IDLE=”0” + SLEP instruction
1: IDLE=”1” + SLEP instruction
Wake-up
(*)
Figure 6-2 CPU Operation Mode Block Diagram
CPUS
Bit 5
Wake-up
+ SLEP
IDLE = 0
IDLE = 0
+ SLEP
CPUS = 1
Bit 4
IDLE
(This specification is subject to change without further notice)
Fm : oscillation
Fs : oscillation
CPU : using Fm
CPU : using Fs
Fs : oscillation
Fm : stop
Normal mode
Green mode
Bit 3
Product Specification (V1.0) 05.05.2010
-
CPUS = 0
Sleep mode
Idle mode
IDLE = 1
IDLE = 1
+ SLEP
Wake-up
Bit 2
+ SLEP
-
Wake-up
Bit 1
CPU : stop
Fs : oscillation
Fm : stop
-
Idle mode
RESET
Bit 0
-