10-18-2013 03:15 AM
Hi i am using kintex_7 FPGA, and i instantiated AXI-XADC in EDK connected with microblaze.
I am using ADC in continuos mode for external analog inputs(VAUX) only. For that i'm writing config.reg#0 as 0x8410 and other config. registers i am writing 0x0000. But when i,m reading all the VAUX registers showing zeros only, means i,m not getting conversion with XADC.
I am refering ug480 and pg19 guides.
PLEASE do help to get converted value in the registers.
10-20-2013 04:40 AM - edited 10-20-2013 11:44 AM
Your setting for config reg0 is correct - but you must also tell the XADC that it should operate in 'single channel mode' - this is set by config reg1 - bits 15:12 and are referred to as the 'sequence mode'.
You mentioned that all other registers are 0 - so this means sequence mode is 0x0, which is 'default mode'. Default mode only looks at the internal sensors, so this is why you are not seeing any data on the Vaux channel.
To put the XADC in 'single channel mode', set these bits to 0x3.
In general if you want to 'debug' the XADC, looking at the outputs 'CHANNEL' and 'EOC' is very useful:
CHANNEL will always have the last channel converted (so should be 0x10 in your case), and 'EOC' pulses when there is new data available for that channel.
Another thing to be aware of when using the VAUX inputs is to make sure they are connected to the top-level ports of your design - as this is how you declare to the SW that these inputs are to be used as analog inputs.
Hope this helps,
10-21-2013 04:36 AM
Hi jmcgrath thank you very much for your reply,
Now i am able to see the data in registers.
But one more issue is, when i am opening chipscope pro and see the value of Vaux, then only i am getting converted result in registers in XMD command prompt..
IF i am directly configuring the registers and reading the value of registers through XMD command prompt i am getting 0's only. Then immediately when i open chipscope and monitor the Vaux then i am getting the hex value in my registers through XMD command prompt.
Please help me to read the registers directly with out depending on chip scope tool
can any body please tell me why it is happening like this....
Thank you in advance.
10-21-2013 05:30 AM
Later on i found that i am able to read the HEX values in XMD command prompt as well as in chip scope only when i am selecting the Vaux signals to monitor in chip scope. At that time chipscope is enabling the external VAUX signals.
But i have to enable the VAUX only from XMD command prompt.
In XMD command prompt i tried to enable VAUX signals by writing 0x1 in VCCAUX register(base_addr+0x208), but it is not happening.
so please help me to enable external Vaux signals from XMD command prompt.
Thank you in advance.....