MC68HC908BD48 Datasheet, PDF (173/290 Pages) Freescale Semiconductor, Inc – Microcontrollers

Universal Serial Bus Module (USB)
Registers
If all the conditions for a successful endpoint 2 USB response to a
host’s IN token are satisfied (TXD1F = 0, TX1E = 1, STALL2 = 0,
ENABLE2 = 1), but endpoint 1 is selected (ENDADD = 0), the module
will respond with an NAK handshake packet. Reset clears this bit.
1 = The transmit buffer is used for endpoint 2
0 = The transmit buffer is used for endpoint 1
TX1E — Endpoint 1/2 Transmit Enable
This bit is set to enable data packet transmission from endpoint 1/2.
Software should set this bit when data is ready for data packet
transmission. It must be cleared when no more data needs to be
transmitted. If TX1E is "0" or TXD1F is "1", a NAK handshake will be
returned for the next IN token. Reset clears this bit.
1 = Data is ready to be sent on endpoint 1/2
0 = Data is not ready; respond with ACK
FRESUM — Force Resume
This bit is set to force a resume state on USB bus lines until software
clears this bit. Before setting the FRESUM bit, the SUSPND bit must
to be cleared in order to drive the USB bus lines. Setting the FRESUM
bit will not cause RESUMF to be set. Reset clears this bit.
1 = Resume state forced on USB bus; only if SUSPND is cleared
0 = No effect
TP1SIZ[3:0] — Endpoint 1/2 Transmit Data Size
The TP1SIZ[3:0] is used to store the number of transmit data bytes
from endpoint 1/2. The default size of transmit data is "0" after reset.
MC68HC908BD48 — Rev. 1.0
MOTOROLA
Universal Serial Bus Module (USB)
Technical Data
173