On Thu, Aug 30, 2007 at 01:05:32PM +0200, Carl-Daniel Hailfinger wrote:
On 30.08.2007 06:19, ron minnich wrote:
On 8/29/07, Carl-Daniel Hailfinger c-d.hailfinger.devel.2006@gmx.net wrote:
I'd say it should accept a lar archive via serial console, perhaps using ymodem, and start executing the first member of the lar.
A bit more detailed: If the BIOS fails to verify its checksum, it outputs a message telling you about it over serial, waits for signature to arrive over serial (a standard char sequence with repetitions at the beginning), reads until it has one complete signature, switches serial to ymodem and accepts a lar archive. The first member of the lar is then executed.
The "wait for signature" is there to allow people to use multiple tries getting serial speed right. OTOH, if the code outputs a continuous stream of "TESTTEXT\n" while waiting for serial input, the other side can verify serial speed settings as well.
What do you think?
That's the way to go.
Can we invert the speaker line each time a byte is written out over serial? With 115200,8,N,1 we would get an inversion frequency of 11.52kHz and a tone frequency of 5.76kHz. Comparing that tone to some downloadable audio sample would allow people to find out if serial was driven with the right speed.
Should be doable. Have a look at arch/x86/speaker.c in v3 for sample code if you want to give it a try.
Uwe.