Datasheet

Universal Serial Bus Module (USB)
USB Interrupts
MC68HC908JB8•MC68HC08JB8•MC68HC08JT8 — Rev. 2.3 Technical Data
Freescale Semiconductor Universal Serial Bus Module (USB) 161
9.9.1.3 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 9-32.
Figure 9-32. IN Token Data Flow for Transmit Endpoint 1
VALID IN TOKEN
RECEIVED FOR ENDPOINT 1
SEND STALL
HANDSHAKE
SET TXD1F TO 1
(TXD1IE = 1)
NO INTERRUPT
SEND DATA
N
DATA PID SET BY T1SEQ
USB MODULE ENABLED?
(USBEN = 1)
TRANSMIT ENDPOINT NOT STALLED
BY FIRMWARE (STALL1 = 1)?
TRANSMIT ENDPOINT READY TO TRANSFER?
(TX1E = 1) AND (TXD1F = 0) AND (UE1TR = 0)
TRANSMIT ENDPOINT ENABLED?
(ENABLE = 1)
TRANSMIT ENDPOINT
INTERRUPT ENABLED?
VALID TRANSACTION
INTERRUPT GENERATED
SEND NAK
HANDSHAKE
NO RESPONSE
FROM USB FUNCTION
Y
Y
Y
Y
Y
Y
N
N
N
N
N
Y
NO RESPONSE
FROM USB FUNCTION
ACK RECEIVED AND NO
TIMEOUT CONDITION OCCURS?
NO RESPONSE
FROM USB FUNCTION