SH7205 Datasheet, PDF (1265/1904 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7200 Series

Section 24 USB 2.0 Host/Function Module (USB)
The interval error detection interval bits (IITV) are explained below.
(1) When the Host Controller Function is Selected
The IITV bits can be set when the selected pipe is specified for isochronous transfer or interrupt
transfer. This module controls the intervals of token issuance according to the setting of this bit. It
issues a token for the selected pipe once in 2^IITV (micro) frames.
This module counts 1-ms frames to measure the interval for the pipe used for communication with
a full-speed/low-speed function device connected to a high-speed hub.
This module starts counting for token issuance intervals from the first (micro) frame that comes
after the PID bits have been set to BUF.
USB bus
PID bit setting
Token issuance
(0: Issued
-: Not issued)
Start of interval
counting
S
S
O
O
F
F
NAK
-
BUF
-
SODSOD
OUAOUA
FTTFTT
A
A
0
0
BUF
BUF
0
0
↑
Figure 24.1 Whether a Token is Issued or Not when IITV = 0
USB bus
PID bit setting
Token issuance
(0: Issued
-: Not issued)
Start of interval
counting
S
O
F
NAK
-
S
O
F
BUF
-
SODS
OUAO
FTTF
A
0
BUF
0
BUF
-
SODS
OUAO
FTTF
A
0
BUF
BUF
0
-
↑
SOD
OUA
FTT
A
0
BUF
0
Figure 24.2 Whether a Token is Issued or Not when IITV = 1
Rev. 1.00 Mar. 25, 2008 Page 1233 of 1868
REJ09B0372-0100