9 replies to this topic

[pascal06]

Hello, I realize that the MCU AT91SAM7X512 have no EPROM, right ? Perhaps, related to embedded ethernet use on your roadmap, it would be a good idea to include also a little EPROM to be able to store some persitant information like IP address ... /pascal

[Chris Walker]

Good idea! There is an 8KB ".NET MF configuration sector" on the micro that we may be able to write a few KB of data into (such as your IP settings). There's also a 16KB "blank" area we've allocated to use for a future pre-bootloader...but we might be able to use part of that as a storage area as well. The limitation on both of these areas is that they're Flash, not EEPROM--so they'd be for writing "ocassional data" and not reading/writing data constantly. There's a bit of time overhead and Flash doesn't last as long as EEPROM (i.e. 10k+ writes vs 100k+ writes). Our short-term goal (i.e. the next 2-3 weeks) is to expose the FileSystem support so that you can read/write data to an SD card via SPI. I'm playing with early SD code here right now using the System.IO classes and it's pretty cool! We'll see what we can do to read/write a few KB of data in future revs of the firmware... Chris

[CW2]

Our short-term goal (i.e. the next 2-3 weeks) is to expose the FileSystem support so that you can read/write data to an SD card via SPI. I'm playing with early SD code here right now using the System.IO classes and it's pretty cool!

Should not be possible to simply connect any TWI/I²C compatible serial EEPROM (using analog input pins 4,5 switched to TWD/TWCK)?

[Chris Walker]

Should not be possible to simply connect any TWI/I²C compatible serial EEPROM (using analog input pins 4,5 switched to TWD/TWCK)?

Absolutely. And you can use either 3.3V or 5V I2C devices...just connect their power to the respective power header.

You'll need to write some C# code to interface with the EEPROM... Maybe we could put together a driver and do this in an upcoming tutorial as well. Would anyone be interested in that?

[krst]

yes, eeproom "driver" code would be nice, even though sd car gives more memory it feels easier easier and much cheaper to just throw in a small memory straight on the projects board on ..

[Charles]

Absolutely. And you can use either 3.3V or 5V I2C devices...just connect their power to the respective power header.

Not true...

I have a 24LC256 chip and it will not work with the Netduino...

http://forums.netdui...with-i2c-eeprom

Netduino firmware can not handle chips that require repeated start conditions.

In light of this, has anyone here successfully utilized EEPROM with a Netduino/N+? If so, please share the make and model number so the rest of us can avoid disappointment in the future.

[Chris Walker]

Hi Charles, If the microcontroller supports it, we should be able to add the repeated start bit functionality into the firmware. We just need a few simple test hardware configurations (and documentation for code implementation) that we can use to verify that we've made the proper enhancements. Chris

[Charles]

It was only $1.50, not even worth that I'm sure. I would much prefer to just move on to something that _works_ rather than make waves. I was hoping someone could simply suggest an IC that is known to work.

[Charles]

Any chance ExtendedWeakReference will get support for RecoverOrCreate functionality in the near future? What about allowing classes to be ISerializable??

[Chris Walker]

Any chance ExtendedWeakReference will get support for RecoverOrCreate functionality in the near future?

What about allowing classes to be ISerializable??

Charles,

I would recommend using an SD card and file system access. To enable ExtendedWeakReferences on the Netduino, we'd need to use 16KB of Flash that could otherwise be used for code.

Then again, maybe we could offer it as an option (i.e. pre-compiled firmware with ExtendedWeakReference space)?

Chris