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CY8CKIT-017 CAN/LIN Expansion Board Kit Guide, Doc. # 001-57814 Rev. *D
Hardware
Figure 4-4. CAN Circuit
4.3
LIN Physical Layer Transceiver Circuits
The two LIN physical layer transceiver circuits on the expansion board use a TJA1020 LIN
transceiver device. This device translates high-voltage LIN bus signals to and from digital CMOS
signals with standard TTL voltage levels.
Three signals are used between each LIN circuit and the PSoC controller. For the LIN1 circuit, the
three signals are LIN1_RX, LIN1_TX, and LIN1_NSLP. For the LIN2 circuit, the signals are
LIN2_RX, LIN2_TX, and LIN2_NSLP. Any data signals on the LIN bus are sent to the PSoC by the
LINx_RX signal. Any data signals driven by the PSoC on the LINx_TX signal will be driven onto the
LIN bus. The LINx_NSLP signals are used to put the LIN transceiver device in and out of sleep.
By default, there are no pull-up resistors on the LINx_TX signals. A pull-up resistor footprint is
provided (R14 on LIN1_TX and R16 on LIN2_TX) on each LINx_TX signal if you want to have a pull-
up resistor on this signal.
See the TJA1020 device datasheet for details on each of the three signals of the LIN transceiver.
4.3.1
LIN Bus Connectors
The following table shows the pinout of both of the 3-pin LIN connectors (P4 and P5) on the
expansion board.
Table 4-2. LIN Connector Pinouts
By default, pin 1 of both LIN connectors (P4 and P5) are left floating. However, if the LIN1EXTPWR
jumper (JP4) is populated, pin 1 of the LIN1 connector is connected to the VIN power rail of the DVK
and EBK. If the LIN2EXTPWR jumper (JP5) is populated, pin 1 of the LIN2 connector is connected
to the VIN power rail of the DVK and EBK. Populating either one of these jumpers is useful if you
want to power up other LIN nodes through the either of the LIN connectors, or if you want to power
up the DVK and EBK from the power supply of some other LIN node.
Warning: Take extra care when populating the LIN1EXTPWER or LIN2EXTPWR jumpers. The DVK
or EBK can be damaged if the DVK and EBK are powered by a power supply at the VIN rail and a
different power supply is connected through pin 1 of either LIN connector.
4.3.2
LIN Circuit Isolation
Both LIN circuits can be completely isolated from the rest of the CY8CKIT-001 DVK by removing
resistors R19, R23, and R25 (to isolate the LIN1 circuit) or R20, R24, and R26 (to isolate the LIN2
Pin
LIN1
LIN2
1
NC (VBAT)
NC (VBAT)
2
LIN_BUS
LIN_BUS
3
GND
GND