Operation On Receiving An Out Token (Endpoints 0, 2, And 5); Figure 18.6 Operation On Receiving An Out Token (Ep2-Out: Initial Fifo Is Empty) - Renesas H8S/2158 User Manual

Section 18 Universal Serial Bus Interface (USB)
18.4.3

Operation on Receiving an OUT Token (Endpoints 0, 2, and 5)

Figures 18.6 to 18.9 show the USB function core and LSI firmware operations when the USB
function core receives an OUT token (OUT transaction). An OUT transaction is used for data
stage and status stage of control transfer, interrupt transfer, and bulk transfer.
USB Host
Send an OUT
token packet
Send an OUT data
packet (8 bytes)
Receive an ACK
handshake packet
Note: * When an EP2TS interrupt is specified as a USBIB or USBIC interrupt according to the INTSELR0 setting, the corresponding
interrupt occurs. In this case, if a USBIB or USBIC interrupt occurs, interrupt source determination process is not required.
(Note that TSFR0 must be accessed to clear the flags.)

Figure 18.6 Operation on Receiving an OUT Token (EP2-OUT: Initial FIFO Is Empty)

Rev. 3.00 Jan 25, 2006 page 610 of 872
REJ09B0286-0300
USB Function Core
Receive an OUT
token packet
Receive an OUT data
packet (8 bytes)
Send ACK to
the host
Send ACK to
the slave CPU
Core Interface
Write data to EP2 FIFO
Modify FVSR2
Request an USBID
interrupt (EP2TS)
Modify FVSR2
Slave CPU
Initiate the USBID
interrupt processing
Read USBIFR0 and check
if a TS interrupt occurs
or not
Read TSFR0 and check if
an EP2TS interrupt occurs
or not
Read FVSR2 and check
if the EP2 FIFO contains
8-byte data
Read EPDR2
Clear the EP2TS bit of
TSFR0 to 0
Complete the USBID
interrupt processing