Pull-up and pull-down resistors

xbxdbd

Pull-up and pull-down resistors [Copy link]

 

Can someone explain to me whether a pull-up resistor or a pull-down resistor should be placed in the magnetic control circuit? Is it to improve the driving capability?

maychang

In your diagram, pull-down resistors R10~R12 have been added to LIMIT1~LIMIT3.

maychang

[It is to improve driving ability]

The load of the microcontroller is outside the P2 [single-row pin]. If you don't know what the load is, how can you talk about [should I put in a pull-up resistor or a pull-down resistor]?

xbxdbd

maychang posted on 2023-9-14 10:03 [It is to improve the driving capability] The load of the microcontroller is outside the P2 [single-row pin]. I don’t know what the load is, so how can I talk about [it should be put in the pull-up circuit...

The load is a Hall switch, which is used to magnetically sense the light intensity of the objective lens. This P2 is used to connect the magnetic control board. The magnetic control board contains 3 Hall switches and a single-row pin to connect the P2 interface of the motherboard.

maychang

xbxdbd posted on 2023-9-14 10:35 The load is a Hall switch, which is used to magnetically control the light intensity of the objective lens. This P2 is used to connect the magnetic control board, which contains 3 Hall switches and a...

[The load is a Hall switch, which is used to magnetically control the light intensity of the objective lens. This P2 is used to connect the magnetic control board. The magnetic control board contains 3 Hall switches and a single-row pin to connect to the P2 interface of the motherboard]

After all this talk, I only know that the 3/4/5 pins of the P2 socket are connected to one end of the three Hall switches, but who knows where the other end of your [Hall switch] is connected to? Is it connected to the positive terminal of the power supply or the ground?

maychang

xbxdbd posted on 2023-9-14 10:35 The load is a Hall switch, which is used to magnetically control the light intensity of the objective lens. This P2 is used to connect the magnetic control board, which contains 3 Hall switches and a...

[The load is a Hall switch, which is used to magnetically control the light intensity of the objective lens. This P2 is used to connect the magnetic control board. The magnetic control board contains 3 Hall switches and a single-row pin to connect to the P2 interface of the motherboard]

Also, is the Hall switch an input or output for the microcontroller? It seems that the output signal of the Hall switch is the input signal of the microcontroller.

xbxdbd

This is our magnetron circuit board

xbxdbd

maychang posted on 2023-9-14 10:56 [The load is a Hall switch, which is used to magnetically control the light intensity of the objective lens. This P2 is used to connect the magnetic control board, and the magnetic control board is equipped with 3 Hall switches and...

The Hall sensor is an analog signal input device. The voltage signal it outputs is converted into a digital signal by an AD converter and then input into the MCU.

xbxdbd

maychang posted on 2023-9-14 10:56 [The load is a Hall switch, which is used to magnetically control the light intensity of the objective lens. This P2 is used to connect the magnetic control board, and the magnetic control board is equipped with 3 Hall switches and...

The internal structure of the Hall switch is an open collector structure, so a pull-up resistor should be added, right?

maychang

xbxdbd posted on 2023-9-14 11:07 The Hall sensor is an analog signal input device. The voltage signal it outputs is converted into a digital signal by an AD converter and then input into the MCU

[The Hall sensor is an analog signal input device. The voltage signal it outputs is converted into a digital signal by an AD converter and then input into the MCU]

According to the diagram on the 7th floor, one end of your Hall sensor is connected to a 5V power supply, one end is grounded, and the output ends are M1, M2, and M3. The output of the Hall sensor is directly connected to the three pins of the microcontroller, and is grounded by three resistors R10, R11, and R12.

As for [improving driving capability], it is obviously to increase the driving capability of the Hall sensor. This should refer to the Hall sensor manual and is not up to the circuit designer.

maychang

xbxdbd posted on 2023-9-14 11:41 The internal structure of the Hall switch is an open collector structure, so should a pull-up resistor be added?

The first post said it was a [Hall switch], which means a switch, and its output is a digital signal. The 8th post later said [Hall sensor], which is an [analog signal input device, and [the output voltage signal is converted into a digital signal by an AD converter]. What exactly is it? Again, refer to the manual.

maychang

xbxdbd posted on 2023-9-14 11:41 The internal structure of the Hall switch is an open collector structure, so should a pull-up resistor be added?

[Hall switch] Check the manual to see if it is an open collector structure. Even if it is an open collector structure, the connection method of the external resistor is exactly the opposite for the output stage of NPN tube and the output stage of PNP tube.

xbxdbd

maychang posted on 2023-9-14 11:48 [The Hall sensor is an analog signal input device. The voltage signal it outputs is converted into a digital signal by an AD converter and then input into the MCU] According to the 7th floor diagram...

I am just wondering whether R10, R11, and R12 should be connected to the power supply or the ground. Our original design was to connect to the power supply VCC.

xbxdbd

maychang posted on 2023-9-14 11:54 [Hall switch] Whether it is an open collector structure, see the instructions. Even if it is an open collector structure, the output stage is an NPN tube and the output stage is a PNP tube, the external...

I get it, thank

maychang

xbxdbd posted on 2023-9-14 11:55 I am just wondering whether R10, R11, and R12 should be connected to the power supply or the ground. Our original design was to connect to the power supply VCC

[I am just wondering whether R10, R11, and R12 should be connected to the power supply or the ground. Our original design is to connect to the power supply VCC]

In most cases, these three resistors should be connected to Vcc, because the open-collector output stage is mostly an NPN tube.

However, the instructions should still prevail.

led2015

Place a pull-up resistor to increase the drive capability. This resistor is connected to the input port (such as the output of a switch or sensor) on one end and to the positive power supply or high-level power supply point on the other end.

器铭123

To increase the drive capability, put a pull-up resistor