SH7203 Datasheet, PDF (1215/1686 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7200 Series

Section 23 USB 2.0 Host/Function Module (USB)
(4) Response PID
The PID bits in DCPCTR and PIPEnCTR are used to set the response PID for each pipe.
The following shows this module operation with various response PID settings:
• Response PID settings when the host controller function is selected:
The response PID is used to specify the execution of transactions.
A. NAK setting: Using pipes is disabled. No transaction is executed.
B. BUF setting: Transactions are executed based on the status of the buffer memory.
For OUT direction: If there are transmit data in the buffer memory, an OUT token is
issued.
For IN direction: If there is an area to receive data in the buffer memory, an IN token is
issued.
C. STALL setting: Using pipes is disabled. No transaction is executed.
Setup transactions for the DCP are set with the SUREQ bit.
• Response PID settings when the function controller function is selected:
The response PID is used to specify the response to transactions from the host.
A. NAK setting: The NAK response is always returned in response to the generated
transaction.
B. BUF setting: Responses are made to transactions based on the status of the buffer memory.
C. STALL setting: The STALL response is always returned in response to the generated
transaction.
For setup transactions, an ACK response is always returned, regardless of the PID setting, and the
USB request is stored in the register.
This module may carry out writing to the PID bits, depending on the results of the transaction.
• When the host controller function has been selected and the response PID is set by hardware:
A. NAK setting: In the following cases, PID = NAK is set and issuing of tokens is
automatically stopped:
• When a transfer other than isochronous transfer has been performed and no response is
returned to the issued token.
• When a corrupted packet is received in response to the transmitted token.
• When a short packet is received in the data stage of a control read transfer.
Rev. 2.00 Apr. 16, 2008 Page 1185 of 1652
REJ09B0313-0200