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Section 26 USB 2.0 Host/Function Module
R01UH0134EJ0400 Rev. 4.00 Page 1531 of 2108
Sep 24, 2014
SH7262 Group, SH7264 Group
(b) Operation when Transmission/Reception is Impossible at Token Issuance Timing
This module cannot issue tokens even at token issuance timing in the following cases. In such a
case, this module attempts transactions at the subsequent interval.
When the PID is set to NAK or STALL.
When the buffer memory is full at the token sending timing in the receiving (IN) direction.
When there is no data to be sent in the buffer memory at the token sending timing in the
sending (OUT) direction.
26.4.8 Isochronous Transfers (PIPE1 and PIPE2)
This module has the following functions pertaining to isochronous transfers.
1. Notification of isochronous transfer error information
2. Interval counter (specified by the IITV bit)
3. Isochronous IN transfer data setup control (IDLY function)
4. Isochronous IN transfer buffer flush function (specified by the IFIS bit)
This module does not support the High Bandwidth transfers of isochronous transfers.
When using more than one pipe simultaneously for isochronous transfers, follow the packet
constraints provided in section 5.6.3, Isochronous Transfer Packet Size Constraints, in Universal
Serial Bus Revision 2.0 Specification.
(1) Error Detection with Isochronous Transfers
This module has a function for detecting the error information noted below, so that when errors
occur in isochronous transfers, software can control them. Tables 26.27 and 26.28 show the
priority in which errors are confirmed and the interrupts that are generated.
(a) PID errors
If the PID of the packet being received is illegal
(b) CRC errors and bit stuffing errors
If an error occurs in the CRC of the packet being received, or the bit stuffing is illegal
(c) Maximum packet size exceeded
The maximum packet size exceeded the set value.