SH7670 Datasheet, PDF (843/1292 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7670 Series

Section 17 USB 2.0 Host/Function Module (USB)
S
S
SOD
S
SOD S
SOD
O
O
OU A
O
OUA O
OUA
USB bus
F
F
FTT
F
A
0
FTT F
A
0
FTT
A
0
PID bit setting
Token
NAK
BUF
Token
Token
not issued not issued
BUF
Token
issued
BUF
Token
not issued
BUF
Token
issued
BUF
Token
not issued
BUF
Token
issued
Interval counter started
Figure 17.13 Token Issuance when IITV = 1
When the selected pipe is for isochronous transfers, this module carries out the operation below in
addition to controlling token issuance interval. This module issues a token even when the NRDY
interrupt generation condition is satisfied.
(i) When the selected pipe is for isochronous IN transfers
This module generates the NRDY interrupt when this module issues the IN token but does not
receive a packet successfully from a peripheral device (no response or packet error).
This module sets the OVRN bit to 1 generating the NRDY interrupt when the time to issue an IN
token comes in a state in which this module cannot receive data because the FIFO buffer is full
(due to the fact that software (DMAC) is too slow to read data from the FIFO buffer),
(ii) When the selected pipe is for isochronous OUT transfers
This module sets the OVRN bit to 1 generating the NRDY interrupt and transmitting a zero-length
packet when the time to issue an OUT token comes in a state in which there is no data to be
transmitted in the FIFO buffer (because software (DMAC) is too slow to write data to the FIFO
buffer).
The token issuance interval is reset on any of the following conditions.
 When a hardware-reset is applied to this module (here, the IITV bits are also cleared to 0).
 When software sets the ACLRM bit to 1.
Rev. 1.00 Nov. 14, 2007 Page 817 of 1262
REJ09B0437-0100