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PPcenter. Arts and craft for my Sega Saturn. Since 1847 :D

Could finally write a file to my SD card :]

Written by cafealpha 3 comments
I could finally write a file to my SD card ... from my Saturn
Well, I just tested by dumping my Saturn's BIOS, and didn't tried further, because I don't want to find and fix other bugs today

data/images/20150716_bios_dump_ok.tb.png
Top : my Saturn BIOS, dumped from my Freewing device 5 years ago
Bottom : BIOS file in my SD card dumped today
Hex Editor says that both files are identical

This fixes a nearly 3 years old bug
At that time, I connected a SD card to my second pad port on my Saturn and could read files successfully. However, file write sometimes failed ... I thought about many possible causes of failures (not enough 3.3V power supply ? Bad luck ? etc etc), but it was a software bug : writing sectors to SD card actually takes longer than reading sectors, and I didn't waited enough for my SD card to finish write.
Changing poll timeout count from 500 clocks to 50000 clocks seems to fix the problem. (Q&D fix, but if it works fine, I won't change it )

So now, as SD card read/write access works on both yabause and real hardware, it is time to to use it in order to develop new features for my Saturn

data/images/20150716_memcart_rev2f.tb.jpg
My SD card cartridge for Saturn (Q&D prototype revision )

Edit : wow, current cartridge firmware build ID (incremented on each make/build) is 4200

3 comments

#1  - hitomi2500 said :

Congratulations! Is that a hippo in the bottomleft corner? And is that a MAX3000? They're almost as ancient as saturns themselves (CPLDs, not hippos).

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#2  - cafealpha said :

@hitomi2500 : Hi, well, it is a cow, but it could be anything else because of poor rendering on PCB silkscreen :D

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#3  - cafealpha said :

@hitomi2500 : And yes, it is a MAX3000 CPLD, "the simpler the better", and this CPLD is kind enough to offer 5V <-> 3.3V interface. This cartridge mostly uses ancient parts, because I don't have enough experience with modern ones ^^;

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