Since this is the only forum where I can put some questions, I'm really putting all my questions here..
So I'm using the Panel Card EVB board and I know that the ARM (AT91SAM9162) has 4 Serial ports available. (Debug, 0, 1 and 2). But only two of them are available on the development board, that are the debug and 1. Well at least, that's what I can figure out looking at the schematics. Serial port 0 and 2 are wired to the X13, X10, X18 and X19 labeled as Key's.
Now I have some questions:
- First of all, Linux is only recognizing two serial ports ttyS0 (debug) and ttyS2. Is it possible, and how, that I can use all the serial ports (of course I have to add RS-232 connectors)? I probably have to change something in the boot-process of the kernel that it will recognize them all.
- Second question is, can I just add a RS-232 connector to the X13 field, to the rights pins of course) or is there some jumper that I have to change so that the wires will be connected with that field?
Thanks
Re: Serial Ports
To enable the other two UARTs, you have to edit the file arch/arm/mach-at91/board-panelcard.c in the Linux source tree. The uart configuration is at the beginning of the file. Replace -1 in the tty_map member of panelcard_uart_config with the corresponding UART values, e.g. ".tty_map = { 3, 0, 1, 2 }". After that you should not use the matrix keyboard driver, because the keyboard pins are multiplexed with the UART and it will therefore configure the pins back to GPIO mode.
To connect an RS232 cable you should not directly add a RS232 connector to X13. As the pins don't have RS232 levels, you must use a RS232 driver/receiver like IC11 on the EVB. But the UART pins are all connected, no jumpers are needed.