Clocks and Power Manager

Table 3-23. Coprocessor 14 Clock and Power Management Summary

Function

Data in Rd

Instruction

 

 

 

Read CCLKCFG

MRC p14, 0, Rd, c6, c0, 0

 

 

 

Enter turbo mode

TURBO = 1

MCR p14, 0, Rd, c6, c0, 0

 

 

 

 

FCS = 1

 

Enter frequency change sequence

(Turbo mode bit may be set or

MCR p14, 0, Rd, c6, c0, 0

 

cleared in the same write)

 

 

 

 

Enter idle mode

M = 1

MCR p14, 0, Rd, c7, c0, 0

 

 

 

Enter sleep mode

M = 3

MCR p14, 0, Rd, c7, c0, 0

 

 

 

3.7.1Core Clock Configuration Register (CCLKCFG)

The CCLKCFG register (CP14 register 6), shown in Table 3-24, is used to enter the turbo mode and frequency change sequence. To enter the mode or sequence, software executes the appropriate function from Table 3-23. All core-initiated memory requests are completed before the Clocks and Power Manager initiates the desired mode or sequence.

To ensure that CCLKCFG[TURBO] does not change when entering the frequency change sequence, software must do a read-modify-write.

This is a read/write register. Ignore reads from reserved bits. Write zeros to reserved bits.

Table 3-24. CCLKCFG Bit Definitions

CP14

CCLKCFG

Clocks and Power Manager

Register 6

 

 

Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

reserved

FCS

 

 

 

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

 

 

Bits

 

 

Name

 

 

 

 

 

 

 

 

 

 

 

Description

 

 

 

 

 

 

 

 

 

 

 

[31:2]

 

 

 

 

reserved

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Frequency Change Sequence

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

 

FCS

 

0 – Do not enter frequency change sequence

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1 – Enter frequency change sequence

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Cleared on hardware, watchdog, and GPIO reset and when sleep mode exits.

 

 

Turbo Mode

0TURBO 0 – Do not enter turbo mode/Exit turbo mode 1 – Enter turbo mode

Cleared on hardware, watchdog, and GPIO reset and when sleep mode exits.

TURBO

0

Intel® PXA255 Processor Developer’s Manual

3-39

Page 101
Image 101
Intel PXA255 manual Core Clock Configuration Register Cclkcfg, Coprocessor 14 Clock and Power Management Summary