AD9689 has fS × 4 mode and full bandwidth mode as per datasheet. We would like to configure it in custome mode, where user can change JESD configuration parameters through SPI interface. Please let us know if this is possible with this ADC.
Please let me know what modes the user wants to change to/from. In theory this is possible. but you have to understand that any time you change the JESD204B parameters (L, M, F, PLL line rate control register 0x056E), there is a chance that the PLL can become unlocked. This will require a PLL reset (link power cycle). When this happens, you will lose data from the analog pipe. The recommended way to change between JESD204B parameters is as follows
- power down JESD204B link
- apply new JESD204B parameters
- power up JESD204B link
<wait ~5ms for PLL lock>
Hope this helps.
We will follow the sequece you mentioned above.we want to use ADC with these settings : L = 8, M = 2, F = 2, S = 1, N` = 16, N = 8/10/12/16, CS = 0/1, CF = 0, HD = 0. Please let us know if we can configure in this way.
Please see datasheet for description of "FsX4" mode. Also please see memory map for setting up the FsX4 mode
We checked this section but we want S = 1 case, so please let us know if we can use that configuration.
The only supported mode in FsX4 is listed in the datasheet.
Thanks for clarification, can we customize link parameters in full band width mode?
I am not sure if I follow that question. Can you please be more specific as to what link parameters you want to customize? Please see tables 33, 34 and 35 to get the list of supported modes in full bandwidth mode. If you want to use the FsX4 mode, you will have to use the link parameters listed in the datasheet and in the memory map for register 0x0570.
I was asking about JESD link parameters to be set. In both fsx4 and full bandwidth modes they are fixed to some values can we change them? as i mentioned i want to set JESD link parameters as L = 8, M = 2, F = 2, S = 1, N` = 16, N = 8/10/12/16, CS = 0/1, CF = 0, HD = 0. Is this possible or we should set as mentioned in datasheet?
Thanks & Regards,
As I mentioned earlier, the tables 33, 34 and 35 in the AD9689 datasheet show the list of supported JESD204B modes in full bandwidth mode as well as decimation rates. FsX4 is only supported in full BW mode. You will have to use the link parameters listed in the datasheet and in the memory map for register 0x0570.
If it is only N that you want to change, that is ok. The AD9689 will just zero-stuff the LSBs to match the N' number. CS is set based on the supported modes. So your primary reference should be the supported modes in the tables that i have listed.
In Table 33 of AD9689 datasheet which shows list of JESD204B modes in full bandwidth mode has a configuration where M =2, L = 8, F = 2 , S = 4, HD = 0, N = 8 to 16, N` = 16, CS =0 to 3. In this configuration we have a quiry related to F and S values. If F = 2, in one clock do we get 4 samples of converter 1 in first 4 lanes and 4 samples of converter 2 in next 4 lanes?
Yes. The data formatting will be similar to what you saw in the datasheet figure 2. You can also look at the figure below to see the data formatting.
Retrieving data ...