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Universal Serial Bus Interface – On-The-Go Module
10-68
Freescale Semiconductor
NOTE
For TX-ISO, MULT counter can be loaded with a lesser value in the dTD
multiplier override field. If the multiplier override field is zero, the MULT
counter initializes to the multiplier in the QH.
•
RX packet retired:
— MULT counter reaches zero.
— Non-MDATA data PID is received
— Overflow error:
– Packet received is > maximum packet length. (Buffer Error bit is set)
– Packet received exceeds total bytes allocated in dTD. (Buffer Error bit is set)
— Fulfillment error (Transaction Error bit is set):
– # packets occurred > 0 AND # packets occurred < MULT
— CRC error (Transaction Error bit is set)
NOTE
For ISO, when a dTD is retired, the next dTD is primed for the next frame.
For continuous (micro)frame to (micro)frame operation, DCD must ensure
the dTD linked-list is out ahead of the device controller by at least two
(micro)frames.
Isochronous Pipe Synchronization
When it is necessary to synchronize an isochronous data pipe to the host, the (micro)frame number
(FRINDEX register) can act as a marker. To cause a packet transfer to occur at a specific (micro)frame
number (N), the DCD must interrupt on SOF during frame N-1. When the FRINDEX equals N-1, the DCD
must write the prime bit. The USB OTG primes the isochronous endpoint in (micro)frame N-1 so the
device controller executes delivery during (micro)frame N.
CAUTION
Priming an endpoint towards the end of (micro)frame N-1 does not
guarantee delivery in (micro)frame N. The delivery may actually occur in
(micro)frame N+1 if the device controller does not have enough time to
complete the prime before the SOF for packet N is received.
Isochronous Endpoint Bus Response Matrix
Table 10-57. Isochronous Endpoint Bus Response Matrix
Token
Type
Stall
Not
Primed
Primed
Underflow
Overflow
Setup
STALL
STALL
STALL
N/A
N/A
In
NULL
1
Packet
NULL
Packet
Transmit
BS Error
2
N/A
Summary of Contents for MCF54455
Page 33: ...xxviii Freescale Semiconductor ...
Page 67: ...Freescale Semiconductor 1 ...
Page 125: ...Freescale Semiconductor 1 ...
Page 145: ...Enhanced Multiply Accumulate Unit EMAC 5 21 Freescale Semiconductor ...
Page 173: ...Cache 6 28 Freescale Semiconductor ...
Page 179: ...Static RAM SRAM 7 6 Freescale Semiconductor ...
Page 207: ...Power Management 9 16 Freescale Semiconductor ...
Page 323: ...Reset Controller Module 13 8 Freescale Semiconductor ...
Page 389: ...Pin Multiplexing and Control 16 44 Freescale Semiconductor ...
Page 575: ...PCI Bus Controller 22 58 Freescale Semiconductor ...
Page 600: ...Advanced Technology Attachment ATA Freescale Semiconductor 23 25 ...
Page 601: ...Freescale Semiconductor 1 ...
Page 842: ...I2 C Interface Freescale Semiconductor 33 16 ...
Page 843: ...Freescale Semiconductor 1 ...
Page 921: ...Revision History A 6 Freescale Semiconductor ...