On Wednesday 06 February 2002 07:19, Jeff wrote: > On Tuesday 05 February 2002 09:27 pm, friend Hsu wrote: > > Hi, how are you, > > I want to add some COM port to my StrongARM platform > > in Linux. The chip that i will use is 16C550. Is there > > any limitation of the amount of COM port that can be > > added? > > Thank you mery much. > > At some point you'll run out of device minor numbers, but probably not > before you've run out of interrupts and bandwidth to service all of them, > so as usual, the answer is: *it depends*. My SA1110 design has no trouble > keeping up with 4 16C550's plus a couple of its own internal serial ports, > all at 115,200 bps. A few more ports probably would be OK. Some tweaks to > the serial driver would be in order for more than 4 as well. For large > numbers of ports (> 8) it's probably time to start thinking of a dedicated > coprocessor...
You could also do some dark magic with adding RS232 chips that are connected to your processor via an I2C bus. You would still have the same problem wiith device number limitation, but you could have all the extra serial ports serviced by the I2C interrupt. I don't know of any I2C/RS232 drivers at the moment, but we (my company) will probably be putting one out there at some point. (please don't mail me about one - i don't have one) cheers, cam _______________________________________________ http://lists.arm.linux.org.uk/mailman/listinfo/linux-arm http://www.arm.linux.org.uk/armlinux/mailinglists.php Please visit the above addresses for information on this list.
