11 replies to this topic

[Arron Chapman]

I'm trying to get this eeprom [PDF] working but I'm having some trouble getting it going.

This is my current test code:

I2CDevice eeprom = new I2CDevice(new I2CDevice.Configuration(1, 400));

byte[] buffer = new byte[6];
I2CDevice.I2CReadTransaction read = I2CDevice.CreateReadTransaction(buffer);
eeprom .Execute(new I2CDevice.I2CTransaction[]{read}, 1000);

This code produces this result:




A few Thoughts:

• The datasheet says that the control bit should be: 10100001 to do a read from the first half of the first chip on the bus, is this what is output when I create a ReadTransaction?
• How can I figure out exactly what bits are being transferred when I do a read/write transaction?

[Nathan Baker]

I can confirm that the chip is indeed working as he has it wired, as it worked on my arduino. We just can't seem to figure out exactly how to code this in .NET.

[Chris Walker]

According to page 12 of the datasheet, you need to use the repeated start bit feature to read data from the EEPROM. Have you tried using the repeated-start-bit extension to I2C? Chris

[Arron Chapman]

According to page 12 of the datasheet, you need to use the repeated start bit feature to read data from the EEPROM.

Have you tried using the repeated-start-bit extension to I2C?

Chris

I flashed the 4.1.1 Beta 1 firmware, how exactly do I use the repeated start bit? If it just involves using the 2 methods your provided (in another thread). Then yes I have with similar results, "Setup Write to ['2' (0x02]]"
.

[CW2]

I don't think you've got the slave address right. According to the datasheet, it is 1010 B0 A1 A0, so if you wired chip address inputs A1 to 0 and A0 to 1, then the slave address for block 0 is 1010001 = 0x51. The device must respond with acknowledge (ACK), NAK in your screenshot means the address is not valid (resp. there is no device with such address present on the bus).

[Arron Chapman]

I don't think you've got the slave address right. According to the datasheet, it is 1010 B0 A1 A0, so if you wired chip address inputs A1 to 0 and A0 to 1, then the slave address for block 0 is 1010001 = 0x51. The device must respond with acknowledge (ACK), NAK in your screenshot means the address is not valid (resp. there is no device with such address present on the bus).

I misunderstood what you ment when I first rad that, after re-reading it, and reviewing the code it clicked.
I was able to send a successful write.


However when I read something is going wrong.



The current code is:

I2CDevice eeprom = new I2CDevice(new I2CDevice.Configuration(0x50, 400));


I2CDevice.I2CWriteTransaction write = CreateWriteTransaction(new byte[] {0x24}, 0, 2);
byte[] buffer = new byte[6];
I2CDevice.I2CReadTransaction read = CreateReadTransaction(buffer, 0, 2);
eeprom.Execute(new I2CDevice.I2CTransaction[] { write }, 1000);
eeprom.Execute(new I2CDevice.I2CTransaction[] { read }, 1000);

I have A0 and A1 wired to GND, which makes them both 0. So my address is 0x50.

[CW2]

I have A0 and A1 wired to GND, which if I'm not mistaken makes them both 0.

Then the slave address (for block 0) is 1010000 = 0x50.

Attached Files

•  ControlByte.png   7.25KB   24 downloads

[Arron Chapman]

Then the slave address (for block 0) is 1010000 = 0x50.

Indeed, see my edit above.

[CW2]

However when I read something is going wrong.

Try adding Thread.Sleep(5) (which is max. write cycle time) before you read the byte back.

[Stefan W.]

Out of interest, what's that software you are showing in the images (not fritzing )?

[CW2]

Do you mean waveform captures? Those are Saleae Logic analyzer screenshots.

[Arron Chapman]

Out of interest, what's that software you are showing in the images (not fritzing )?

Do you mean waveform captures? Those are Saleae Logic analyzer screenshots.

That would be correct, that is from my Logic.