95
CHAPTER 5 CLOCK GENERATOR
User’s Manual U15104EJ2V0UD
Table 5-2. Maximum Time Required for CPU Clock Switching
PCC2 PCC1 PCC0 PCC2 PCC1 PCC0 PCC2 PCC1 PCC0 PCC2 PCC1 PCC0 PCC2 PCC1 PCC0
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
0
0
0
16 instructions
16 instructions
16 instructions
16 instructions
0
0
1
8 instructions
8 instructions
8 instructions
8 instructions
0
1
0
4 instructions
4 instructions
4 instructions
4 instructions
0
1
1
2 instructions
2 instructions
2 instructions
2 instructions
1
0
0
1 instruction
1 instruction
1 instruction
1 instruction
Set Values After Switching
Set Values Before
Switching
Remark
One instruction is the minimum instruction execution time with the preswitched CPU clock.
PCC2 PCC1 PCC0
5.6 Changing System Clock and CPU Clock Settings
5.6.1 Time required for switching between system clock and CPU clock
The system clock and CPU clock can be switched using bits 0 to 2 (PCC0 to PCC2) of the processor clock control
register (PCC).
The actual switching operation is not performed directly after writing to PCC, but operation continues on the
preswitched clock for several instructions (refer to Table 5-2).
Содержание mPD178053
Страница 2: ...2 User s Manual U15104EJ2V0UD MEMO ...