MPC8536E-ANDROID Freescale Semiconductor, MPC8536E-ANDROID Datasheet - Page 1448

• Manufacturer Part Number: MPC8536E-ANDROID
• Description: HARDWARE/SOFTWARE ANDROID OS
• Manufacturer: Freescale Semiconductor
• Series: PowerQUICC ™r
• Type: MPUr

Specifications of MPC8536E-ANDROID

• Contents: Board
• For Use With/related Products: MPC8536
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Universal Serial Bus Interfaces
the endpoint if it is using a queue head. Maximum Length is defined as the minimum of Total Bytes to
Transfer and Maximum Packet Size. The Cerr field is not decremented for a packet babble condition (only
applies to queue heads). A babble condition also exists if IN transaction is in progress at High-speed EOF2
point. This is called a frame babble. A frame babble condition is recorded into the appropriate schedule
data structure. In addition, the host controller must disable the port to which the frame babble is detected.
USBSTS[UEI] (USB error interrupt) is set and if the USBINTR[UEE] (USB error interrupt enable) is set,
then a hardware interrupt is signaled to the system at the next interrupt threshold. The host controller must
never start an OUT transaction that babbles across a micro-frame EOF.
21.6.14.1.3 Data Buffer Error
This event indicates that an overrun of incoming data or a underrun of outgoing data has occurred for this
transaction. This would generally be caused by the host controller not being able to access required data
buffers in memory within necessary latency requirements. These conditions are not considered transaction
errors, and do not effect the error count in the queue head. When these errors do occur, the host controller
records the fact the error occurred by setting the Data Buffer Error bit in the queue head, iTD or siTD.
If the data buffer error occurs on a non-isochronous IN, the host controller will not issue a handshake to
the endpoint. This forces the endpoint to resend the same data (and data toggle) in response to the next IN
to the endpoint.
If the data buffer error occurs on an OUT, the host controller must corrupt the end of the packet so that it
cannot be interpreted by the device as a good data packet. Simply truncating the packet is not considered
acceptable. An acceptable implementation option is to 1's complement the CRC bytes and send them.
There are other options suggested in the transaction translator section of the USB Specification Revision
2.0.
21-114
When a host controller detects a data PID mismatch, it must either: disable
the packet babble checking for the duration of the bus transaction or do
packet babble checking based solely on Maximum Packet Size. The USB
core specification defines the requirements on a data receiver when it
receives a data PID mismatch (for example, expects a DATA0 and gets a
DATA1 or visa-versa). In summary, it must ignore the received data and
respond with an ACK handshake, in order to advance the transmitter's data
sequence.The EHCI interface allows system software to provide buffers for
a Control, Bulk or Interrupt IN endpoint that are not an even multiple of the
maximum packet size specified by the device. Whenever a device misses an
ACK for an IN endpoint, the host and device are out of synchronization with
respect to the progress of the data transfer. The host controller may have
advanced the transfer to a buffer that is less than maximum packet size. The
device re-sends its maximum packet size data packet, with the original data
PID, in response to the next IN token. In order to properly manage the bus
protocol, the host controller must disable the packet babble check when it
observes the data PID mismatch.
MPC8536E PowerQUICC III Integrated Processor Reference Manual, Rev. 1
NOTE
Freescale Semiconductor