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→Peripheral UART
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== Peripheral UART ==
The Zynq-7000 second UART device (UART0) is routed through the PL and it is mapped to the <code>ttyPS1</code> device.This feature is available in the [[DESK-XZ7-L/Development/Creating_and_building_the_Vivado_project#CAN0_and_UART0_routing_example_project | Vivado project example]] using the TCL scripts here below: * <code>recreate_prj_bora_BASE.tcl</code>* <code>recreate_prj_boralite_BASE.tcl</code>* <code>recreate_prj_boralite_NAND.tcl</code>* <code>recreate_prj_borax_BASE.tcl</code>
===Accessing the peripheral ===
<pre class="workstation-terminal">
...
[ 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
...
</pre>
==== Usage with stty ====
'''N.B.''' UART mapping respect to <code>ttyPSX</code> is the following one:
UART0 (RS232) <-> ttyPS1
UART1 (Serial Port) <-> ttyPS0
<pre class="workstation-terminal">
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
</pre>
==== Helloworld from UART0 ====
On target we need to loopback pin <code>6</code> and <code>7</code> of <code>PMOD A</code>.
Here below an example on C code for initializing and using UART0 through FPGA:
<pre class="c">
#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);
}
</pre>
For compile it, please use the following instruction:
<pre class="workstation-terminal">
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
</pre>
Copy <code>hello_UART0</code> on target and perform the following command:
<pre class="workstation-terminal">
root@bora:~# chmod u+x hello_UART0
root@bora:~# ./hello_UART0
Hello World from BELK (FPGA PS0 UART)!
</pre>