2–14

2.6.2

USBSTA: USB Status Register

All bits in this register are set by the hardware and are cleared by the 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 the 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 a setup packet is received while there is already a packet in the

setup buffer.

STPOW = 0

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

STPOW = 1

SETUP overwrite

1

RSV

0

Reserved = 0

2

SETUP

0

SETUP transaction received bit.

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

SETUP = 0

The MCU can clear this bit by writing a 1. (Writing a 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

The MCU can clear this bit by writing a 1. (Writing a 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

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

PWOFF = 1

Power off to port 3 has been received.

5

RESR

0

Function resume request bit

RESR = 0

The MCU can clear this bit by writing a 1. (Writing a 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

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

SUSR = 1

Function suspend is detected.

7

RSTR

0

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

by a USB function reset.

RSTR = 0

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

RSTR = 1

Function reset is detected.