Hi, I have a problem with ADA3023 since I cannot read the conversion with a dPIC, first of all the first thing I have done is the following check:there is a voltage of 5V and + -15V. In the ACAP PIN, RCAP and REFIN there are 2.5V and in REF1.2 = 4.096V, I have left the default CFFF register FFFF and use the datasheet initialization sequence for the power supply.
After these checks I have done the ADC readings by the sPI and they fluctuated. After analyzing with the oscilloscope I have noticed that the BUsY PIN does not change, it is always at zero it does not warn that the conversion is finished. I have changed the ADA3023 for two times for a new one, assuming this was a problem but the PIN BUsY remains the same.
I don't know what else I can do!
Can you tell me a bit more about how you have the device serial interface connected? For example is CS always driven low?
Hi, thank you very much for answering.
the communications are controlled by the dsPIC
This is the sequence I use to activate the ADAs and read the sDO output
L_ADAS_RESET = 1; L_ADAS_PD = 1; L_ADAS_CNV = 0; L_ALIM_CS_DVDD = 0; L_ALIM_CS_AVDD = 0; L_ALIM_CS_VDD = 0; __delay_ms(100); L_ALIM_CS_VDD = 1; __delay_ms(1); L_ALIM_CS_DVDD = 1; __delay_ms(1); L_ALIM_CS_AVDD = 1; __delay_ms(200);
L_ADAS_PD = 0; __delay_ms(100); L_ADAS_RESET = 0; __delay_ms(200);
L_ENABLE_CS = 1; L_ADAS_CNV = 0; __delay_us(10); L_ADAS_CNV = 1; __delay_us(5); L_ADAS_CNV = 0; __delay_us(20);L_ENABLE_CS = 0; result1 = SPI1_WR(0xFFFF);L_ENABLE_CS = 1;
The red channel in the Cs PIN and the yellow one the CNV PIN.
If you added the BUSY signal to your oscillogram would you expect to see that the output is always zero? If the part is converting I would expect to see BUSY go high a short time after CNV and using your timing to have completed before CNV goes low with your timing. Let's double check just to make sure we aren't missing it. The BUSY should be approximately 6us wide for 8 channels converted simultaneously.
I did also note a couple of issues with your schematic that you'll want to address in a future revision.
1) The exposed paddle (EP) should be tied to the lowest potential (i.e. VSSH)
2) Both REFN and REFN_2 need to be connected to AGND
3) ACAP and DCAP should NOT be shorted together. Each should have their own separate decoupling.
Based on your symbol for the product I would also recommend downloading the latest datasheet as it appears as if you may be working off a pre-release version.
Tomorrow I will check the BUsY signal again, but until today when I activate the CNV, the BUY PIN is always zero, it never changes, I checked it with the oscilloscope. It is very strange.
Thank you for your help, and for the review.
1) It's true, I forgot to put the PIN (EP) to VssH.
Thank you very much for the recommendations
Today I checked the BUsY PIN again and it doesn't work. I attached the image of the oscilloscope. red channel CNV yellow channel BUsY
I don't know what may be happening