M68HC08 datasheet(167/288 Pages) FREESCALE

167 / 288 page

Universal Serial Bus Module (USB)

MC68HC908BD48 — Rev. 2.1

Data Sheet

Freescale Semiconductor

Universal Serial Bus Module (USB)

167

TBEF — Transmit Buffer Empty Flag

This flag is set after the data stored in endpoint 0 transmit buffer has

been sent and ACK handshake packet is received. Software must

clear this flag by writing a logic "1" to TBEFR bit after the data is ready

in the transmit buffer. This enables the next data packet transmission

when endpoint 0 transmit is enabled (TX0E = 1). TBEF generates an

interrupt request to the CPU if the TBIE bit is also set. Reset clears

this bit.

1 = Transmit on endpoint 0 has occurred

0 = Transmit on endpoint 0 has not occurred

RBFF — Receive Buffer Full Flag

This flag is set when the module has received one data packet and

replied with ACK handshake packet. Software must clear this flag by

writing "1" to RBFFR bit after all the received data have been read to

enable the next data packet reception. RBFF generates an interrupt

request to the CPU if the RBIE bit is also set. Reset clears this bit.

1 = Receive on endpoint 0 has occurred

0 = Receive on endpoint 0 has not occurred

EOPIF — End Of Packet Interrupt Flag

This flag is set when a valid EOP signal transition is detected on the

D+ and D– lines. This flag can be cleared by writing "1" to EOPIFR bit.

EOPIF generates an interrupt request to the CPU if the EOPIE bit is

also set. Reset clears this bit.

1 = End-of-packet sequence has been detected

0 = End-of-packet sequence has not been detected

RSTIF — Reset Interrupt Flag

The flag is set when a valid reset signal state is detected on the D+

and D– lines. This flag can be cleared by writing "1" to RSTIFR bit.

RSTIF generates an interrupt request to the CPU if the RSTIE bit is

also set. Reset clears this bit.

1 = USB reset condition has been detected

0 = USB reset condition has not been detected

M68HC08 Datasheet(PDF) 167 Page - Freescale Semiconductor, Inc