Texas Instruments RM48 series, Technical Reference Manual

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DCAN Control Registers
1115 SPNU503C – March 2018
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Controller Area Network (DCAN) Module
Table 23-30. CAN TX IO Control Register Field Descriptions (continued)
Bit Field Value Description
0 In CAN_TX data in.
0 The CAN_TX pin is at logic low (0).
1 The CAN_TX pin is at logic high (1).
Note: When CAN_TX pin is connected to a CAN transceiver, an external pullup resistor has to be
used to ensure that the CAN bus will not be disturbed (for example, while the DCAN module is
reset).
23.17.31 CAN RX IO Control Register (DCAN RIOC)
The CAN_RX pin of the DCAN module can be used as general-purpose IO pin if CAN function is not
needed.
NOTE: The values of the IO Control registers are writable only if Init bit of CAN Control Register is
set.
The OD, Func, and Dir bits of the CAN RX IO Control register are forced to certain values
when Init bit of CAN Control Register is reset, see bit description.
Figure 23-75. CAN RX IO Control Register (DCAN RIOC) [offset = 1E4h]
31 19 18 17 16
Reserved PU PD OD
R-0 R/W-D R/W-D R/WP-0
15 4 3 2 1 0
Reserved Func Dir Out In
R-0 R/WP-0 R/WP-0 R/WP-0 R-U
LEGEND: R/W = Read/Write; R = Read only; WP = Protected Write (protected by Init bit); D = Device-dependent; - n = value after reset;
U = Undefined
Table 23-31. CAN RX IO Control Register Field Descriptions
Bit Field Value Description
31-19 Reserved 0 These bits are always read as 0. Writes have no effect.
18 PU CAN_RX Pullup/Pulldown select. This bit is only active when CAN_RX is configured to be an input.
0 CAN_RX Pulldown is selected, when pull logic is active (PD = 0).
1 CAN_RX Pullup is selected, when pull logic is active (PD = 0).
17 PD CAN_RX pull disable. This bit is only active when CAN_RX is configured to be an input.
0 CAN_RX pull is active.
1 CAN_RX pull is disabled.
16 OD CAN_RX open drain enable. This bit is only active when CAN_RX is configured to be in GIO mode
(RIOC.Func = 0).
0 The CAN_RX pin is configured in push/pull mode.
1 The CAN_RX pin is configured in open drain mode.
Forced to 0 if Init bit of CAN control register is reset.
15-4 Reserved 0 These bits are always read as 0. Writes have no effect.
3 Func CAN_RX function. This bit changes the function of the CAN_RX pin.
0 CAN_RX pin is in GIO mode.
1 CAN_RX pin is in functional mode (as an input to receive CAN data).
Forced to 1 if Init bit of CAN control register is reset.