DAC80501EVM: Eval board not working

Hi,

If you are closing JP2, essentially you shorted VDD to ground. How are you powering the device?

You have to give 3.3V to 5V as VDD on pin 1 of JP2 and 2 use as ground.

Regards,

AK

I’m not sure if we are talking about the same board. JP2 is for setting SPI2C to “0” so that the device operates in the SPI mode. 3.3V is supplied through J1.5. I`m using DAC80501EVM

Hi,

My mistake, I was referring to J2 connector.

Can you share scope shots of your SPI frame. what polarity are you using for SPI? Use one of the below modes.

Regards,

AK

Hi,

Can you send me the code? After power up, what is the internal reference voltage you are measuring?

Regards,

AK

Attached is the code. The reference voltage measures 2.5V (and I cannot shut down the internal reference).

dac8050x.zip

Hi,

Code looks fine to me. In code no need to write twice on address 0x04 (Gain Reg) 0x0100.

To me this looks like SPI frame issue. Can you send me CS, SDI and SCLK together in one scope shot?

send the command for power-down internal reference and take scope shot

Regards,

AK

Unfortunately I only have two channels on the scope. But we can use the clock signal to align to shots. Do you see why DAC80508EVM works fine while DAC80501EVM doesn’t work?

Hi,

Frame looks OK to me as you are sending 0x03, 0x01, 00.

Can you do the following to debug

Power up the device and follow the below register read/write operations

1. Read back the register 0x02, make sure this reads all zero ( DAC will be in asynchronous mode)

2. Read back CONFIG register at 0x03, this should read all zero

3. Write 0x0100 in GAIN register ( address 0x04)

4. Read back 0x04 to make sure the data is indeed 0x0100.

5. Read back STATUS register ( address 0x07) to make sure this reads all 0.

5. Write DAC_DATA

Regards,

AK

Hi,

This batch of boards are not faulty. I am using one of the EVM's from the same batch and it works fine. I don't have ready I2C codes for the device.

If you suspect EVM is damaged, I can arrange for a new EVM. Please send us your address to a.k@ti.com

Regards,

AK

We bought them from DigiKey. I’m surprised that both units we ordered have the same problem (and again DAC80508EVM works fine). I can try using I2C to communicate with the chip in the next few days. However we really want to use SPI for the higher speed and now we’re 100% sure SPI somehow is not working. What are your suggested course of actions besides further debugging?