4.9.4.4.9 CLPR – Clock Prescaler Register


Bit	7	6	5	4	3	2	1	0
	CLPCE		CLTPS[2:0]			CLKPS[2:0]
Access	R/W	R	R/W	R/W	R/W	R/W	R/W	R/W
Reset	0	0	0	0	0	0	0	0

Bit 7 – CLPCE Clock Prescaler Change Enable

The CLPCE bit must be written to logic ‘1’ to enable a change of the CLTPS[2:0] and CLKPS[2:0] bits. The CLPCE bit is only updated when the other bits in CLPR are simultaneously written to ‘0’. CLPCE is cleared by hardware four cycles after it is written, or when CLTPS[2:0] bits and CLKPS[2:0] bits are written. Rewriting the CLPCE bit within this time-out period neither extends the time-out period nor clears the CLPCE bit.

Bit 6 – Reserved Bit

This bit is reserved and read as ‘0’.

Bits 5:3 – CLTPS[2:0] Timer Clock Prescaler Select

These bits select the division factor for the timer clock (CLK_T) of the system clock prescaler. See System Clock Prescaler in the Clock Switching from Related Links.

Table 4-56. CLTPS – Timer Clock Prescaler Select
CLTPS[2:0]			Division Factor
`0`	`0`	`0`	disabled (reset value)
`0`	`0`	`1`	1
`0`	`1`	`0`	2
`0`	`1`	`1`	4
`1`	`0`	`0`	8
`1`	`0`	`1`	16
`1`	`1`	`0`	32
`1`	`1`	`1`	64

Bits 2:0 – CLKPS[2:0] System Clock Prescaler Select

These bits select the division factor for the system clock (CLK_SYS) output. See System Clock Prescaler in the Clock Switching from Related Links. For power-sensitive systems, the CLKPS reset value can be optionally set to 8 by the CKDIV8 fuse. See Fuse Low Byte from Related Links.

Table 4-57. CLKPS – System Clock Prescaler Select
CLKPS[2:0]			System Clock Division Factor
`0`	`0`	`0`	1 (reset value)
`0`	`0`	`1`	2
`0`	`1`	`0`	4
`0`	`1`	`1`	8
`1`	`0`	`0`	16
`1`	`0`	`1`	32
`1`	`1`	`0`	64
`1`	`1`	`1`	128

Name:	CLPR
Offset:	0x03B
Reset:	0x00