Verdin Carrier Board Design Guide
Preliminary
– Subject to Change
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2.13
CAN
The controller area network (CAN) bus is a multi-master serial bus standard. It was first introduced
for the automotive sector and soon became widely adopted in the industrial sector. Different
versions of CAN specifications are available. Make sure that the corresponding Verdin module
complies with the required version. Some Verdin modules support CAN FD for up to 5 times higher
data rates and larger message sizes (compared to “regular” CAN).
2.13.1
CAN Signals
Verdin
Pin
Verdin
Signal Name
I/O
Type
Power
Rail
Description
20
CAN_1_TX
O
CMOS
1.8V
CAN port 1 transmit pin
22
CAN_1_RX
I
CMOS
1.8V
CAN port 1 receive pin
24
CAN_2_TX
O
CMOS
1.8V
CAN port 2 transmit pin
26
CAN_2_RX
I
CMOS
1.8V
CAN port 2 receive pin
Table 28: CAN Signals
2.13.2
Reference Schematics
The CAN interface requires a transceiver on the carrier board. Often, the CAN interface needs to
be galvanically isolated from the Verdin computer module. There are transceivers with integrated
signal isolation available (for example the TI ISO1042BDWR). An example for a CAN FD
transceiver without integrated isolation is the Microchip MCP2558FDT. There are different types of
connectors used for the CAN interface. The reference schematic below uses single-row pin header
as connector. Since this is not an official standard, some devices might have a different connector
or pin-out.
Figure 42: CAN Reference Schematic
2.13.3
Unused CAN Interface Signal Termination
According to the Verdin standard, the CAN interface signals do not need to be GPIO capable. It
depends on the module whether the CAN interface signal pins can be used for other purposes if
the CAN interface is not in use. Some Verdin modules provide the CAN interface by using a
dedicated controller. It is recommended to tie the CAN RX signals to ground or 1.8V if the interface
is not used. This can help in reducing the power consumption of modules with stand-alone CAN
controller.
NTE0505MC-R
-V_IN
1
1
0
-V_OUT
7
5
+V_IN
3
+V_OUT
8
1
2
1
4
IC5
GND
Isolated DC/DC Converter
R6
100R
CAN_1_L
CAN_1_H
+V5_CAN_1_ISO
CAN FD
56R
R7
56R
R8
4.7nF
16V
C3
D1, D2 alternative component:
Diodes Inc., DESD2CAN2SOQ-7
VDD1
1
GND1
2
RXD
5
NC
4
TXD
3
NC
6
NC
7
GND1
8
GND2
9
GND2
10
CANL
12
CANH
13
VDD2
16
GND2
15
IS
O
L
A
T
IO
N
NC
14
VDD2
11
IC1
ISO1042BDWR
GND_CAN_1_ISO
GND
GND_CAN_1_ISO GND_CAN_1_ISO
+V5_CAN_1_ISO
GND_CAN_1_ISO
CAN_1_TX
CAN_1_RX
+V1.8_CAN_1
+V5_CAN_1
826936-5
1
2
3
4
5
X59
PESD2IVN24-T
1
2
3
D1
100nF
16V
C11
100nF
16V
C1
100nF
16V
C2
+V1.8_CAN_1
CAN_1_TX
20
CAN_1_RX
22
CAN_2_TX
24
CAN_2_RX
26
X1O
2309409-2
4.7uF
10V
C13
GND_CAN_1_ISO
+V5_CAN_1_ISO
4.7uF
10V
C12
22R
RA16D
22R
RA13A
R4
10K
SODIMM_20_M
SODIMM_22_M
100nF
16V
C302
GND
