I2C Cracked - next SPI.... - Electronic Circuits Projects Diagrams Free

UTMonkey · 15th April 2008, 08:37 PM

Hi all,

Got my I2C routines to work with a DS1307 and a 18F2550.

The next step I suppose is to have a tinker with SPI, I do have some RTC's coming from MAXIM so I shall have something to play with in the next couple of days.

I am very interested in data logging projects that are out there and I have read that SD cards can be read via SPI.

Great! however with the reading I have done so far, I have 2 questions

1. Where is the "official" documentation on interfacing with a SD via SPI?
2. I have read that FAT16 is copyrighted, if I was to develop and sell a product which incorporated the FAT structure - would I have to pay "Bill"?

Thanks

Mark

eng1 · 15th April 2008, 08:48 PM

Check out Microchip Application Note 1045.

Link added

futz · 16th April 2008, 12:14 AM

Quote:

Originally Posted by UTMonkey

Got my I2C routines to work with a DS1307 and a 18F2550.

I don't think I've ever (successfully) done I2C, but I have done SPI.

Quote:

The next step I suppose is to have a tinker with SPI, I do have some RTC's coming from MAXIM so I shall have something to play with in the next couple of days.

SPI is super easy. Nothin to it.

Quote:

I am very interested in data logging projects that are out there and I have read that SD cards can be read via SPI.

I'm working on exactly that right now. I have it all wired up and am just trying to puzzle out how to do the software. It's tougher than I expected, but I'll get it.

18F4620_sdcard002sm.jpg

That's a 18F4620 with a Futurlec SD/MMC Mini Board and a Logic Converter Mini Board. SD's are 3.3V. You can use voltage dividers, but I had one of these boards so...

Quote:

1. Where is the "official" documentation on interfacing with a SD via SPI?

Unknown. But I have some useful stuff for you:

This is a GOOD one, and hard to find: sdcard_appnote_foust.pdf

This is the useful part of the MAXIM info in open document format: sdcard_info.zip

Toshiba SD Card Spec: TOSHIBA_SD_Card_Specification.pdf

Some links:
http://www.k9spud.com/sdcard/
http://www.kronosrobotics.com/Projects/MMC.shtml
http://uanr.com/sdfloppy/
http://www.roland-riegel.de/sd-reader/index.html
http://pinouts.ru/Memory/sdcard_pinout.shtml
http://www.technick.net/public/code/...onmem_sdcard_9
http://www.maxim-ic.com/appnotes.cfm/an_pk/3969
http://www.captain.at/electronics/pic-mmc/
http://www.mcu.fluxfocus.com/documents/SDSPI/sdspi.htm
http://www.maxim-ic.com/appnotes.cfm...te_number/4068

blueroomelectronics · 16th April 2008, 12:36 AM

Since you have both a PICkit2 & a Junebug use one for the Logic Analyzer and watch the SPI or I2C bus.
I've got to try that myself

futz · 16th April 2008, 12:37 AM

Quote:

Originally Posted by blueroomelectronics

Since you have both a PICkit2 & a Junebug use one for the Logic Analyzer and watch the SPI or I2C bus.
I've got to try that myself

Ya! I'm gonna do that!

blueroomelectronics · 16th April 2008, 12:47 AM

Post your results, you'll need to convert the BMP to PNG or GIF.

donniedj · 16th April 2008, 12:53 AM

Have you considered using a micro with built in RTCC? The 24F series has an RTCC and supports USB called the 24FJ256GB faimily. 24F is relatively new and the USB versions are brand new. Few are aware of them.

Cracked? Did you implement your own software I2C? Its not cracked until you do this, otherwise it is only bruised.

**3v0** · 16th April 2008, 05:05 AM

The C18 compiler has software/BitBang support for I2C in library sw_I2C.h.

I used it to to read back sound files programmed into the EEPROMs with a Junebug. The tools are getting nice.

Futz, FWIW...I see your Junebug is not mounted. In the early days of electronics people used to mount projects on wood blocks. I still like that method, cut a block to the size of the board and use standoffs to mount the board. It makes it easier to work with, slides around less.

blueroomelectronics · 16th April 2008, 01:05 PM

I've got to find a supplier of the BT-04 case, dipmicro sells em with a PCB for $6.40 The Junebug PCBs need about 0.5mm sanded off the bottom to fit perfectly. Now where to get the super tiny screws...
http://www.dipmicro.com/store/index....&productId=596

futz · 16th April 2008, 02:28 PM

Quote:

Originally Posted by 3v0

Futz, FWIW...I see your Junebug is not mounted.

It's on little rubber (polyurethane) "feet". Five of them, four at the corners and one under the buttons. Doesn't slide all that much.

Quote:

I've got to find a supplier of the BT-04 case, dipmicro sells em with a PCB for $6.40 The Junebug PCBs need about 0.5mm sanded off the bottom to fit perfectly. Now where to get the super tiny screws...

I have one of those. Bought it from DipMicro with the PCB for $6.40.

The screws come with it. I dithered about installing Junebug in it for a while. Decided not to for now.

UTMonkey · 16th April 2008, 08:40 PM

Cheers Futz, some great info there.

I don't know if you recommend this, but I would like to be able to build the modules you describe from scratch (SD and Logic Converter boards), I would still categorise myself as a newbie so think this may be useful, what do you think?

