Hi Nimish > To be more specific, we would like to change the attenuation in the > KatADC RF front end every 20 ms and we can allow up to 1 ms of dead > time/settling time. Do you think this can work?
Just had a quick look through the IIC controller. Seems to need to write around 12 words, each 8 bits in size, using a 100kHz clock. This equates to around (10us * 12 * 8) ~= 1ms to change attenuation values so 20ms should be enough. I am not sure about the settling time of the programmable attenuator. > A related question is how to change this attenuation. I tried using a > software register connected to atten* inputs of the KatADC yellow > block, but the design would not compile. I have not got time to check > at what stage it fails, but I can look into that. I got the design > compiled by connecting just the "constant" blocks to these inputs. Is > it first of all allowed to have a software register there? If not, > what would be the way to change this attenuation dynamically? > We have software registers that control this value in designs here. If software registers work in other parts of your design, they should work here - there is nothing special about those ports. You can also set these values in software from the PPC if that is easier, the IIC controller can be accessed from the PPC. Regards Andrew
