Rev 1.00

March 22, 2010

9

HT45B0K

SPI to USB Bridge

is set to 0. When the MCU detects the suspend mode SUSP, the resume signal RESUME

which causes MCU to wake up should be remembered and taken into consideration.

Bit 2

URST: USB reset indication flag

0: No USB reset event occurred.

1: USB reset event has occurred.

The USB bit is set and cleared by USB SIE. When the URST bit is set to 1, it indicates

that a USB reset event has occurred and a USB interrupt will be initiated.

Bit 1

RMWK: USB remote wake-up command

0: disable USB remote wake-up command

1: initiate USB remote wake-up command

The RMWK is set to 1 by MCU to force the USB host leaving the suspend mode. Set

RMWK bit to 1 to initiate the remote walk-up command. When the RMWK bit is set to 1,

a 2μs delay for clearing this bit to 0 is necessary to ensure that the RMWK command is

accepted by the SIE.

Bit 0

SUSP: USB suspend indication flag

0: USB leaves the suspend mode.

1: USB enters the suspend mode.

This bit is read only and set to 1 by SIE to indicate that the USB bus enters the suspend

mode.

The USB interrupt is also generated when the SUSP bit is asserted.

USR Register

The USR (USB endpoint interrupt status register) register is consisted of the endpoint request

flags (EP0IF~EP5IF) used to indicate which endpoint is accessed. When an endpoint is accessed,

the related endpoint request flag will be set to 1 by SIE and a USB interrupt will be generated if

the control bits related to the USB interrupt are enabled and the stack in the host MCU is not full.

When the active endpoint request flag is serviced, the endpoint request flag has to be cleared to 0

by application program.

USR Register

Bit

76543210

Name

――

EP5IF

EP4IF

EP3IF

EP2IF

EP1IF

EP0IF

R/W

――

R/W

R/W

R/W

R/W

R/W

R/W

POR

――

000000

Bit 7~6

Unimplemented, read as “0”.

Bit 5~0

EP5IF~EP0IF: Endpoint Interrupt request flags

0: the corresponding Endpoint is not accessed.

1: the corresponding Endpoint has been accessed.