I think when I manage to fathom access to the SD via SPI I will start to look at some FAT routines, I might try doing it in ASM (yes I must like pain).

Quote:

Cracked? Did you implement your own software I2C? Its not cracked until you do this, otherwise it is only bruised.

- DonnieDJ

Software I2C? I did it using the MSSP module of the 18F2550, is doing it in software tough?

Thanks again

Mark

futz · 17th April 2008, 02:04 AM

Quote:

Originally Posted by UTMonkey

I don't know if you recommend this, but I would like to be able to build the modules you describe from scratch (SD and Logic Converter boards), I would still categorise myself as a newbie so think this may be useful, what do you think?

Certainly. There's nothing complex about these boards. They're just time savers, and if you count the time it took me to make all the connectors, more like time sinks.

If you want schematics just ask. The 5V to 3.3V chip is a LCX245. That board also has a 3.3V regulator on it. The SD socket board has jumpered pullups for the SD lines, a couple LEDs, a cap and the socket.

Quote:

I think when I manage to fathom access to the SD via SPI I will start to look at some FAT routines, I might try doing it in ASM (yes I must like pain).

Ya, I plan to do it raw first too, and then worry about the filesystem. Asm isn't painful! It's nice! But I'm a C guy these days.

Someone Electro · 26th June 2008, 06:15 PM

Why don't you simply use the microchips app note for FAT16 and FAT32. I used it and it worked on the first try!

15th April 2008, 08:37 PM	(permalink)
UTMonkey Experienced Member	I2C Cracked - next SPI.... Hi all, Got my I2C routines to work with a DS1307 and a 18F2550. The next step I suppose is to have a tinker with SPI, I do have some RTC's coming from MAXIM so I shall have something to play with in the next couple of days. I am very interested in data logging projects that are out there and I have read that SD cards can be read via SPI. Great! however with the reading I have done so far, I have 2 questions 1. Where is the "official" documentation on interfacing with a SD via SPI? 2. I have read that FAT16 is copyrighted, if I was to develop and sell a product which incorporated the FAT structure - would I have to pay "Bill"? Thanks Mark

15th April 2008, 08:48 PM	(permalink)
eng1 Experienced Member	Check out Microchip Application Note 1045. Link added Last edited by eng1; 15th April 2008 at 08:55 PM.

16th April 2008, 12:36 AM	(permalink)
blueroomelectronics Experienced Member Blog Entries: 4	Since you have both a PICkit2 & a Junebug use one for the Logic Analyzer and watch the SPI or I2C bus. I've got to try that myself __________________ Bill Smart Kits build Smart People http://www.blueroomelectronics.com

16th April 2008, 12:47 AM	(permalink)
blueroomelectronics Experienced Member Blog Entries: 4	Post your results, you'll need to convert the BMP to PNG or GIF. __________________ Bill Smart Kits build Smart People http://www.blueroomelectronics.com

16th April 2008, 12:53 AM	(permalink)
donniedj Experienced Member	Have you considered using a micro with built in RTCC? The 24F series has an RTCC and supports USB called the 24FJ256GB faimily. 24F is relatively new and the USB versions are brand new. Few are aware of them. Cracked? Did you implement your own software I2C? Its not cracked until you do this, otherwise it is only bruised. __________________ I can still log in! Delete my account and all my post now.

16th April 2008, 05:05 AM	(permalink)
3v0 Moderator Blog Entries: 3	The C18 compiler has software/BitBang support for I2C in library sw_I2C.h. I used it to to read back sound files programmed into the EEPROMs with a Junebug. The tools are getting nice. Futz, FWIW...I see your Junebug is not mounted. In the early days of electronics people used to mount projects on wood blocks. I still like that method, cut a block to the size of the board and use standoffs to mount the board. It makes it easier to work with, slides around less. __________________ search engine for electronic parts Junebug USB PIC programmer kit. USB Bit Wacker Last edited by 3v0; 16th April 2008 at 05:10 AM.

16th April 2008, 01:05 PM	(permalink)
blueroomelectronics Experienced Member Blog Entries: 4	I've got to find a supplier of the BT-04 case, dipmicro sells em with a PCB for $6.40 The Junebug PCBs need about 0.5mm sanded off the bottom to fit perfectly. Now where to get the super tiny screws... http://www.dipmicro.com/store/index....&productId=596 __________________ Bill Smart Kits build Smart People http://www.blueroomelectronics.com

26th June 2008, 06:15 PM	(permalink)
Someone Electro Experienced Member	Why don't you simply use the microchips app note for FAT16 and FAT32. I used it and it worked on the first try! __________________ Il give you shocking experience.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Latest
SPI->I2C Converter	dknguyen	Datasheet/Parts Requests	16	12th March 2008 01:45 AM
Winbond SP03 i2c bitbang	MikeC	Micro Controllers	0	22nd February 2008 05:08 PM
SPI Testing with ENC28J60	mikesmixes777	Micro Controllers	9	17th January 2008 07:41 AM
Both parallel and spi in PIC microcontroller PLEASE HELP	jitun2	Micro Controllers	12	24th October 2007 02:08 PM
Need help! I2c data bus with pic 16f84a	rukshankb	Micro Controllers	2	7th October 2007 11:57 AM