On Sun, 14 Nov 1999, jsnyder wrote:
> I'm working on an application that requires the serial port to run at
> 115kbps. (This is a requirement of the device I am talking to from the
> serial port)
> The way I see it now, I will have to talk directly to the UART, while
> suspending all other processes, and then let other processes resume when I
> am done (if that is possible). Is this feasable, or is there perhaps some
> simpler method thru the OS that I can get the port to run at 115k?
You can simply open the port with B115200 or similar (grep SerialMgr.h),
so you will not have to access it directly. The serial calls so far will
generate whatever baud rates the UART is capable of, or get very close.
Why would you have to suspend anything? There aren't really any other
processes running except for interrupt handlers. And the Palm can keep up
with 115Kbaud for straight serial. And you can increase the size of the
input buffer.
> Secondly, is the real time clock a separate chip or is it a function of the
> OS? I still need to keep accurate time, regardless of what else I may be
> doing.
It is on chip and tracks the DMY HMS time and alarms. The timer ticks are
kept by the OS, but driven by a timer interrupt on chip, so it will not
lose these short of the power being off.
The baud rate and ticks imply leaving the main system clock alone - the
one running just above 16Mhz. Alter this, and you will alter the tick
frequency and baud rate (but not the RTC).
