SH7721 datasheet(856/1524 Pages) RENESAS

856 / 1524 page

Section 24

USB Host Controller (USBH)

Rev. 3.00 Jan. 18, 2008 Page 794 of 1458

REJ09B0033-0300

Bit

Bit Name

Initial

Value

R/W

Description

(Read) Low Speed Device Attached

This bit indicates the speed of the device attached to this

port. When this bit is set, a low-seed device is attached to

this port. When this bit is cleared, a full-speed device is

attached to this port. This bit is valid only when the CCS

bit is set.

0: A full-speed device is set

1: A low-speed device is set

LSDA

R/W

(Write) Clear Port Power

Writing a 1 clears the PPS bit. Writing a 0 has no effect.

(Read) Port Power Status

This bit reflects the power state of the port regardless of

the power-switching mode to be executed.

However, because the initial value of the NPS bit of the

USBHRDA is 1, this bit is first fixed to 1. The NPS bit must

first be cleared before the power is switched, as shown

below.

When an over-current condition is detected, this bit is

cleared. Writing SetPortPower or SetGlovalPower sets this

bit. Writing ClearPortPower or ClearGlobalPower clears

this bit. The PSM bit in USBHRDA and the PPCM bit in

USBHRDB determine which power control switch can be

used. Only Set/ClearGlobalPower controls this bit in global

switching mode (PSM= 0). If the PPCM bit of that port is

set in power switching mode (PSM = 1), only the

Set/ClearPortPower command is enabled. If the mask is

not set, the Set/ClearGlovalPowerCommand is enabled.

When the port power is disabled, the CCS, PES, PSS, and

PRS are reset.

0: Port power is off

1: Port power is on

Note:

If power switching is not supported, this bit is

always read as 1.

PPS

R/W

(Write) Set Port Power

Writing a 1 sets the PPS bit. Writing a 0 has no effect.

7 to 5



All 0

Reserved

These bits are always read as 0. The write value should

always be 0.

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