FlexRay Module Registers
1336
SPNU563A – March 2018
Copyright © 2018, Texas Instruments Incorporated
FlexRay Module
Table 26-93. Test Register 1 (TEST1) Field Descriptions (continued)
Bit
Field
Value
Description
5-4
TMC
Test mode control.
0
Normal operation mode, default.
1h
RAM test mode. All RAM blocks of the FlexRay module are directly accessible by the host. This
mode is intended to enable testing of the embedded RAM blocks during production testing.
2h
I/O test mode. The output pins txd1, txd2, txen1, txen2 are driven to the values defined by bits
TXA, TXB, TXENA, TXENB. The values applied to the input pins rxd1, rxd2 can be read from
register bits RXA, RXB.
3h
Unused. Mapped to normal operation mode.
3-2
Reserved
0
Reads return 0. Writes have no effect.
1
ELBE
External Loop Back Enable. There are two possibilities to perform a loop back test. External loop
back via physical layer or internal loop back for in-system self-test (default). In case of an internal
loop back pins txen1,2 are in their inactive state, pins txd1,2 are set to HIGH, pins rxd1,2 are not
evaluated. Bit ELBE is evaluated only when POC is in loop back mode and test mode control is in
normal operation mode TMC = 00.
0
Internal loop back (default).
1
External loop back.
0
WRTEN
Write test register enable. Enables write access to the test registers. To set the bit from 0 to 1, the
test mode key has to be written as defined in Lock Register (LCK). The unlock sequence is not
required when WRTEN is kept at 1 while other bits of the register are changed. The bit can be
reset to 0 at any time.
0
Write access to the test register is disabled.
1
Write access to the test register is enabled.
26.3.2.1.5.1 Asynchronous Transmit Mode (ATM)
The asynchronous transmit mode is entered by writing 1110 to the controller host interface command
vector CMD in the SUC configuration register 1 (controller host interface command: ATM) while the
communication controller is in CONFIG state and bit WRTEN in the test register 1 is set to 1. When called
in any other state or when bit WRTEN is not set, CMD will be reset to 0000 = command_not_accepted.
POCS in the communication controller status vector will show 00 1110 while the FlexRay module is in
ATM mode.
Asynchronous transmit mode can be left by writing 0001 (controller host interface command: CONFIG) to
the controller host interface command vector CMD in the SUC configuration register 1.
In ATM mode transmission of a FlexRay frame is triggered by writing the number of the corresponding
message buffer to the input buffer command request register while bit STXR in the input buffer command
mask register is set to 1. In this mode wakeup, startup, and clock synchronization are bypassed, the
controller host interface command SEND_MTS results in the immediate transmission of a MTS symbol.
MTS symbols received while operating in ATM mode will set the status interrupt flags MTSA,B in the
Status Interrupt Register like in monitor mode.
26.3.2.1.5.2 Loop Back Mode
The loop back mode is entered by writing 1111 to the controller host interface command vector CMD(3-0)
in the SUC configuration register 1 (controller host interface command: LOOP_BACK) while the
communication controller is in CONFIG state and bit WRTEN in the test register 1 is set to 1. This write
operation has to be directly preceded by two consecutive write accesses to the Configuration Lock Key
(unlock sequence). When called in any other state or when bit WRTEN is not set, CMD will be reset to
0000 = command_not_accepted. POCS in the communication controller status vector will show 00 1101
while the FlexRay module is in loop back mode.
Loop back mode can be left by writing 0001 (controller host interface command: CONFIG) to the controller
host interface command vector CMD in the SUC configuration register 1.