SH7670 Datasheet, PDF (831/1292 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7670 Series

Section 17 USB 2.0 Host/Function Module (USB)
(b) Data Stage
Data transfers are done using the DCP buffer memory.
The access direction of the DCP buffer memory should be specified using the ISEL bit in
CFIFOSEL.
For the first data packet of the data stage, the data PID must be transferred as DATA1. Transaction
is done by setting the data PID = DATA1 and the PID bit = BUF using the SQSET bit in
DCPCFG. Completion of data transfer is detected using the BRDY and BEMP interrupts.
Setting continuous transfer mode allows data transfers over multiple packets. Note that when
continuous transfer mode is set for the receiving direction, the BRDY interrupt is not generated
until the buffer becomes full or a short packet is received (the integer multiple of the maximum
packet size, and less than 256 bytes).
For control write transfers, when the number of data bytes to be sent is the integer multiple of the
maximum packet size, software must control so as to send a zero-length packet at the end.
(c) Status Stage
Zero-length packet data transfers are done in the direction opposite to that in the data stage. As
with the data stage, data transfers are done using the DCP buffer memory. Transactions are done
in the same manner as the data stage.
For the data packets of the status stage, the data PID must be transferred as DATA1. The data PID
should be set to DATA1 using the SQSET bit in DCPCFG.
For reception of a zero-length packet, the received data length must be confirmed using the DTLN
bits in CFIFOCTR after the BRDY interrupt is generated, and the buffer memory must then be
cleared using the BCLR bit.
Rev. 1.00 Nov. 14, 2007 Page 805 of 1262
REJ09B0437-0100