Difference between revisions of "How to use UARTs"
From IGEP - ISEE Wiki
| Line 14: | Line 14: | ||
=== Configure IGEP === | === Configure IGEP === | ||
| − | To test UARTs we use UART0 (dev/ttyS0) and UART3 (dev/ttyS2) via J960 connector. | + | To test UARTs we use UART0 (dev/ttyS0) and UART3 (dev/ttyS2) via J960 connector using RS232 standard. |
| − | NOTE: Make sure that you installed open SSH server. If you don't have it go [[ | + | NOTE: Make sure that you installed open SSH server. If you don't have it go [[How to forge a local file system server with IGEP0020 board#Installing_Open_SSH_Server|here]]. |
| − | By default, UART0 is used by RS485 driver, we need to disable RS485 support, | + | By default, UART0 is used by RS485 driver, we need to disable RS485 support, edit igep.ini file: <br> |
<pre>board.ei485= yes | <pre>board.ei485= yes | ||
</pre> | </pre> | ||
| − | Maybe you don't | + | Maybe you don't found this line, replaced by or type this:<br> |
<pre>board.ei485= no | <pre>board.ei485= no | ||
</pre> | </pre> | ||
| − | By default, UART3 is used by Kernel serial console, we need to disable it, go to igep.ini file | + | By default, UART3 is used by Kernel serial console, we need to disable it, go to igep.ini file, comment next line: <br> |
<pre>console=ttyS2,115200n8</pre> | <pre>console=ttyS2,115200n8</pre> | ||
Revision as of 12:08, 19 January 2012
Contents
Overview
This How-To is meant to be a starting point for people to learn use UART for IGEP v2 devices as quickly and easily as possible. In this how-to, we use a program (upload source code), executed twice, at the same time inside the same IGEP. Its function is get a number via UART, increase it and send result to other UART, the result will be a infinite loop between 2 UARTs. This program was testedin Linaro Headless with Kernel 2.6.35.y.
More information about UART.
Note: This program have a debug option using GPIOs to debug via oscilloscope, this option is useful to learnt about the Kernel latencies and IRQ. Debug has set to "write" and "select" functions.
Feedback and Contributing
At any point, if you see a mistake you can contribute to this How-To.
Preparing IGEP
Configure IGEP
To test UARTs we use UART0 (dev/ttyS0) and UART3 (dev/ttyS2) via J960 connector using RS232 standard.
NOTE: Make sure that you installed open SSH server. If you don't have it go here.
By default, UART0 is used by RS485 driver, we need to disable RS485 support, edit igep.ini file:
board.ei485= yes
Maybe you don't found this line, replaced by or type this:
board.ei485= no
By default, UART3 is used by Kernel serial console, we need to disable it, go to igep.ini file, comment next line:
console=ttyS2,115200n8
Check UARTs devices
Wire connectors
Compile and run program
Testing UART
Under Construction
