Renesas R5S72621 User Manual

Page of 2152
 
Section 26   USB 2.0 Host/Function Module 
Page 1528 of 2108 
 
R01UH0134EJ0400  Rev. 4.00 
 
 Sep 
24, 
2014 
SH7262 Group, SH7264 Group
26.4.6
 
Bulk Transfers (PIPE1 to PIPE5) 
The buffer memory specifications for bulk transfers (single/double buffer setting, or 
continuous/non-continuous transfer mode setting) can be selected. The maximum size that can be 
set for the buffer memory is 2 Kbytes. The buffer memory state is controlled by this module, with 
a response sent automatically for a PING packet/NYET handshake. 
(1)  PING Packet Control when the Host Controller Function is Selected 
This module automatically sends a PING packet in the OUT direction. 
On receiving an ACK handshake in the initial state in which PING packet sending mode is set, 
this module sends an OUT packet as noted below. The module returns to PING packet sending 
mode when a NAK or NYET is received during an OUT transaction. 
1.  Sets OUT data sending mode. 
2.  Sends a PING packet. 
3.  Receives an ACK handshake. 
4.  Sends an OUT data packet. 
5.  Receives an ACK handshake. 
(Repeats steps 4 and 5.) 
6.  Sends an OUT data packet. 
7.  Receives an NAK/NYET handshake. 
8.  Sends a PING packet. 
 
This module is returned to PING packet sending mode by a power-on reset, receiving a 
NYET/NAK handshake, clearing the sequence toggle bits (SQCLR), and setting the buffer clear 
bit (ACLRM) in PIPEnCTR.