[ECOS] EDOSK2674 Serial Driver

Uwe Kindler ukindler@htwm.de
Thu Nov 6 08:24:00 GMT 2003


I failed finishing the serial tests which require ser_filter - all other
serial tests finished successfully. I tried to run these tests with
115200 baud for the serial port.

After these tests failed, I created a simple application with one thread
that simply receives a number of bytes from
the serial driver and then again sends these data via the serial driver.
Then I run this test and entered something on
the console - everything works fine. But then I sent a 260 Byte text file
and the driver received only 16 Bytes.
Then the received bytes where then send back to the console and I saw on the
console screen that the driver
missed a lot of bytes because receive interrupts are enabled again in the
receive DSR.

Then I recompiled the kernel and used a fixed table for DSR instead of a
list . When I now send the 260 Byte file
with 115200 baud then I received 56 Bytes. That would mean, the fastest save
baud rate would be
14400 for the 33 Mhz EDOSK board when using the serial driver with DSR.

The serial driver is based on the SCI driver from the SH architecture
because the H8S SCI is almost the same.
I did only some minor modifications so this driver should be well tested
with SH architecture.

Could someone confirm, that this is a normal speed for a driver. Is there a
comparable board with around
33 Mhz out there and what are the fastes baud rates for this board. Would it
be better in this case to drop the DSR and do
everything wthin the ISR and allow nested interrupts to occur so that the
serial driver does not block
high priority interrupts?

Thank you very much for your help

Best Regards, Uwe

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