Sunday, February 24, 2013

Some notes on accessing track 0 on SGSBCSD

Well, I've told that C000h TPA (strictly speaking, not TPA, but start of CCP) based CP/M image starts from track 0 / sector 0, the C200h system should start from SD offset 200h - i.e. track 0 / sector 1,D000h TPA - from track 0 / sector 8 That leads to a significant problem: everything works until you do not try to rewrite/regenerate CP/M itself inside of SBC, because the changes will we written to track 0 / sector 0 which will led to unusable boot image. So, if you want to do system change inside of SBC - use C000h based systems for now. In future I plan to change the algorythm of accessing track 0. Saying we have C800h TPA system starting from sector 4 and trying to write track 0/sector 0. I will add 4 to sector number so you'll access sector 4 as expected. That will lead to the situation you will not be able to access track 0 sector 0-3 at all. I think this is not a significant loss.

Wednesday, February 6, 2013

Tuesday, February 5, 2013

Bugfix release 2322

I had an awfull error writing sector. I waited just 255 times for non-zero byte after SD_CMD24 command.
It was wrong. Now I wait for FFFF ticks max - that works with my Apacer 1G card.

I hope next weekend I'll go to the Mitino market and buy a pocket of the most strange SD and MMC cards to test.
The release, as usually, here

UPD: I've attached c-kermit (version 2.2/IOBYTE) on the disk image inside of distribution. And it's even possible to transmit something.
On the CP/M side, tell kermit
set port tty
On unix side, tell your local kermit
set streaming off
and something somehows transmits, but with a huge number of errors. That's a topic to be explored.

Saturday, February 2, 2013