DS80C390_00 Datasheet, PDF (93/155 Pages) Dallas Semiconductor – High-Speed Microcontroller User’s Guide Supplement

DS80C390 High-Speed Microcontroller User’s Guide Supplement
If WTOE=0 the processor is not permitted to overwrite this message
center, so it is only necessary to clear the DTUP bit after reading the
message center.
The state of the DTUP bit in the receive mode does not inhibit remote frame
request transmission in the receive mode. The only gating item for remote
frame transmission in the receive mode is that the MSRDY and MTRQ bits
must both be set.
T/ R =1 (transmit)
In this mode, software must set TIH =1 and clear DTUP = 0 prior to doing an
update of the associated message center. This prevents the CAN module from
transmitting the data while the microcontroller is updating it. Once the
microcontroller has finished configuring the message center, software must clear
TIH = 0 and set MSRDY=MTRQ =DTUP =1, to enable the CAN module to
transmit the data.
The CAN module will not clear the DTUP after the transmission, but the
microcontroller can verify that the transmission has been completed, by
checking the MTRQ bit, which will be cleared (MTRQ = 0) after the
transmission has been successfully completed.
CAN 1 Message Center 2 Control Register (C1M2C)
7
6
5
4
3
SFR ECh MSRDY ETI
ERI INTRQ EXTRQ
RW-0 RW-0 RW-0 RW-0 RC-0
2
MTRQ
R*-0
1
ROW/TIH
R*-0
0
DTUP
R*-0
R=Unrestricted Read, C=Clear Only, *= See description below, -n=Value after Reset
C1M2C
Bits 7-0
Operation of the bits in this register are identical to those found in the CAN 1
Message One Control Register (C1M1C;ABh). Please consult the description
of that register for more information.
CAN 1 Message Center 3 Control Register (C1M3C)
7
6
5
4
3
SFR EDh MSRDY ETI
ERI INTRQ EXTRQ
RW-0 RW-0 RW-0 RW-0 RC-0
2
MTRQ
R*-0
1
ROW/TIH
R*-0
0
DTUP
R*-0
R=Unrestricted Read, C=Clear Only, *= See description below, -n=Value after Reset
C1M3C
Bits 7-0
Operation of the bits in this register are identical to those found in the CAN 1
Message One Control Register (C1M1C;ABh). Please consult the description
of that register for more information.
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