SH7764 Datasheet, PDF (1046/1752 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC Engine Family SH-4A Series

Section 21 USB 2.0 Host/Function Module (USB)
The interval counter is not initialized under the conditions noted below.
3. When the PID bit is set to NAK or STALL
The interval timer does not stop. This module attempts the transactions at the subsequent
interval.
4. The USB bus reset or the USB is suspended
The IITV bit is not initialized. When the SOF has been received, the counter is restarted from
the value prior to the reception of the SOF.
(b) Interval Counting and Transfer Control when the Host Controller Function is Selected
This module controls the interval between token issuance operations based on the IITV bit
settings. Specifically, this module issues a token for a selected pipe once every 2IITV (µ) frames.
This module counts the interval every 1-ms frame for the pipes used for communications with the
full-speed peripheral devices connected to a high-speed HUB.
This module starts counting the token issuance interval at the (µ) frame following the (µ) frame in
which software has set the PID bits to BUF.
S
S
SOD SOD
O
O
OU A OU A
USB bus
F
F
FTT
A
FT T
A
0
0
PID bit setting
Token
NAK
BUF
Token
Token
not issued not issued
BUF
Token
issued
BUF
Token
issued
Interval counter started
Figure 21.12 Token Issuance when IITV = 0
Rev. 1.00 Nov. 22, 2007 Page 990 of 1692
REJ09B0360-0100