Datasheet

Universal Serial Bus Module (USB)
I/O Registers
MC68HC908JB8•MC68HC08JB8•MC68HC08JT8 — Rev. 2.3 Technical Data
Freescale Semiconductor Universal Serial Bus Module (USB) 149
9.8.8 USB Control Register 3
TX1ST — Endpoint 0 Transmit First Flag
This read-only bit is set if the endpoint 0 data transmit flag (TXD0F) is
set when the USB control logic is setting the endpoint 0 data receive
flag (RXD0F). In other words, if an unserviced endpoint 0 transmit flag
is still set at the end of an endpoint 0 reception, then this bit will be set.
This bit lets the firmware know that the endpoint 0 transmission
happened before the endpoint 0 reception.
Reset clears this bit.
1 = IN transaction occurred before SETUP/OUT
0 = IN transaction occurred after SETUP/OUT
TX1STR — Clear Endpoint 0 Transmit First Flag
Writing a logic 1 to this write-only bit will clear the TX1ST bit if it is set.
Writing a logic 0 to the TX1STR has no effect. Reset clears this bit.
OSTALL0 — Endpoint 0 Force STALL Bit for OUT token
This read/write bit causes endpoint 0 to return a STALL handshake
when polled by an OUT token by the USB host controller. Reset
clears this bit.
1 = Send STALL handshake
0 = Default
Address: $001A
Bit 7654321Bit 0
Read:
TX1ST 0
OSTALL0 ISTALL0
0
PULLEN ENABLE2 ENABLE1
Write:
TX1STR
Reset:000000*00
= Unimplemented
* PULLEN bit is reset by POR or LVI reset only.
Figure 9-22. USB Control Register 3 (UCR3)