NEC uPD78056Y - Manual (Page 172)

172
CHAPTER 7 CLOCK GENERATOR
Table 7-3. Maximum Time Required for CPU Clock Switchover
Ч Ч Ч Ч
1 0 0 0 1 1 0 0 1 0 0 0 1 0 0 0
CSS
0 0 0 0
×
PCC0 PCC1 PCC2
1
×
1
PCC0 CSS PCC2 PCC1
0
0 0
0 1 1
0 0
0
1
0 0 0
0
1
Ч
1
Ч Ч
1 8 instructions
2 instructions
4 instructions 4 instructions
16 instructions
2 instructions
8 instructions
4 instructions 4 instructions
2 instructions
16 instructions 16 instructions 16 instructions
8 instructions 8 instructions
2 instructions
f X /2f XT instruction
(77 instructions)
f
X
/4f
XT
instruction
(39 instructions)
f X /8f XT instruction
(20 instructions)
f
X
/32f
XT
instruction
(5 instructions)
f
X
/16f
XT
instruction
(10 instructions)
f
X
/4f
XT
instruction
(39 instructions)
f
X
/8f
XT
instruction
(20 instructions)
f X /32f XT instruction
(5 instructions)
f X /16f XT instruction
(10 instructions)
f X /64f XT instruction
(3 instructions)
MSC = 1 MSC = 0
Set Values After Switchover Set Values before
Switchover
CSS CSS CSS CSS CSS
1 instruction 1 instruction
1 instruction
1 instruction
1 instruction 1 instruction 1 instruction
CSS
1 instruction
1 instruction
Remarks 1. One instruction is the minimum instruction execution time with the pre-switchover CPU clock.
2. MCS: Oscillation mode selection register bit 0
3. Figures in parentheses apply to operation with f X = 5.0 MHz and f XT = 32.768 kHz.
Caution Selection of the CPU clock cycle scaling factor (PCC0 to PCC2) and switchover from the main system
clock to the subsystem clock (changing CSS from 0 to 1) should not be performed simultaneously.
Simultaneous setting is possible, however, for selection of the CPU clock cycle scaling factor (PCC0 to
PCC2) and switchover from the subsystem clock to the main system clock (changing CSS from 1 to 0).
PCC0 PCC1 PCC2 PCC1 PCC2 PCC0 PCC1 PCC2 PCC0 PCC1 PCC2 PCC0 PCC1 PCC2 PCC0 PCC1 PCC2 PCC0