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Why pull-up resistor is used in 8051?
To ensure the values of an I/P is always in a known state, pull up and pull-down resistors are used. The main function of pull-up and pull-down resistors is that the pull up resistor pulls the signal to high state unless it is driven low; and, a pull-down resistor pulls the signal to low state unless it is driven high.
What are pull-up pull-down resistors used for?
In electronic logic circuits, a pull-up resistor or pull-down resistor is a resistor used to ensure a known state for a signal. It is typically used in combination with components such as switches and transistors, which physically interrupt the connection of subsequent components to ground or to VCC.
Why does Port 0 need pull up resistors?
An external pull-up resistor is needed when Port 0 is defined as an output port. Port 0 of the 8051 has two main functions: To be used as a simple input-output port and to access external memory in conjunction with Port 2.
Can a UART pull up TX and RX pins?
When not using RX and TX pins of PIC16F15345, to avoid floating pin, should I use a pull-up resistor to pull the pins up to logical High? I plan to use the UART (by connecting to the MP2221A eval board) to set the GPIOs and would like to keep the GPIO outputs as it is for a long time.
Why do I need a pull up resistor on my line driver?
This can lead to noise causing rubbish to be transmitted by the RS232 line driver. Some line driver ICs have internal pull-up resistors on their TTL/LVTTL-side input pins to prevent this and produce an RS232 idle state. Otherwise, a pull-up resistor can be added.
Do you need a pull up resistor for a PIC TX?
The PIC TX has push pull output. You do not need any pull up/down resistor in this pin. There will be no error if you add some weak pullup-down resistor in this pin. In the RX pin you could use pullup/down depending on the driver you use (eg 8051 has internal pull up so you don’t need to do anything, but for some drivers it may be nessecary).
Why do I need a 10K pull up resistor?
10k pull up resistor to controller uart lines 1 1.It will slightly prolong the signal’s fall time. 2 2.It will increase power consumption when a transmittion takes place. More