TC1796
Peripheral Units (Vol. 2 of 2)
Micro Link Interface (MLI)
User’s Manual
23-45
V2.0, 2007-07
MLI, V2.0
23.2.2.2 Non-Acknowledge Error
A Non-Acknowledge error condition is detected by the transmitter when at the end of a
frame transmission, the TREADY signal is still at high level (TREADY = 1 when TVALID
becomes 0). In this case, the error flag TSTATR.NAE is set and the maximum Non-
Acknowledge error counter TCR.MNAE is decremented by 1. If a Non-Acknowledge
error condition is detected and TCR.MNAE is becoming 0 or while it is already 0, a time-
out event is generated by setting bit TISR.TEI (see
on
) and an
MLI service request is generated if enabled by TIER.TEIE = 1. The Non-Acknowledge
error flag TSTATR.NAE is cleared by hardware when a frame transmission has been
acknowledged correctly. It can also be cleared by software when writing a 1 to bit
SCR.CNAE.
The Non-Acknowledge error counter TCR.MNAE is automatically set to 11
B
when a
frame has been acknowledged correctly. It can be read and written by software, allowing
a limited number of consecutive Non-Acknowledge errors to be defined that can be
detected until a time-out event is generated. If, for example, the first occurrence of a Non-
Acknowledge error should lead to a time-out event, bit TCR.MNAE has to be written by
software with 00
B
or 01
B
after each correctly received frame.
23.2.2.3 Address Prediction
An address prediction method can be enabled to support communication between MLI
transmitter and MLI receiver without sending address offset information in the frames to
optimize the required MLI bandwidth. This feature reduces the required bandwidth for
MLI communication. Both communication partners, MLI transmitter and the MLI receiver
are able to detect regular offset differences of consecutive window accesses to the same
window. The address prediction mechanism working independently for each pipe,
different prediction values can be handled in parallel for the different pipes.
Transmitting Controller
If the address prediction method is enabled (TCR.NO = 0), the MLI transmitter compares
the offset of each Transfer Window read or write access with the offset of the previous
access to the same Transfer Window (stored in TPxAOFR.AOFF). The result of this
comparison is stored in two’s complement representation in TPxSTATR.AP (limited to 9
bits, otherwise prediction is not possible). Between the accesses to a specific window,
other windows can be accessed without disturbing the prediction.
If the offset differences are identical in at least two consecutive accesses to the same
Transfer Window, an address prediction is possible (flag TPxSTATR.OP becomes set)
and optimized frames can be sent to the receiving controller for this pipe. If the offset
difference of a next access to the same Transfer Window does not match the calculated
value in TPxSTATR.AP, flag TPxSTATR.OP is cleared and address prediction is not
possible. In this case, a Normal Frame for writing or reading (Write Offset and Data
Frame or Discrete Read Frame) is started.
