Figure 679. Bist Test Data Frame - ST STM32G4 Series Reference Manual

RM0440
Collision avoidance
The physical layer respects a delay, "tInterFrameGap", between end of last transmitted bit of
a Tx message, and the first bit of a following message.
It also checks the "Idle" state of the CC line before starting transmission. The definition of
"idle" is less than "nTransitionCount" (i.e. 3) transitions in "tTransitionWindow" (i.e. 12 to 20
μs). For collision avoidance in PD3.0 it is also necessary to manage Rd value (source) and
monitor Type-C voltage level for these Rp modifications (at the sink).
Physical layer signaling schemes
The BMC scheme is implemented.
BIST: General
Depending on the BIST action required by the Protocol Layer, either of the following can be
run:
–
–
The two possible patterns supported in UCPD (corresponding to "BMC" mode) are:
–
–
BIST pattern option 1: Test Data pattern
Note that the Test Data pattern is not viewed as a special case in UCPD.
The BIST Test Data packet frame format is shown in
Preamble (training for receiver)
LEGEND:
Preamble, not encoded with 4b5b
This is a fixed length test data pattern. In reality the only aspect that marks its difference
from the general packet format already shown in
of the Header. As UCPD receives the Tx Header contents via programming (it is simply
a Tx BIST pattern test, achieved by writing TXMODE and TXSEND
an Rx BIST pattern test, achieved by writing RXMODE to the correct value for
RXBIST.
BIST Test Data (192 bit pattern), applies to Tx and Rx. In the case of Rx, the
message will be received (but discarded rather than passing to the protocol layer,
which must nevertheless still generate a GoodCRC Tx message in
acknowledgment).
BIST Carrier Mode 2 (single pattern, infinite length message), applies to Tx only,
the Rx opposite a Tx in this mode should simply ignore the CC line during this
state.

Figure 679. BIST Test Data Frame

SOP* (start of packet)
... CRC
Provided by the Physical layer,
USB Type-C™ / USB Power Delivery interface (UCPD)
Figure
Header BIST Test Data
Data objects=7
EOP (end of packet)
encoded with 4b5b
Figure 676: Packet format
RM0440 Rev 1
679:
BIST test data (192 bits)...
BDO
Provided by the Protocol layer,
encoded with 4b5b
is the contents
MSv45542V1
2009/2083
2040