GETCAPS With Defining Byte

The Target returns its particular capabilities based on the value of the defining byte. The length of data returned depends on the defining byte and its associated capabilities. Table 24-19 details the specifics associated with possible defining bytes.

Table 24-19. GETCAPS Defining Byte Values
Value	Encoding	Description	Data Bytes Returned
0x00	TGTCAPS	Describes standard (Target) capabilities and features. Equivalent to GETCAPS Format 1 (same CCC but without a defining byte).	Returns three bytes of data.
0x01 – 0x59	Reserved	Reserved	These defining bytes are unsupported and are NACKed.
0x5A	TESTPAT	Returns a fixed 32-bit test pattern (0xA55AA55A).	Four bytes
0x5B – 0x90	Reserved	Reserved	These defining bytes are unsupported and are NACKed.
0x91	CRCAPS	Describes capabilities and features related to a Controller-capable (that is, a Secondary Controller) device, and its behavior during the Controller handoff.	1-2 bytes. Refer to Table 24-20 below.
0x92	Reserved	Reserved	This defining byte is unsupported and is NACKed.
0x93	VTCAPS	Describes the capabilities and features related to a virtual Target-capable device.	1 byte. Refer to Table 24-21 below.
0x94 – 0xD6	Reserved	Reserved	These defining bytes are unsupported and it is NACKed.
0xD7	DBGCAP S	Supported as a Vendor Extension for Debug Capable Device.	1 – N Bytes (DBGCAP1–DBGCAPN)
0xD8 – 0xDF	Reserved	Reserved	These defining bytes are unsupported, and it is NACK'd.
0xE0 – 0xFE	Vendor Extension s	Target treats the GETCAPS CCC as a Directed Vendor CCC.	These defining bytes are supported only if “IC_SLV_VEND_CCC_EN” is set to 1.
FF	Reserved	Reserved	This defining byte is unsupported and is NACK'd.

The byte format for defining byte ‘91’ is documented in Table 24-20.

Table 24-20. CRCAPS Byte Format
Byte	Bit	Field	Field Value
BYTE 1	0	Hot-Join Support	0
	1	Group Management Support	1
	2	Multi-Lane Support	Returns 0, as it is not supported.
	7:3	Reserved	Returns 0, as this field is Reserved.
BYTE 2	0	In-Band Interrupt Support	1
	1	Controller Pass-Back	Returns 1, as this device automatically passes the Controller role back to the former Active Controller from which it received its Controller role.
	2	Deep Sleep Capable	The Reset value of this field is 1’b0, and the value is returned from the DEVICE_CTRL_EXTENDED[DEEP_SLEEP_CAP] register field, which can be programmed by the application.
	3	Delayed Controller Handoff	Returns 1. This feature is supported in Secondary Controller.
	7:4	Reserved	Returns 0, as this field is Reserved.

The byte format for defining byte ‘93’ is documented in Table 24-21.

Table 24-21. VTCAPS Byte Format
Byte	Bit	Field	Field Value
BYTE 1	2:0	Virtual Target Type	Returns 5; supports multiple virtual Target addresses.
	3	Group Management Support	Returns 0 as this field is Reserved.
	4	Side Effects	Returns 1. Configuration CCCs sent to this virtual Target’s dynamic address may impact other virtual Targets that are connected to or exposed by this device.
	5	Shared Peripheral Detect	Returns 1. Device uses shared Peripheral logic and supports the Virtual Target Detect operation.
	7:6	Reserved	Returns 0 as this field is Reserved.