20
votes
Accepted
Where are the uarts on the raspberry pi 4?
The preliminary Pi4 datasheet shows there are 6 UARTs.
UART GPIO
0 14/15
1 14/15
2 0/1
3 4/5
4 8/9
5 12/13
Given that UART 0/1 are both connected to the same GPIO you can only use ...
- 71.5k
14
votes
Where are the uarts on the raspberry pi 4?
As Joan has stated only 1 of UART0/1 is accessible (UART0 /dev/ttyAMA0 is connected to Bluetooth on later model Pi).
There are additional UART on the Pi4.
Raspberry Pi4 UART is a more up to date ...
- 61k
13
votes
Pi 4 I/O interface options... and where to find them
The preliminary Raspberry Pi 4 Model B datasheet, section "5.1.1 GPIO Pin Assignments" says:
As well as being able to be used as straightforward software controlled input and output (with ...
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11
votes
Accepted
Bit waveform clarification
To me it looks like ser.write(1) has an implicit conversion to string. So your 1 becomes a "1" which is 00110001, which perfectly fits into your observation.
- 2,702
8
votes
How to get more than one uart interface
The Raspberry Pi 4 supports up to 4 UART interfaces now that need to be enabled by means of an device tree overlay. You can find how to do this and which Pins are used here for now:
https://www....
- 181
8
votes
Accepted
multiple UARTs on the 40-pin
so where was one big misunderstandings. thanks to @joan for pointing to the docs and @tlfong01 for their link to their article:
https://penzu.com/public/b94e6b30
essentially, on the raspberry 4, there ...
- 211
6
votes
How to connect SIM800 GSM ADD-ON to RaspberryPi 3
Assuming you are talking about one of these that looks like this
you should go over this to test your device.
From what I can see
This device communicates over serial port (USART) using board pins ...
- 2,446
5
votes
How to connect SIM800 GSM ADD-ON to RaspberryPi 3
I was having trouble making my SIM800 hat work with my Raspberry Pi Zero W; I thought it could be because of burnt gpios... So I tried with my Raspberry Pi 3. Same trouble.
I then found this solution ...
- 51
5
votes
Is Fingerprint Scanner TTL (GT-511C3) compatible with Raspberry Pi Zero?
This Fingerprint Scanner is compatible with the Raspberry Pi Zero. As it uses UART to interface.
Amazon.com says the fingerprint scanner uses, "Simple UART protocol (Default 9600 baud)".
Since the ...
- 173
5
votes
Accepted
Impact of using UART
The three options are:
default configuration
UART0/ttyAMA0 to Bluetooth
Mini-UART/dev/ttyS0 to GPIOs 14 and 15
pi3-disable-bt
no Bluetooth support
UART0/ttyAMA0 to GPIOs 14 and 15
pi3-miniuart-bt
...
- 1,728
5
votes
How do I use a Raspberry Pi to install OpenWrt firmware on a BT HomeHub 5a or PlusNet Hub One router
Note I am deliberately answering my own question
There are lots of detailed guides out there; this is an overview of the key points particularly with respect to using a Raspberry Pi as the host.
Take ...
- 438
4
votes
Accepted
What is the difference between the GPIO pins BCM 14 and BCM 18?
All of the GPIO pins can be configured for different purposes. At their simplest they can all act as general purpose input/output (hence the name). This means they can be set to act as an outputs, ...
- 761
4
votes
What is the difference between the GPIO pins BCM 14 and BCM 18?
All GPIO pins can be either Input or Output, and many can have alternate functions. See Pinout for details of alternatives.
Depending on the Pi model, Pins 8/10 (BCM 14/15) are usually configured as ...
- 61k
4
votes
UART interrupt in Raspberry PI with c or c++
The linux UART API (really, the POSIX termios API, but you should use the system man pages for implementation specifics; everything is mostly in man 3 termios) creates a file descriptor that can be ...
