MC908JB16DWE Datasheet, PDF (205/332 Pages) Freescale Semiconductor, Inc – Microcontrollers

Universal Serial Bus Module (USB)
11.9.1.3 Transmit Endpoint 1
For an IN transaction directed at endpoint 1, the USB module will
generate an interrupt by setting the TXD1F in the UIR1 register. The
conditions necessary for the interrupt to occur are shown in
Figure 11-32.
VALID IN TOKEN
RECEIVED FOR ENDPOINT 1
Y
USB MODULE ENABLED?
N
(USBEN = 1)
Y
TRANSMIT ENDPOINT NOT STALLED N
BY FIRMWARE (STALL1 = 1)?
Y
TRANSMIT ENDPOINT READY TO TRANSFER? N
(TX1E = 1) AND (TXD1F = 0) AND (UE1TR = 0)
Y
TRANSMIT ENDPOINT ENABLED?
N
(ENABLE = 1)
Y
SEND DATA
DATA PID SET BY T1SEQ
ACK RECEIVED AND NO
N
TIMEOUT CONDITION OCCURS?
Y
SET TXD1F TO 1
NO RESPONSE
FROM USB FUNCTION
SEND STALL
HANDSHAKE
SEND NAK
HANDSHAKE
NO RESPONSE
FROM USB FUNCTION
NO RESPONSE
FROM USB FUNCTION
TRANSMIT ENDPOINT
N
INTERRUPT ENABLED?
(TXD1IE = 1)
Y
VALID TRANSACTION
INTERRUPT GENERATED
NO INTERRUPT
Figure 11-32. IN Token Data Flow for Transmit Endpoint 1
MC68HC908JB16 — Rev. 1.1
Freescale Semiconductor
Universal Serial Bus Module (USB)
Technical Data
205