Intel IXP400 manual Using the Product ID-Related Functions, Product ID Values, Bits Description

Intel® IXP400 Software

Access-Layer Components: Feature Control (IxFeatureCtrl) API

stepping. For the IXP42X product line, this register is used to determine the maximum core clock speed.

Note: CP15, Register 0 is read-only.

•EXP_UNIT_FUSE_RESET register in the Expansion Bus Controller - A software copy of this register, called the Feature Control Register, can be created and manipulated by this software component.

The Feature Control Register is a structure which contains information on which components are physically available on the processor. The detectable capabilities include the existence of key coprocessors or peripherals (PCI controller, AES coprocessor, NPEs, etc.). The ixFeatureCtrlHwCapabilityRead( ) function utilizes this register for detecting host processor capabilities.

Note: The only way to detect the core frequency on the IXP46X product line is to use the ixFeatureCtrlHwCapabilityRead( ) and check bits 22 and 23.

12.3.1Using the Product ID-Related Functions

The functions ixFeatureCtrlDeviceRead ( ) and ixFeatureCtrlProductIdRead( ) return values based upon the CP15 register discussed above. ixFeatureCtrlProductIdRead() returns the entire 32- bit value, as documented below. ixFeatureCtrlDeviceRead() only returns an indication of the processor product line; the IXP46X product line or IXP42X product line.

Table 36. Product ID Values

Bits	Description
31:28	Reserved. Value: 0x6
27:24	Reserved. Value: 0x9
23:20	Reserved. Value: 0x0
19:16	Reserved. Value: 0x5
15:12	Reserved. Value: 0x4
	Device ID.
11:9	IXP42X - 0x0
	IXP46X - 0x1
	Maximum Achievable Intel XScale® Core Frequency
	for the IXP42X product line only.
8:4	533 MHz — 0x1C
	400 MHz — 0x1D
	266 Mhz — 0x1F
	For the IXP46X product line, the value will be 0x00.
	Si Stepping ID.
3:0	A-step — 0x0
	B-step — 0x1

April 2005	IXP400 Software Version 2.0	Programmer’s Guide
184	Document Number: 252539, Revision: 007