Dual Programmable Gain Amplifiers LTC6912 and DSPic30f4011

[Murray11]

Hello everyone

I am working on a project for my bachellor degree, and I have to stopped because I can't set up a programmable amplifier LTC6912-1. I read some post about problems with this dual amplifier but all of them are about spartan 3e board.**broken link removed** The circuit is in the drawing that I upploaded.

Part of the code are:

**broken link removed**


Where RE2 is wired to CS of the LTC6912

The SPI Master is SET... SPI1CON = 0x032D; and SPI1STAT = 0x8000; The Fcy of the instruction is 16 Msps. and the prescaler of the spi is set to work more or less at 0.8 KHz.

I can't get the correct value of the Gain, I changed the gain to 0x33 and 0x66 and I have never took the correct or a repetitive gain.

The Dout of the SPI is working and also the SPI CLK because I cheked it with an Osciloscope.

RE2 goes down before sent the data!

Do you know an idea of what could be or what I missing?

Thanks a lot

 

[Murray11]

Thanks a lot, I will Try. I am new in this Forum.

Sorry I tryed but a couldn't

 

[BradtheRad]

Now your schematic is visible.

 

[KlausST]

Hi,

All the necessary informations including timing and voltage levels are in the datasheet.
Please read it carefully, especially the timing diagrams. Compare them with what you see on your scope.

Btw: controlling this device is independent if you use a microcontroller or a PLD, the signals must be the same.

Show us your code and scope pictures.

Klaus

 

[pic.programmer]

What device you want to use to control the LTC device ? Microcontroller or PLD ? Mention the device name.

 

[FvM]

Insiders know that the device is a PIC24.

I get a SPI clock frequency of 500 kHz and correct mode 0, so everything should be fine, presumed you are setting CS high again after the transmission. It should be also easy to clock in all '0' or '1' for test. Can it be an analog circuit problem?