DESK-XZ7-L/Peripherals/UART
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| DESK-XZ7-L-1.0.1 release | |||
| 2024/06/12 | DESK-XZ7-L-1.1.0 release | ||
Contents
Peripheral UART[edit | edit source]
The Zynq-7000 second UART device (UART0) is routed through the PL and it is mapped to the ttyPS1 device. This feature is available in the Vivado project example using the TCL scripts here below:
recreate_prj_bora_BASE.tclrecreate_prj_bora_ETH1.tclrecreate_prj_boralite_BASE.tclrecreate_prj_boralite_ETH1.tclrecreate_prj_boralite_NAND.tclrecreate_prj_borax_BASE.tclrecreate_prj_borax_ETH1.tcl
Accessing the peripheral[edit | edit source]
Linux messages at boot time[edit | edit source]
... [ 0.198315] e0000000.serial: ttyPS1 at MMIO 0xe0000000 (irq = 34, base_baud = 3125000) is a xuartps [ 0.207202] e0001000.serial: ttyPS0 at MMIO 0xe0001000 (irq = 35, base_baud = 3125000) 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@bora:~# stty -F /dev/ttyPS1 115200 -echo root@bora:~# cat /dev/ttyPS1 & [1] 297 root@bora:~# echo "Test loopback" > /dev/ttyPS1 root@bora:~# Test loopback
Helloworld from UART0[edit | edit source]
On target we need to loopback pin 6 and 7 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 <termios.h>
int set_interface_attribs (int fd, int speed, int parity)
{
struct termios tty;
memset (&tty, 0, sizeof tty);
if (tcgetattr (fd, &tty) != 0)
{
printf("error %d from tcgetattr", errno);
return -1;
}
cfsetospeed (&tty, speed);
cfsetispeed (&tty, speed);
tty.c_cflag = (tty.c_cflag & ~CSIZE) | CS8; // 8-bit chars
// disable IGNBRK for mismatched speed tests; otherwise receive break
// as \000 chars
tty.c_iflag &= ~IGNBRK; // disable break processing
tty.c_lflag = 0; // no signaling chars, no echo,
// no canonical processing
tty.c_oflag = 0; // no remapping, no delays
tty.c_cc[VMIN] = 0; // read doesn't block
tty.c_cc[VTIME] = 5; // 0.5 seconds read timeout
tty.c_iflag &= ~(IXON | IXOFF | IXANY); // shut off xon/xoff ctrl
tty.c_cflag |= (CLOCAL | CREAD);// ignore modem controls,
// enable reading
tty.c_cflag &= ~(PARENB | PARODD); // shut off parity
tty.c_cflag |= parity;
tty.c_cflag &= ~CSTOPB;
tty.c_cflag &= ~CRTSCTS;
if (tcsetattr (fd, TCSANOW, &tty) != 0)
{
printf("error %d from tcsetattr", errno);
return -1;
}
return 0;
}
int main()
{
int fd;
char *portname = "/dev/ttyPS1";
char msg[] = "Hello World from BELK (FPGA PS0 UART)!\n\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);
}
printf("%s", msg);
set_interface_attribs (fd, B115200, 0); // set speed to 115,200 bps, 8n1 (no parity)
write(fd, msg, strlen(msg));
exit(0);
}
For compile it, please use the following instruction:
dvdk@vagrant:~$ wget https://mirror.dave.eu/desk-xz-l/desk-xz7-l-1.0.1/desk-xz7-l-1.0.1_bora_sdk.sh --2024-01-26 11:57:04-- https://mirror.dave.eu/desk-xz-l/desk-xz7-l-1.0.1/desk-xz7-l-1.0.1_bora_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: 998591008 (952M) [text/x-sh] Saving to: ‘desk-xz7-l-1.0.1_bora_sdk.sh’ desk-xz7-l-1.0.1_bora_sdk.sh 100%[====================================================================================================>] 952.33M 10.8MB/s in 1m 40s 2024-01-26 11:58:43 (9.57 MB/s) - ‘desk-xz7-l-1.0.1_bora_sdk.sh’ saved [998591008/998591008] dvdk@vagrant:~$ chmod 755 desk-xz7-l-1.0.1_bora_sdk.sh dvdk@vagrant:~$ ./desk-xz7-l-1.0.1_bora_sdk.sh PetaLinux SDK installer version 2021.2 ====================================== Enter target directory for SDK (default: /opt/petalinux/2021.2): You are about to install the SDK to "/opt/petalinux/2021.2". Proceed [Y/n]? y 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/2021.2/environment-setup-cortexa9t2hf-neon-xilinx-linux-gnueabi dvdk@vagrant:~$ source /opt/petalinux/2021.2/environment-setup-cortexa9t2hf-neon-xilinx-linux-gnueabi dvdk@vagrant:~$ vi hello_UART0.c dvdk@vagrant:~$ $CC -O hello_UART0.c -o hello_UART0
Copy hello_UART0 on target and perform the following command:
root@bora:~# chmod u+x hello_UART0 root@bora:~# ./hello_UART0 Hello World from BELK (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
