Xuartctl: Difference between revisions
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xuartctl is a userspace driver utility to manage the UARTs that go through the FPGA. | xuartctl is a userspace driver utility to manage the UARTs that go through the FPGA. | ||
= Overview = | |||
XUART serial ports are also implemented entirely from userspace. The 8 serial ports have a single shared 4kByte receive FIFO which makes real time interrupt latency response less of a concern and in actual implementation, the serial ports are simply polled at 100Hz and don't even use an IRQ. Even with all 8 ports running at 230400 baud, it is not possible to overflow the receive FIFO in 1/100th of a second. The "xuartctl --server" daemon is started by default in the INITRD linuxrc file which sets up listening TCP/IP ports for all 8 XUART channels on ports 7350-7357. An application may simply connect to these ports via localhost (or via the network) and use the serial ports as if they were network services. | XUART serial ports are also implemented entirely from userspace. The 8 serial ports have a single shared 4kByte receive FIFO which makes real time interrupt latency response less of a concern and in actual implementation, the serial ports are simply polled at 100Hz and don't even use an IRQ. Even with all 8 ports running at 230400 baud, it is not possible to overflow the receive FIFO in 1/100th of a second. The "xuartctl --server" daemon is started by default in the INITRD linuxrc file which sets up listening TCP/IP ports for all 8 XUART channels on ports 7350-7357. An application may simply connect to these ports via localhost (or via the network) and use the serial ports as if they were network services. | ||
== | = Usage = | ||
The xuartctl utility is split into 2 parts. The first part is the main server. This server must run on the board and provides the communication between the FPGA and the TCP ports. This can be created by running: | |||
<source lang=bash> | |||
xuartctl --server | |||
</source> | |||
=== Usage | You can also specify the speed and mode arguments to make them the default for the port servers. The port servers are created by simply specifying a port after the main server has been started: | ||
< | <source lang=bash> | ||
xuartctl --server --port=0 --speed=115200 | |||
</source> | |||
== Usage == | |||
<source lang=bash> | |||
xuartctl --help | xuartctl --help | ||
Usage: xuartctl [OPTION] ... | Usage: xuartctl [OPTION] ... | ||
| Line 35: | Line 46: | ||
-t, --test Run loopback and latency test | -t, --test Run loopback and latency test | ||
-h, --help This help | -h, --help This help | ||
</source> | |||
== Supported Modes == | |||
{| class="wikitable" | {| class="wikitable" | ||
|- | |- | ||
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|} | |} | ||
= Examples = | |||
== Change the default mode and baud rate for all ports == | |||
The default mode is "8N1" and default baud rate is 115200-- should the default need to be changed, modifying the linuxrc line that invokes the XUART server can be changed from: | The default mode is "8N1" and default baud rate is 115200-- should the default need to be changed, modifying the linuxrc line that invokes the XUART server can be changed from: | ||
< | <source lang=bash> | ||
xuartctl --server | xuartctl --server | ||
</ | </source> | ||
to | to | ||
< | <source lang=bash> | ||
xuartctl --server --speed=9600 --mode=7e1 | xuartctl --server --speed=9600 --mode=7e1 | ||
</ | </source> | ||
== Configure baud rate for specific port == | |||
< | <source lang=bash> | ||
xuartctl --port 0 --speed 115200 | xuartctl --port 0 --speed 115200 | ||
</ | </source> | ||
== Configure xuarts on startup == | |||
Edit your /etc/rc.local file and add in these lines before exit: | Edit your /etc/rc.local file and add in these lines before exit: | ||
< | <source lang=bash> | ||
eval $(xuartctl --port 0 --speed 9600 2>&1); ln -s $ttyname /dev/ttyxuart0 | eval $(xuartctl --port 0 --speed 9600 2>&1); ln -s $ttyname /dev/ttyxuart0 | ||
eval $(xuartctl --port 1 --speed 115200 2>&1); ln -s $ttyname /dev/ttyxuart1 | eval $(xuartctl --port 1 --speed 115200 2>&1); ln -s $ttyname /dev/ttyxuart1 | ||
eval $(xuartctl --port 2 --speed 38400 2>&1); ln -s $ttyname /dev/ttyxuart2 | eval $(xuartctl --port 2 --speed 38400 2>&1); ln -s $ttyname /dev/ttyxuart2 | ||
</ | </source> | ||
== Create a local xuart port server running on a remote xuartctl main server == | |||
If the xuartctl --server is running remotely on 192.168.0.50, you could run this from any remote system: | If the xuartctl --server is running remotely on 192.168.0.50, you could run this from any remote system: | ||
< | <source lang=bash> | ||
xuartctl --port=192.168.0.50:7350 --speed=9600 | xuartctl --port=192.168.0.50:7350 --speed=9600 | ||
</ | </source> | ||
= FAQ = | |||
== How do I kill the old xuart process controlling one port? == | |||
When you run xuartctl on a port that is already running, it will replace that instance without affecting the other configured ports. | When you run xuartctl on a port that is already running, it will replace that instance without affecting the other configured ports. | ||
== xuartctl works in the booted environment, but not in my startup scripts == | |||
Make sure the main server is started when you try to start a port server. If you add your scripts in /etc/rc.local or your fastboot linuxrc, you should be fine. However if it doesn't start you can create the main server instance with: | Make sure the main server is started when you try to start a port server. If you add your scripts in /etc/rc.local or your fastboot linuxrc, you should be fine. However if it doesn't start you can create the main server instance with: | ||
< | <source lang=bash> | ||
xuartctl --server | xuartctl --server | ||
</ | </source> | ||
== When I brought up my first port it appeared as /dev/pts/1, but normally shows up as /dev/pts/0 == | |||
The psuedo terminal devices will show up in order they were brought up, and other devices can claim them as xuartctl does. If you want this consistancy, it is usually best to link the files to the output of xuartctl's ttyname. | The psuedo terminal devices will show up in order they were brought up, and other devices can claim them as xuartctl does. If you want this consistancy, it is usually best to link the files to the output of xuartctl's ttyname. | ||
Revision as of 15:58, 16 June 2011
 |
xuartctl is a userspace driver utility to manage the UARTs that go through the FPGA.
