Module Operation
1220
SPNU563A – March 2018
Copyright © 2018, Texas Instruments Incorporated
FlexRay Module
26.2.1.1.1.3 Transfer Reset
The Transfer Unit State Machine can be reset by the Transfer Unit Enable (TUE) bit in the Global Control
register. Though the Transfer Unit State Machine can be reset with the above, the module register
contents and the Transfer Configuration RAM (TCR). So, after re-enabling the Transfer Unit no
reconfiguration of the Transfer Unit is required.
26.2.1.1.1.4 Transfer Modes
Possible transfer sequence modes are:
•
Manual by triggering the desired transfer by setting the corresponding bit in the Trigger Transfer to
System Memory (TTSM) register or the Trigger Transfer to Communication Controller (TTCC) register
•
Event-Driven (transfers from FlexRay Communication Controller to the System Memory only) using the
Enable Transfer on Event to System Memory (ETESM) register.
•
Single or continuous event driven transfers by using the Clear on Event to System Memory (CESM)
The transfer event trigger in general occurs upon completion of a reception or transmission of a frame
through the FlexRay bus.
shows more details: Conditions marked with 'X' per row must match
to trigger a FTU transfer event as configured in the Transfer Configuration RAM (TCR):
Table 26-2. FlexRay Transfer Unit Event Trigger Conditions
Event on
Channel A
Event on
Channel B
Frame belonging
to static segment
or first slot of
dynamic segment
Frame belonging
to dynamic
segment, except
first slot of
dynamic segment
Bus activity
detected on
Channel A
(MBS.ESA = 0)
Bus activity
detected on
Channel B
(MBS.ESB = 0)
FTU Event Trigger
for Receive
Message Buffers
X
X
X
X
X
X
X
X
X
X
FTU Event Trigger
for Transmit
Message Buffers
X
X
X
X
NOTE:
By setting the corresponding bit in the Enable Transfer on Event to System Memory
(ETESM) register prior to an on-demand transfer to the Communication Controller by way of
the Trigger Transfer to Communication Controller (TTCC) register, an event-triggered
transmission back to the System Memory can be initiated, once the buffer has been sent out
on the FlexRay bus. This mechanism can be used, for instance, to automatically read back
the header status information to the system memory after a transmission occurred.
The transmission or reception of null frames in the static segment of a FlexRay
communication cycle triggers transfers of the transfer unit. The header and/or payload is
transferred to the system memory, if the corresponding bits THTSM and/or TPTSM in the
Transfer Configuration RAM (TCR) are set. If neither THTSM nor TPTSM bit is set in TCR,
neither header nor payload gets transferred. The corresponding bit in the Transfer to System
Memory Occurred register (TSMO) gets set in all cases.