Texas Instruments TMS320C6747 DSP manual HC Root Hub B Register HCRHDESCRIPTORB, Registers, Field

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3.20 HC Root Hub B Register (HCRHDESCRIPTORB)

The HC root hub B register (HCRHDESCRIPTORB) defines several aspects of the USB host controller root hub functionality. HCRHDESCRIPTORB is shown in Figure 21 and described in Table 21.

Note: The device does not provide connections from the USB host controller to pins to provide external port power switching. Systems that implement port power switching must use other mechanisms to control port power.

Figure 21. HC Root Hub B Register (HCRHDESCRIPTORB)

31	20	19	18	17	16
PPCM[15-4]		PPCM[3]	PPCM[2]	PPCM[1]	PPCM[0]
R/W-0		R/W-0	R/W-0	R/W-0	R/W-0
15	4	3	2	1	0
DR[15-4]		DR[3]	DR[2]	DR[1]	DR[0]
R/W-0		R/W-0	R/W-0	R/W-0	R/W-0

LEGEND: R/W = Read/Write; -n= value after reset

Table 21. HC Root Hub B Register (HCRHDESCRIPTORB) Field Descriptions

Bit	Field	Value	Description
31-20	PPCM[15-4]	0	Port power control mask. PPCM[15] through PPCM[4] are reserved.
19	PPCM[3]		Port power control mask. PPCM[3] is the port power control mask for downstream port 3. Defines
			whether downstream port 3 has port power controlled by the global power control. System software can
			update these bits to simplify host controller driver and/or OTG driver coding.
		0	Global power control is implemented for downstream port 3.
		1	Per-port power control is implemented for downstream port 3.
18	PPCM[2]		Port power control mask. PPCM[2] is the port power control mask for downstream port 2. Defines
			whether downstream port 2 has port power controlled by the global power control. System software can
			update these bits to simplify host controller driver and/or OTG driver coding.
		0	Global power control is implemented for downstream port 2.
		1	Per-port power control is implemented for downstream port 2.
17	PPCM[1]		Port power control mask. PPCM[1] is the port power control mask for downstream port 1. Defines
			whether downstream port 1 has port power controlled by the global power control. System software can
			update these bits to simplify host controller driver and/or OTG driver coding.
		0	Global power control is implemented for downstream port 1.
		1	Per-port power control is implemented for downstream port 1.
16	PPCM[0]	0	Port power control mask. PPCM[0] is reserved.
15-4	DR[15-4]	0	Device removable. DR[15] through DR[4] are reserved.
3	DR[3]		Device removable. DR[3] is the device removable bit for downstream port 3. Defines whether
			downstream port 3 has a removable or nonremovable device.
		0	Downstream port 3 may have a removable device attached.
		1	Downstream port 3 has a nonremovable device attached.
2	DR[2]		Device removable. DR[2] is the device removable bit for downstream port 2. Defines whether
			downstream port 2 has a removable or nonremovable device.
		0	Downstream port 2 may have a removable device attached.
		1	Downstream port 2 has a nonremovable device attached.
1	DR[1]		Device removable. DR[1] is the device removable bit for downstream port 1. Defines whether
			downstream port 1 has a removable or nonremovable device.
		0	Downstream port 1 may have a removable device attached.
		1	Downstream port 1 has a nonremovable device attached.
0	DR[0]	0	Device removable. DR[0] is reserved.
28	Universal Serial Bus OHCI Host Controller			SPRUFM8–September 2008

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