Overview
XUART serial ports are also implemented entirely from userspace. The 8 serial ports have a single shared 4kByte receive FIFO which makes real time interrupt latency response less of a concern and in actual implementation, the serial ports are simply polled at 100Hz and don't even use an IRQ. Even with all 8 ports running at 230400 baud, it is not possible to overflow the receive FIFO in 1/100th of a second. The "xuartctl --server" daemon is started by default in the INITRD linuxrc file which sets up listening TCP/IP ports for all 8 XUART channels on ports 7350-7357. An application may simply connect to these ports via localhost (or via the network) and use the serial ports as if they were network services.
Usage
The xuartctl utility is split into 2 parts. The first part is the main server. This server must run on the board and provides the communication between the FPGA and the TCP ports. This can be created by running:
xuartctl --server
You can also specify the speed and mode arguments to make them the default for the port servers. The port servers are created by simply specifying a port after the main server has been started:
xuartctl --server --port=0 --speed=115200
Usage
xuartctl --help
Usage: xuartctl [OPTION] ...
xuartctl --port=PORT [OPTION] ... -- [COMMAND] [ARGS]
Technologic Systems XUART core userspace driver utility.
Example: xuartctl --server
xuartctl --port=192.168.0.50:7350 --speed=9600 -- /bin/sh -i
xuartctl --port=0 --test
-i, --irq=N Use IRQ N as XUART IRQ (32)
-r, --regstart=ADD Use ADD address as regstart (0x600ff100)
-m, --memstart=ADD Use ADD address as memstart (0x60000000)
-s, --speed=BAUD Use BAUD as default baudrate (115200)
-o, --mode=MODE Use MODE as default mode (8n1)
-d, --server Daemonize and run as server
-p, --port=PORT Connect to local or remote XUART port
-t, --test Run loopback and latency test
-h, --help This help
Supported Modes
| Mode | Notes |
|---|---|
| 8n1 | (default mode) |
| 8n2 | |
| dmx | baudrate argument is ignored, uses 250 kbaud |
| 8e1 | |
| 8o1 | |
| 8e2 | |
| 8o2 | |
| 7n1 | |
| 7n2 | |
| 7e1 | |
| 7o1 | |
| 7e2 | |
| 7o2 | |
| 9n1 | The pseudo-tty is incompatible with this mode. You must use TCP. |
Examples
Change the default mode and baud rate for all ports
The default mode is "8N1" and default baud rate is 115200-- should the default need to be changed, modifying the linuxrc line that invokes the XUART server can be changed from:
xuartctl --server
to
xuartctl --server --speed=9600 --mode=7e1
Configure baud rate for specific port
xuartctl --port 0 --speed 115200
Configure xuarts on startup
Edit your /etc/rc.local file and add in these lines before exit:
eval $(xuartctl --port 0 --speed 9600 2>&1); ln -s $ttyname /dev/ttyxuart0
eval $(xuartctl --port 1 --speed 115200 2>&1); ln -s $ttyname /dev/ttyxuart1
eval $(xuartctl --port 2 --speed 38400 2>&1); ln -s $ttyname /dev/ttyxuart2
Create a local xuart port server running on a remote xuartctl main server
If the xuartctl --server is running remotely on 192.168.0.50, you could run this from any remote system:
xuartctl --port=192.168.0.50:7350 --speed=9600
FAQ
How do I kill the old xuart process controlling one port?
When you run xuartctl on a port that is already running, it will replace that instance without affecting the other configured ports.
xuartctl works in the booted environment, but not in my startup scripts
Make sure the main server is started when you try to start a port server. If you add your scripts in /etc/rc.local or your fastboot linuxrc, you should be fine. However if it doesn't start you can create the main server instance with:
xuartctl --server
When I brought up my first port it appeared as /dev/pts/1, but normally shows up as /dev/pts/0
The psuedo terminal devices will show up in order they were brought up, and other devices can claim them as xuartctl does. If you want this consistancy, it is usually best to link the files to the output of xuartctl's ttyname.