2–14

2.6.2

USBSTA: USB Status Register

All bits in this register are set by the hardware and will be cleared by MCU when writing a 1 to the proper bit location

(writing a 0 has no effect). In addition, each bit can generate an interrupt if its corresponding mask bit is set (R/C

notation indicates read and clear only by MCU).

7

6

5

4

3

210

RSTR

SUSR

RESR

PWOFF

PWON

SETUP

RSV

STPOW

R/C

R/C

R/C

R/C

R/C

R/C

R/O

R/C

BIT

NAME

RESET

FUNCTION

0

STPOW

0

SETUP overwrite bit. Set by hardware when setup packet is received while there is already a packet in the

setup buffer.

STPOW = 0

MCU can clear this bit by writing a 1. (Writing 0 has no effect)

STPOW = 1

SETUP overwrite

1

RSV

0

Reserved

2

SETUP

0

SETUP transaction received bit.

As long as SETUP is 1, IN and OUT on endpoint-0 is NAK regardless of the value of their real NAK bits.

SETUP = 0

MCU can clear this bit by writing a 1. (Writing 0 has no effect)

SETUP = 1

SETUP transaction received.

3

PWON

0

Power on request for Port-3.

This bit indicates if power-on to Port-3 has been received. This bit generates a PWON interrupt (If enabled).

PWON = 0

MCU can clear this bit by writing a 1. (Writing 0 has no effect)

PWON = 1

Power on to Port-3 has been received.

4

PWOFF

0

Power off request for Port-3. This bit indicates whether power-off to Port-3 has been received. This bit

generates a PWOFF interrupt (If enabled).

PWOFF = 0

MCU can clear this bit by writing a 1. (Writing 0 has no effect)

PWOFF = 1

Power off to Port-3 has been received

5

RESR

0

Function resume request bit

RESR = 0

MCU can clear this bit by writing a 1. (Writing 0 has no effect)

RESR = 1

Function resume is detected

6

SUSR

0

Function suspended request bit. This bit is set in response to a global or selective suspend condition.

SUSR =0 MCU can clear this bit by writing a 1. (Writing 0 has no effect)

SUSR =1 Function suspend is detected.

7

RSTR

0

Function reset request bit. This bit is set in response to host initiating a port reset. This bit is not affected by

USB function reset.

RSTR = 0 MCU can clear this bit by writing a 1. (Writing 0 has no effect)

RSTR = 1 Function reset is detected.