6 CLOCK MANAGEMENT UNIT (CMU)
S1C33L26 TECHNICAL MANUAL
Seiko Epson Corporation
6-25
10.9 W Value Settings
Table 6.
PLLV[1:0]
W
0x3
8
0x2
4
0x1
2
0x0
Setting prohibited
(Default: 0x1)
D1
Reserved
D0
PLLPOWR: PLL Enable Bit
Turns the PLL on or off.
1 (R/W): On
0 (R/W): Off (Default)
Up to 200 µs is required before the PLL output clock stabilizes after PLLPOWR is set to 1. Specify this
wait time in the program before changing the system clock source to the PLL.
When not using the PLL, turn the PLL off (power-down mode) to reduce current consumption.
PLL Control Register 1 (CMU_PLLCTL1)
Register name Address
Bit
Name
Function
Setting
Init. R/W
Remarks
PLL Control
Register 1
(CMU_
PLLCTL1)
0x300109
(8 bits)
D7–4 PLLVC[3:0] PLL VCO Kv setup
PLLVC[3:0]
f
VCO
[MHz]
0x1 R/W Write-protected
0x8
0x7
0x6
0x5
0x4
0x3
0x2
0x1
Other
360 < f
VCO
≤
400
320 < f
VCO
≤
360
280 < f
VCO
≤
320
240 < f
VCO
≤
280
200 < f
VCO
≤
240
160 < f
VCO
≤
200
120 < f
VCO
≤
160
100
≤
f
VCO
≤
120
Not allowed
D3–0 PLLRS[3:0] PLL LPF resistance setup
PLLRS[3:0]
f
REFCK
[MHz]
0x8 R/W
0xa
0x8
Other
5
≤
f
REFCK
< 20
20
≤
f
REFCK
≤
150
Not allowed
Note: Make sure that the PLL is turned off (PLLPOWR/CMU_PLLCTL0 register = 0) before altering this
register.
D[7:4]
PLLVC[3:0]: PLL VCO Kv Setup Bits
Sets the VCO Kv circuit constant (VC value) according to the range of f
VCO
frequencies obtained by
<Output clock frequency
×
W>.
10.10 VC Value Settings
Table 6.
PLLVC[3:0]
f
VCO
[MHz]
0x8
360 < f
VCO
≤
400
0x7
320 < f
VCO
≤
360
0x6
280 < f
VCO
≤
320
0x5
240 < f
VCO
≤
280
0x4
200 < f
VCO
≤
240
0x3
160 < f
VCO
≤
200
0x2
120 < f
VCO
≤
160
0x1
100
≤
f
VCO
≤
120
Other
Setting prohibited
(Default: 0x1)
D[3:0]
PLLRS[3:0]: PLL LPF Resistance Setup Bits
Sets the LPF resistance value of the PLL (RS value) according to the input clock (OSC3) frequency.
10.11 RS Value Settings
Table 6.
PLLRS[3:0]
f
REFCK
[MHz]
0xa
5
≤
f
REFCK
< 20
0x8
20
≤
f
REFCK
≤
150
Other
Setting prohibited
(Default: 0x8)