MC68HC908LD64 Datasheet, PDF (214/362 Pages) Freescale Semiconductor, Inc – Microcontrollers

Universal Serial Bus Module (USB)
TX0E — Embedded Device Endpoint 0 Transmit Enable
This read/write bit enables a transmit to occur when the USB host
controller sends an IN token to the embedded device endpoint 0.
Software should set this bit when data is ready to be transmitted. It
must be cleared by software when no more embedded device
endpoint 0 data needs to be transmitted. If this bit is 0 or the TXD0F
is set, the USB will respond with a NAK handshake to any embedded
device endpoint 0 IN tokens. Reset clears this bit.
1 = Data is ready to be sent
0 = Data is not ready; respond with NAK
RX0E — Embedded Device Endpoint 0 Receive Enable
This read/write bit enables a receive to occur when the USB host
controller sends an OUT token to the embedded device endpoint 0.
Software should set this bit when data is ready to be received. It must
be cleared by software when data cannot be received. If this bit is 0
or the RXD0F is set, the USB will respond with a NAK handshake to
any embedded device endpoint 0 OUT tokens. Reset clears this bit.
1 = Data is ready to be received
0 = Not ready for data; respond with NAK
TP0SIZ[3:0] — Embedded Device Endpoint 0 Transmit Data Packet Size
These read/write bits store the number of transmit data bytes for the
next IN token request for embedded device endpoint 0. These bits are
cleared by reset.
Data Sheet
214
Universal Serial Bus Module (USB)
MC68HC908LD64 — Rev. 3.0
Freescale Semiconductor