Sounds good.
Thanks
-Joe
Michael Tasche wrote:
Hi Joe,
as you know, there are many PCI or CPCI serial boards with 16550.
Normally this boards defaults to the PC compatible frequency, to
simplify the use of the boards in PC’s.
If a poor customer, reading the QNX docu and starting the driver for
such a board on a PPC machine, he gets into trouble, because he cannot
know, that there is a different default frequency for the PPC-variant.
I thought, having one default frequency for all CPU variants would
make things simpler.
Ok, if you do not like that, please correct the official documentation.
At the moment, you will find this in the docu:
“-c clock[/divisor]
Define a custom clock rate, in hertz, and divisor for the serial port.
The default (-c 1843200/16) is suitable for compatible PC serial ports.”
-Michael
Joe Mammone schrieb:
The default values are based on the hardware the driver was developed
for. This driver is for 16550 compatible UARTs (not necessarily
PCs)…the x86 variant defaults to 1843200/16 because the most
common hardware with this UART is a PC, in the PPC case the hardware
that was available used a clock setting of 7372800/16 and so it was
chosen as the default for PPC.
These UART come attached to many different pieces of hardware with a
wide variety of configuration. The default settings are simply
convenience…in most custom scenarios you will need to specify
options to configure the driver to your specific needs. As Michael
mentioned, if passing arguments to a driver is not something you like
to do, then you can download the source for free (contained in the
Char DDK) and tailor the driver as you see fit.
-Joe
Michael Tasche wrote:
Hi Robert,
Jacek Rudnicki schrieb:
Hi Michael,
You are right, the default settings for the PPC platform is
7372800/16.
You can modify the default settings in the file:
…/ser8250/ppc/sys_ttyinit.c from the ddk-devc-ser8250 package.
yes, I know.
But QNX is delivering standard binaries of devc-ser8250 inside the
Momentics installation, where the default clock frequency depends on
the target architecture.
This binaries have no relation to any BSP or DDK source tree.
So, why are the default frequencies different?
Regards
Michael
Regards
Robert Dobrus
Uzytkownik “Michael Tasche” <> michael.tasche@esd-electronics.com
napisal w wiadomosci news:> shqto4-vra.ln1@comm.esd> …
Hi,
if I understand the documentation correctly, the default for the
devc-ser8250 is (-c 1843200/16).
This is not true for the PPC Binaries.
I think, the binaries devc-ser8250, delivered with the Momentics
installation, should use “1843200/16” per default independent of
the target architecture.
If not, we need some clarification in the Docu.
I do not want to be fussy, but if you deliver a PC compatible
serial board, customers with PPC-Targets have to use the “-c xxxx”
option.
What is your opinion?
Kind Regards
Michael