Cypress CY7C65113C manual Downstream Port Suspend and Resume, Hub Ports Data Register

CY7C65113C

.								ADDRESS 0x50
Hub Ports Data
Bit #	7	6	5	4	3		2	1	0
Bit Name	Reserved	Reserved	Reserved	Reserved	Port 4	Diff.	Port 3 Diff.	Port 2 Diff.	Port 1 Diff.
					Data		Data	Data	Data
Read/Write	R	R	R	R	R		R	R	R
Reset	0	0	0	0	0		0	0	0
			Figure 16-7.	Hub Ports Data Register

Bit [0..3] : Port x Diff Data (where x = 1..4).

Set to 1 if D+ > D- (forced differential 1, if signal is differential, i.e. not a SE0 or SE1). Set to 0 if D- > D+ (forced differential 0, if signal is differential, i.e. not a SE0 or SE1).

Bit [4..7] : Reserved. Set to 0.

16.4Downstream Port Suspend and Resume

The Hub Ports Suspend Register (Figure 16-8) and Hub Ports Resume Status Register (Figure 16-9) indicate the suspend and resume conditions on downstream ports. The suspend register must be set by firmware for any ports that are selectively suspended. Also, this register is only valid for ports that are selectively suspended.

If a port is marked as selectively suspended, normal USB traffic is not sent to that port. Resume traffic is also prevented from going to that port, unless the Resume comes from the selectively suspended port. If a resume condition is detected on the port, hardware reflects a Resume back to the port, sets the Resume bit in the Hub Ports Resume Register, and generates a hub interrupt.

If a disconnect occurs on a port marked as selectively suspended, the suspend bit is cleared.

The Device Remote Wakeup bit (bit 7) of the Hub Ports Suspend Register controls whether or not the resume signal is propagated by the hub after a connect or a disconnect event. If the Device Remote Wakeup bit is set, the hub will automatically propagate the resume signal after a connect or a disconnect event. If the Device Remote Wakeup bit is cleared, the hub will not propagate the resume signal. The setting of the Device Remote Wakeup flag has no impact on the propagation of the resume signal after a downstream remote wakeup event. The hub will automatically propagate the resume signal after a remote wakeup event, regardless of the state of the Device Remote wakeup bit. The state of this bit has no impact on the generation of the hub interrupt.

A resume bit is set automatically when hardware detects a resume condition on a selectively suspended downstream port. The resume condition is a differential ‘1’ for a low-speed device and a differential ‘0’ for a full-speed device.

These registers are cleared on reset or USB bus reset.

Hub Ports Suspend								Address 0x4D
Bit #	7	6	5	4	3	2	1		0
Bit Name	Device	Reserved	Reserved	Reserved	Port 4	Port 3	Port 2		Port 1
	Remote				Selective	Selective	Selective		Selective
	Wakeup				Suspend	Suspend	Suspend		Suspend
Read/Write	R/W	R/W	R/W	R/W	R/W	R/W	R/W		R/W
Reset	0	0	0	0	0	0	0		0
			Figure 16-8. Hub Ports Suspend Register

Bit [0..3] : Port x Selective Suspend (where x = 1..4).

Set to 1 if Port x is Selectively Suspended; Set to 0 if Port x Do not suspend. Bit 7 : Device Remote Wakeup.

When set to 1, Enable hardware upstream resume signaling for connect/disconnect events during global resume. When set to 0, Disable hardware upstream resume signaling for connect/disconnect events during global resume.

Document #: 38-08002 Rev. *D Page 32 of 49

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