I wanted to know if the ADE7758 Samples have any limitations compared with the real ones that I can buy in every online store for electronic stuff. Does it have limitations?
Kindly contact your local Analog Devices Inc. Sales and Distribution representatives to know about the sampling quantities and limitations. Click on this link to view the offices listed.
I know that the limit is 2 chip per sample request. You didn't understand my question. I asked if the chip ADE7758 sample has all the features and works equally as it was bought in Digi-Key or in other electronic store.
Also I wanted to ask you another thing. I have the chip ADE7758 and 2 weeks ago it was working normally, but now it doesn't work right. Sometimes I get 0x00 when I read the registers and other times I get the correct value. Also I can't write new values inside the chip. This problem is from the chip or is mine?
The sampled ICs will also have the same features, unless otherwise notified specifically.
Can you elaborate on the problem you are facing? Which register are you reading? Are you reading all registers and seeing the same issue? When the read-back doesn't work, does the IC power up at all, or is it the communication that doesn't work? Does this happen on one IC or all ICs? Can you think of anything else that might have changed in the meanwhile.
Before starting explaining how I'm doing it, I want to say that I have the ADE7758 chip welded in a PCB. I did solder the ADE7758 with 300ºC and didn't baked for 24 hours at 125ºC prior to board mount. That's why it's not working right?
The part with a circle in red should be connected to the ground?
Here are the steps that I followed to make the chip work but with no progress:
Kindly refer to the absolute maximum ratings on page 8 of the datasheet. I believe you have exceeded these temperature values and hence the chip fails to work as before. Did you subject the chip to such high temperature after the chip was used the first time(when it worked)? The short circuit event that you are mentioning might also have caused this failure to happen. Did you check if the on-chip reference is up, when the part is powered back ON? pin12 must be 2.4V after power-up.
Ok, I'm going to try it next week at the laboratory.
I'm using SPI with mode 2 and frequency of 10MHz. Is that ok?
Which mode 2 are you referring to? And 10 MHz is the maximum allowed frequency. If you can afford to go a little lower, I would recommend so. Even if not, you should be fine. Look into other timing specs as well.
The SPI Mode depends in how the chip works in sending the data via SPI. You can see more here http://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus#Mode_numbers . I'm using the SPI mode 3, as it's the only one that gives the correct data for the registers - I tried to read the register 0x48 and it gave 0x3F, so it's right.
Now I'm using a new PCB with the ADE7758 less that 1cm away from the microcontroller, instead of the old PCB where I had it more than 6cm away. I'm using the 1MHz frequency for the SPI connection but I think maybe is still high as my microcontroller sometimes can't get the right value.
It looks like Mode 1 would make more sense as the default SCLK should be low. What happened when you used this setting?
By looking at the ADE7758 I see that the SPI mode needs to be the MODE 1, but if I use the MODE 1 to read the registers from the mbed microcontroller I don't receive the right value - I receive 0x00 or 0xFF.
please use the oscilloscope to capture the 4 signals of the SPI communication (CS\, SCLK, DIN and DOUT) when you read LCYCMODE register default value (you should read 0x78). The behavior should match the one from the data sheet (rev E, page 58, figure 94). In this way, you can see if the ADE7758 sends out the right value and understand if the ADE7758 or the microcontroller creates the problem.
With the new PCB I'm able to use the mode 1, but if I connect the transformer to the electricity I read the register with errors. What do you think is this error?
what transformer are you talking about? It may be a current transformer or a voltage transformer or the transformer used in the power supply. Please look at the SPI pins with the oscilloscope to see what errors appear and the integrity of the signals. Then you may understand what is going on.
I'm using a voltage transformer like this one: http://www.clickplus.pt/pt/product/show_details/30348/Transformador-ACAC-Encapsulado-Primario-230V-Secundario-6V-24VA
Could you please provide more details like a schematic which shows what changes you make to the circuit and indicate how this effects the SPI communication? Please also indicate whether you are able to read default register values through SPI like LCYCMODE register or if this is a problem reading other registers.
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