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Section 26 USB 2.0 Host/Function Module
R01UH0134EJ0400 Rev. 4.00 Page 1537 of 2108
Sep 24, 2014
SH7262 Group, SH7264 Group
Interval counter started
USB bus
PID bit setting
NAK
S
O
F
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O
F
S
O
F
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O
F
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O
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O
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BUF BUFBUF BUF BUF BUF
D
A
T
A
0
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0
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A
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O
U
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Token
not issued
Token
not issued
Token
not issued
Token
not issued
Toke n
Token
issued
Token
issued
Token
issued
Figure 26.17 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.
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 (because data is read from the FIFO buffer too late).
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 data is written to the FIFO buffer too late ).
The token issuance interval is reset when a power-on reset is applied or the ACLRM bit is set
to 1.