| Should we have a SD card slot in the calc? |
| Yes |
|
66% |
[ 8 ] |
| No |
|
33% |
[ 4 ] |
|
| Total Votes : 12 |
|
willrandship wrote:
Ever heard of Bit-Banging, also called Bit-bashing? It's a concept which allows you to access SD data, and write to SD, with only standard IO pins. It's also why you can make hardware that goes into the sd slot, that isn't a storage device.
So, SD is good after all? Yay! No need for usb then, right?
Well, you've oversimplified the concept of bit-banging pretty momentously, but in the end, yes, accessing the SD card directly via I/O pins instead of from a dedicated host controller is indeed bit-banging. Then again, every TI-83/83+/84+ peripheral project like my networking projects with CALCnet, Ben Ryves' Emerson library, my own TICI attempts and PS/2, and QuadPlay / mobileTunes 3 / all other sound programs for the calculators are just bit-banging. 
Yeah, you people know much more about it than me
willrandship wrote:
Yeah, you people know much more about it than me
I still think USB is good
SD card is nice too, but you will definitely need a controller + FAT32 drivers.
alberthrocks wrote:
I still think USB is good
SD card is nice too, but you will definitely need a controller + FAT32 drivers.
Just didn't read the whole thing.
Good idea tho
alberthrocks wrote:
Just didn't read the whole thing.
Good idea tho
The downsides of the bitbanging approach, of course, are that (1) it requires more thought from the CPU, and (2) that it takes up data lines that could otherwise be used for something else. I assume if we use the eZ80, we'll need a bus arbitration chip, like the one that was in that custom ASIC in the 83+s and is now part of the CPU/RAM ASIC in the 84s?
Bit-banging still doesn't solve the issue of licensing, or did I miss something where we are able to get around that? Also USB would allow for using SD Cards, as BrandonW has done so with MSD8X and USB SD card readers, though it did require extra power.
TheStorm wrote:
Bit-banging still doesn't solve the issue of licensing, or did I miss something where we are able to get around that? Also USB would allow for using SD Cards, as BrandonW has done so with MSD8X and USB SD card readers, though it did require extra power.
You missed where BenRyves pointed out that there are some free and open specs for SD things for many circumstances. And that's true about USB, although you'd then need to write the appropriate USB drivers.
KermMartian wrote:
TheStorm wrote:
Bit-banging still doesn't solve the issue of licensing, or did I miss something where we are able to get around that? Also USB would allow for using SD Cards, as BrandonW has done so with MSD8X and USB SD card readers, though it did require extra power.
You missed where BenRyves pointed out that there are some free and open specs for SD things for many circumstances. And that's true about USB, although you'd then need to write the appropriate USB drivers.
Definitely. Did anyone spec out how much the physical socket would cost? Sparkfun has an
SD/MMC card socket for $4 each, so I'm sure we could pay $3 or $2.50 in quantity and from a cheaper supplier.
KermMartian wrote:
Definitely. Did anyone spec out how much the physical socket would cost? Sparkfun has an
SD/MMC card socket for $4 each, so I'm sure we could pay $3 or $2.50 in quantity and from a cheaper supplier.
TheStorm wrote:
KermMartian wrote:
Definitely. Did anyone spec out how much the physical socket would cost? Sparkfun has an
SD/MMC card socket for $4 each, so I'm sure we could pay $3 or $2.50 in quantity and from a cheaper supplier.
microSD cards do not have to implement the SPI/MMC mode (though all of the ones I've tried do) so they may not work.
As for sourcing sockets for SD cards, I bought a cheap card reader from a pound shop (so costing £1) and desoldered the connector. Much cheaper than buying the sockets individually, though requiring a bit more work. The contacts on SD cards are spaced 0.1" apart, so it's relatively simple to make your own connectors too.
I pay the same for a 2G micro as a 4G regular. I only like to use them in more permanent storage, like my DS Flashcart. Reg SD is much more durable.
http://www.mouser.com/ProductDetail/3M-Electronic-Solutions-Division/SD-RSMT-2-MQ/?qs=sGAEpiMZZMtaouNQoacPIDlbfnt3p4I4itkBBeOC%252bPc%3d
Here's a nice, cheap SD connector, $1.30 for 1! $0.89 for 500!
I assume you mean $0.89 per unit for 500.
merthsoft wrote:
I assume you mean $0.89 per unit for 500.
Indeed. Willrandship, ah, that's even cheaper than I was expecting from Mouser. BenRyves, that's my strategy to get cheap USB sockets as well, except here in the US we go to $0.99 stores.
That's all folks!
Voting is now closed, and votes will now be tallied.
The final feature list will be announced soon, so stay tuned.
Thanks to everyone who voted!
I believe the overall verdict was a bit-banged full-sized SD card slot here?
Register to Join the Conversation
Have your own thoughts to add to this or any other topic? Want to ask a question, offer a suggestion, share your own programs and projects, upload a file to the file archives, get help with calculator and computer programming, or simply chat with like-minded coders and tech and calculator enthusiasts via the site-wide AJAX SAX widget? Registration for a free Cemetech account only takes a minute.
»
Go to Registration page
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
