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spamiam
Joined: 13 Nov 2005
Posts: 661
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Posted: 26 April 2006, 23:23 PM Post subject: Re: SD |
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| zbasicandy wrote: | | Quote: | I have found that I can not use the built-in SPI functions because I
need to keep the Card-Select selected over a bunch of transfers, and
when the CS is deselected, apparently the transaction in progress is
lost. |
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Yep, I think I wrote that! It is too bad because the S/W SPI was SO slow in my hands. Maybe it can be tweaked for better speed, but I did not see any clear bottlenecks.
So, the high level interface with a not too pokey 115,200bps is a pretty good alternative.
It is funny, the ZX's ATMega32 driving the SD board's ATMega64!
-Tony
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zbasicandy
Joined: 26 Jan 2006
Posts: 193
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Posted: 28 April 2006, 2:00 AM Post subject: SD card interface to ZX-xx |
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Image Notes:
To show the ZBasic users that I do not produce vaporware .... I make sure it works even with the software!
The black polorized connector on the SD card goes to the firmware download port on the left side. The wires goes directly to a RS232 connector for firmware downloading.
The center glowing Led indicates card insertion and MCU operation.
I used a Radio Shack perf board to mount and wire the SD interface card.
The wires from the SD (pointing top) goes to an inline RS232 converter from (Acroname.com) then goes to the male RS232 connector on the Super Com Z. There is a jumper on the Super Com Z which powers the RS232 convertor and the SD interface from pin 9 (jumper selectable).
Notice the 256 meg card ($17) - Using a 2 gig card is a waste of money for this application. I was told the minimum card you can buy now days is 128K?
| Description: |
| Image of Comfiletech SD interface module connected to a ZBasic ZX-40 microcontroller e.g. Super Com Z |
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Download |
| Filename: |
DSCN0532.zip |
| Filesize: |
193.86 KB |
| Downloaded: |
3234 Time(s) |
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dkinzer
Site Admin
Joined: 03 Sep 2005
Posts: 2493
Location: Portland, OR
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Posted: 03 May 2006, 23:27 PM Post subject: |
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| Quote: | | The ZBasic SPICmd() procedure is capable of transferring a maximum of 255 bytes... |
The SPICmd() routine has been updated to allow the transfer count to be a 16-bit value. This may allow the ZX to interface to large capacity devices like SD/MMC that require page writes of 512 bytes.
The I2CCmd() routine has been similarly updated. The changes have been made in a way that is backward compatible meaning that existing code does not have to be recompiled. Essentially, there are two versions of each API in the VM - one that uses 8-bit count and one that uses 16-bit counts. The 8-bit API just calls the 16-bit service code after setting the high byte of the count to zero.
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