DESK-XZU-L/Peripherals/UART
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| 2026/08/27 | DESK-XZU-L 2.2.0 release | ||
Contents
Peripheral UART[edit | edit source]
The Zynq Ultrascale second UART device (UART0) is routed through the PL and it is mapped to the ttyPS1 device
Accessing the peripheral[edit | edit source]
Linux messages at boot time[edit | edit source]
... [ 2.473625] ff000000.serial: ttyPS1 at MMIO 0xff000000 (irq = 24, base_baud = 6249999) is a xuartps [ 2.477759] ff010000.serial: ttyPS0 at MMIO 0xff010000 (irq = 25, base_baud = 6249999) is a xuartps ...
Usage with stty[edit | edit source]
N.B. UART mapping respect to ttyPSX is the following one:
UART0 (RS232) <-> ttyPS1 UART1 (Serial Port) <-> ttyPS0
root@onda:~# stty -F /dev/ttyPS1 115200 -echo root@onda:~# cat /dev/ttyPS1 & [1] 915 root@onda:~# echo "Test loopback" > /dev/ttyPS1 root@onda:~# Test loopback
Helloworld from UART0[edit | edit source]
On target we need to loopback pin 1 and 2 of PMOD A.
Here below an example on C code for initializing and using UART0 through FPGA:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
int main()
{
int fd;
char *portname = "/dev/ttyPS1";
int numchar;
char msg[] = "Hello World from DESK-XZU-L-2.2.0 (FPGA PS0 UART)!\r";
fd = open(portname, O_RDWR | O_NOCTTY | O_SYNC);
if (fd < 0)
{
printf("error %d opening %s: %s", errno, portname, strerror (errno));
exit(1);
}
numchar = write(fd, msg, strlen(msg));
exit(errno);
}
For compile it, please use the following instruction:
dvdk@vagrant:~$ wget https://mirror.dave.eu/desk-xz-l/desk-xzu-l-2.0.0/Petalinux/onda_eg_sdk.sh --2025-06-13 09:27:27-- https://mirror.dave.eu/desk-xz-l/desk-xzu-l-2.0.0/Petalinux/onda_eg_sdk.sh Resolving mirror.dave.eu (mirror.dave.eu)... 84.46.251.143 Connecting to mirror.dave.eu (mirror.dave.eu)|84.46.251.143|:443... connected. HTTP request sent, awaiting response... 200 OK Length: 963331875 (919M) [text/x-sh] Saving to: ‘onda_eg_sdk.sh’ onda_eg_sdk.sh 100%[====================================================================================================>] 918.70M 236KB/s in 27m 56s 2025-06-13 09:55:23 (561 KB/s) - ‘onda_eg_sdk.sh’ saved [963331875/963331875] dvdk@vagrant:~$ chmod 755 onda_eg_sdk.sh dvdk@vagrant:~$ ./onda_eg_sdk.sh PetaLinux SDK installer version 2024.2 ====================================== Enter target directory for SDK (default: /opt/petalinux/2024.2): You are about to install the SDK to "/opt/petalinux/2024.2". Proceed [Y/n]? Extracting SDK.......................................................................................................................................................................................................................done Setting it up...done SDK has been successfully set up and is ready to be used. Each time you wish to use the SDK in a new shell session, you need to source the environment setup script e.g. $ . /opt/petalinux/2024.2/environment-setup-cortexa72-cortexa53-xilinx-linux dvdk@vagrant:~$ source /opt/petalinux/2024.2/environment-setup-cortexa9t2hf-neon-xilinx-linux-gnueabi dvdk@vagrant:~$ vi hello_UART0.c dvdk@vagrant:~$ $CC -O hello_UART0.c -o hello_UART0 dvdk@vagrant:~$ file hello_UART0 hello_UART0: ELF 64-bit LSB pie executable, ARM aarch64, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux-aarch64.so.1, BuildID[sha1]=e8feb62d81503033073cc8c39086b20db1c154ca, for GNU/Linux 5.15.0, with debug_info, not stripped dvdk@vagrant:~$
Copy hello_UART0 on target and perform the following command:
root@onda:~# ./hello_UART0 root@onda:~# Hello World from DESK-XZ7-L-2.2.0 (FPGA PS0 UART)!
Additional information[edit | edit source]
Serial ports can be used through the standard serial programming API.
For detailed information, please refer to the Serial Programming HOWTO at Serial-Programming-HOWTO
