OBCM
OBCR
1 0
2
4 3
5
20 19
21
17 16
18
1 0
15
17 16
8
9
1 0
2
4 3
5
view
request
1 0
view
request
internal storage
internal storage
6
22
6
Host
Message
RAM
FlexRay
OBF
OBF
Sha-
dow
OBF = Output Buffer
Host
Module Operation
1255
SPNU563A – March 2018
Copyright © 2018, Texas Instruments Incorporated
FlexRay Module
Figure 26-20. Double Buffer Structure Output Buffer
OBF host and OBF shadow as well as bits OBCM.RHSS, OBCM.RDSS, OBCM.RHSH, OBCM.RDSH
from the output buffer command mask register and bits OBCM.OBRS(6-0), OBCM.OBRH(6-0) from the
output buffer command request register are swapped under control of bits OBCR.VIEW and OBCR.REQ
from the output buffer command request register.
Writing bit OBCR.REQ in the output buffer command request register to 1 copies bits OBCM.RHSS,
OBCM.RDSS from the output buffer command mask register and bits OBCR.OBRS(6-0) from the output
buffer command request register to an internal storage (see
After setting OBCR.REQ to 1, OBCR.OBSYS is set to 1, and the transfer of the message buffer selected
by OBCR.OBRS(6-0) from the message RAM to OBF shadow is started. After the transfer between the
message RAM and OBF shadow has completed, the OBCR.OBSYS bit is set back to 0. Bits OBCR.REQ
and OBCR.VIEW can only be set to 1 while OBCR.OBSYS is 0.
Figure 26-21. Swapping of OBCM and OBCR Bits
OBF host and OBF shadow are swapped by setting bit OBCR.VIEW in the output buffer command request
register to 1 while bit OBCR.OBSYS is 0 (see
).