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3.6 Using Automatic RS-485 within Linux
A special ioctl command has been added to the Linux kernel's serial code to turn off and
on the automatic RS-485 feature. The header files needed to be included from the Linux
kernel source tree and an applications source code are linux/ts_sbc.h and linux/include/
asm/ioctls.h. These header files can be found in a Linux kernel patched with an
appropriate patch from Technologic Systems. The following snippet of code
demonstrates the use of this ioctl.
#include <linux/ts_sbc.h>
#include <linux/include/asm/ioctls.h>
<snip>
mcr = AUTO485FD
//mcr = AUTO485HD //for half duplex
ioctl (fd, TIOC_SBCS485, &mcr);
//write() and read() from fd
ioctl (fd, TIOC_SBCC485, &mcr);
//further reads() and writes() may not behave
3.7 Adding Serial Ports
If your project requires more than two serial ports, additional ports may be added via the
PC/104 expansion bus. Technologic Systems offers three different daughter boards (TS-
SER1, TS-SER2, and TS-SER4) that add 1, 2, or 4 extra COM ports respectively.
These can be configured using PC designations COM1, COM2, or higher. These will
appear in the TS-7200 PC/104 address space (0x11A0_0000 base address). For
example, a TS-SER1 daughter board can be jumper selected as COM3 which would
correspond to a PC I/O base address of 0x3E8. On the TS-7200, this COM port will
appear at the physical base address of 0x11A0_03E8.
The TS-7200 PC/104 expansion bus has IRQ5, IRQ6, and IRQ7 available for additional
serial port interrupts.
TS-7200 User's Manual Technologic Systems http://www.embeddedARM.com/
11 12/2004