- 59.5k
4
votes
Connect sim800 to Raspberry PI (RX, TX)
The circuit as shown will not work as there is no common voltage reference between the SIM and the Pi.
You need to connect a Pi ground to either the SIM ground or to the battery ground (-ve terminal)....
- 71.5k
4
votes
Connect sim800 to Raspberry PI (RX, TX)
Just yesterday I managed to make my assembly respond. Here are my steps:
Disable Serial Console
sudo raspi-config --> Interfaces --> Serial --> No to 1st prompt; Yes for the 2nd
Use "serial0" instead ...
- 41
4
votes
Accepted
Read & Write on UART don't work
Isn't /dev/ttyAMA0 used for Bluetooth on the Raspberry Pi3?
You may need to use /dev/ttyS0 or /dev/serial1 on the Pi3 (check in /boot/overlays/README).
- 71.5k
4
votes
Accepted
Can I use the TX/RX pins and the USB ports for multiple serial devices?
You can use multiple USB serial dongles. They will appear as /dev/ttyUSBx where x will be a small number such as 0, 1, 2. You can use any serial software you want. They will all use the Linux ...
- 71.5k
4
votes
Disable UART such that it will not be on during the boot process, but only after
You can solve this by setting the bootdelay of u-boot to -2 using the u-boot console:
setenv bootdelay=-2
saveenv
Another solution is adding these lines of code to include/configs/rpi.h:
#define ...
- 141
4
votes
Accepted
UART RX stops reading data after working correctly
Check if you have disabled the login prompt on /dev/serial0. What you see may be due to two processes (your script and getty) reading from the same port.
Login prompt on serial port can be disabled ...
- 28.1k
4
votes
Impact of using UART
(See Janka's answer for the practical implications, I just wanted to clear up another aspect of the question).
so it's just a software connection.
Not exactly.
The BCM283x SoCs like many higher ...
- 6,546
4
votes
Accepted
software solution for non-blocking UART communications
This is not correct. Even single core CPUs are capable of running multiple processes giving them short time window to run and then switching to next process. Also both Python and C programs are ...
4
votes
Accepted
Multiple Rpi Serial Ports Problem
Since I cannot leave a comment, I will use the Answer form.
I had a similar task and looked at several multi-port ICs to build onto a board, I ended up using a USB hub and multiple USB to serial (RX &...
- 221
4
votes
Accepted
Simple command line to write and read data from UART (serial) loopback
The reason nothing happens is because you are sending to the UART, but not reading.
Try
cat < /dev/serial0
Most of us would use a serial monitor e.g. minicom or miniterm:
python3 -m serial....
- 61k
4
votes
Accepted
How can I disable the serial console on distributions that use U-Boot?
Here is the video where it is explained step by step how to prevent U-boot console from interrupting autoboot and sending debug messages on UART. I know links only answers are frowned upon, so here' s ...
- 66
4
votes
Accepted
Does a UART connection require shared ground?
Q: "Does a UART connection need/require a shared ground?"
A: No, it does not. UART is a communication protocol that has been successfully used in applications that prohibit the use of a ...
- 22.6k
4
votes
Accepted
UART (not the board itself) stopped working after connecting 5V to GND, can it be recovered?
If a UART GPIO is damaged that is a permanent failure and can not be fixed. In fact the damage can spread to adjacent GPIO causing them to fail and eventually the whole board may be damaged.
To check ...
- 71.5k
3
votes
Accepted
Share UART via network
I was able to find a solution based on this post: http://www.linuxquestions.org/questions/linux-networking-3/serial-over-lan-from-linux-to-windows-825334/#post4062960
Following steps are necessary.
...
- 255
3
votes
How to set non standard serial port speed
The clock speed of the serial port is 3000000Hz (3MHz).
We can UNDERclock this (as low as 1MHz), but we cannot OVERclock it (with any confidence).
So we will pick the Baud Rate one-above the speed you ...
- 61
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