Contents
How do I choose a pull-up resistor?
A rule of thumb is to use a resistor that is at least 10 times smaller than the value of the input pin impedance. In bipolar logic families which operate at operating at 5 V, the typical pull-up resistor value is 1-5 kΩ. For switch and resistive sensor applications, the typical pull-up resistor value is 1-10 kΩ.
What is LIN bus voltage?
The LIN bus, and LIN transceivers, typically operate at voltages ranging from 9 V to 18 V, but some go up to 30 V, depending on the application; a typical vehicle is a 12-V battery system, but some larger vehicles go up to 24 V.
What is pull-up resistor needed for an open collector gate?
A pull-up resistor connects unused input pins (AND and NAND gates) to the dc supply voltage, (Vcc) to keep the given input HIGH. Some open-collector gates, such as the 74LS06 are capable of driving larger loads because their outputs can be connected to supplies of up to 30 volts via an external pull-up resistor.
Why pull up resistors are used?
In electronic logic circuits, a pull-up resistor or pull-down resistor is a resistor used to ensure a known state for a signal. A pull-up resistor effectively establishes an additional loop over the critical components, ensuring that the voltage is well-defined even when the switch is open.
How do you test for LIN?
An easy way to check the LIN wiring is to unplug the slave module and check the ‘at rest’ voltage of the LIN wire. The master should send out the 7 to 12 volt reference. If the wiring to the multi-function switch checks out good, replace the switch. If the input shows to be correct, check the bussed outputs.
Why do you need a pull-up resistor?
How does the pull up resistor on the LIN bus work?
Under normal LIN bus operation, this pull- up resistor provides a voltage bias on the LIN bus line to the slave nodes on the LIN network. It does not power the LIN slave nodes. Slave node power is derived from the battery input to the device, as shown in Figure 1.
What is the minimum pull up resistor for Atmel Lin?
The pull-up resistor must be reduced in size to the smallest value possible without exceeding the current limitation specification of the LIN driver. In the case of the typical Atmel LIN transceiver, the ATA6624, the recommended minimum pull-up resistor value is 220Ω.
Can a Master pull up resistor be used in two wire networking?
The 1kΩ master pull-up resistor specified in the LIN standard specification cannot be used in the two-wire configuration. The resistor is too large and, as a result, is unable to properly source the slave node load (slave node current will be discussed in further detail in the following chapter).
How is the pull up resistor of an I2C bus limited?
The maximum pullup resistance is limited by the bus capacitance (Cb) due to I2C standard rise time specifications. If the pullup resistor value is too high, the I2C line may not rise to a logical high before it is pulled low.