How to use jumper caps in circuits

xxhhzz

How to use jumper caps in circuits [Copy link]

 

Now I have a serial port (1) and want to use an external jumper cap to select which part to connect to (2) or (3). How should I design this part in the circuit? Can I use 3P pins? ? ? ?

heningbo

OK

tiankai001

Use two 3P pin headers, one for RX selection and one for TX selection

xxhhzz

tiankai001 posted on 2019-1-17 16:24 Use two 3P pin headers, one for RX selection and one for TX selection

Two 3P pin headers, I don't quite understand

xxhhzz

tiankai001 posted on 2019-1-17 16:24 Use two 3P pin headers, one for RX selection and one for TX selection

Can you give a rough drawing?

xxhhzz

tiankai001 posted on 2019-1-17 16:24 Use two 3P pin headers, one for RX selection and one for TX selection

Is this how to select?

chunyang

The most intuitive way is to use a 2*4 8-pin pin header. When wiring, follow the direction of the original poster's diagram. The 4 pins on the left are connected in parallel, and the right side corresponds to two paths. Use two jumpers to select. Plug in the upper two sets of pins to connect to the MCU, and plug in the lower two sets of pins to connect to the USB, and indicate it with silk-screen characters next to it.

chunyang

Another way is to use a 2*3 6PIN pin header. When wiring, the two middle pins are connected to the transceiver on the left side of the original poster's picture, and the two sides correspond to the MCU and USB respectively. Also use two sets of jumper caps to operate.

chunyang

Which method is appropriate needs to consider the position, size and density of components on the PCB. The principle is to facilitate direct manual operation and have space to indicate silk screen characters.

chunyang

xxhhzz Posted on 2019-1-17 17:29 Is this the way to choose?

There is no need to consider GND. If the floating end needs to have a fixed level, use an external pull-up resistor, but grounding will cause problems, which will conflict with the start bit of the serial port.

曹伟1993

What does it mean when you choose to circle the first one? Isn't it enough to leave two pins for RX and TX output on the board?

arm8686

littleshrimp

arm8686 posted on 2019-1-17 20:21

This method is more common

LeoMe

Learn more about CD4052. It can be controlled by program or DIP switch. Why do we need pin headers? Pin headers are not much cheaper.

tiankai001

xxhhzz

chunyang posted on 2019-1-17 17:41 Another way is to use a 2*3 6PIN pin header. When wiring, the two middle pins are connected to the transceiver on the left side of the OP's picture. The two sides correspond to the MCU and USB respectively. Also use two...

Is that it?

tiankai001

LeoMe posted on 2019-1-18 08:49 Learn more about CD4052. It can be controlled by program or DIP switch. Why must it have pin header? Pin header is not much cheaper

DIP switch is a good choice

tiankai001

xxhhzz posted on 2019-1-18 09:00 Is that it?

Note that the Rx of the serial port should be connected to the Tx of the microcontroller.

chunyang

The 15th floor is a typical 6-pin connection, and the 17th floor is equivalent to the 8-pin connection. However, it is not recommended to use two independent 3-pins, because that requires two markings, which is easy to be overlooked, unless the PCB is very empty. The 8-pin connection is replaced by a dip switch. Unless it is due to height restrictions, the surface-mounted micro-dip switch, which is the kind that needs to be operated with tweezers, is not recommended (referring to ordinary dip switches). Because a dip switch must be given on the PCB, incorrect settings due to "hand tidal" may cause level competition. Good design should not only consider the correctness of the electrical principle, but also consider processability and ease of use.

zhuyebb

I strongly support the OP ing...