Wiki

This version (16 Apr 2019 10:39) was approved by lnagy.The Previously approved version (19 Feb 2019 16:37) is available.Diff

AXI_AD9265

The axi_ad9265 IP core can be used to interface the AD9265 analog to digital converter, in LVDS mode.

Features

  • AXI based configuration
  • PRBS monitoring (PN9 and PN23)
  • DC filtering
  • Configurable line delays
  • Vivado compatible

Block Diagram

Configuration Parameter

Name Description Default Value
ID Core ID should be unique for each AD9265 IP in the system 0
DEVICE_TYPE Used to select between Virtex 6 (1) or 7 Series (0) devices 0
ADC_DATAPATH_DISABLE If set, the datapath processing is not generated and output data is taken directly from the AD9265 0
IO_DELAY_GROUP The delay group name which is set for the delay controller “adc_if_delay_group”

Interface

Interface Pin Type Description
adc interface ADC interface signals
adc_clk_in_* input LVDS input clock
adc_data_in_* input[7:0] LVDS input data
adc_or_in_* input LVDS input over range
delay interface Interface used to control the delay lines
delay_clock input Clock used by the IDELAYCTRL. Connect to 200MHz
s axi AXI Slave Memory Map interface
adc fifo FIFO interface for connecting to the DMA
adc_clk output The input clock is passed through an IBUFGDS and a BUFG primitive and adc_clk reults. This is the clock domain that most of the modules of the core run on
adc_rst output Output reset, on the adc_clk domain
adc_enable output Set when the channel is enabled, activated by software
adc_valid output Set when valid data is available on the bus
adc_data output[15:0] Data bus
adc_dovf input Data overflow input, from the DMA
adc_dunf input Data underflow input. Not used

Detailed Architecture


Detailed Description

The top module, axi_ad9265, instantiates:

  • the lvds interface module
  • the channel processing module
  • the ADC common register map
  • the AXI handling interface
  • delay control module

The LVDS interface module, axi_ad9265_if, has as input the lvds signals for clock, data[7:0] and over range. It uses IO block primitives inside of IP to handle the input signals. The input clock is routed to a clock distribution primitive from which it drives all the ADC related processing circuitry. The data signals are passed through an IDELAYE2 so that each line can be delayed independently through the delay controller register map. The IP outputs a data value on every clock cycle, along with the over range signal. The latency between input and output of the interface module is 3 clock cycles.

The data from the interface module is processed by the adc channel module.
The channel module implements:

  • a PRBS monitor
  • data format conversion
  • DC filter
  • the ADC CHANNEL register map

The data analyzed by the PRBS monitor is raw data received from the interface, before being processed in any way. Selection between PN9 and PN23 sequences can be done by programming the REG_CHAN_CNTRL_3 register.

Up_adc_common module implements the ADC COMMON register map, allowing for basic monitoring and control of the ADC.

The delay controller module, up_delay_cntrl, allows the dynamic reconfiguration of the IDELAYE2 blocks. Changing the delay on each individual line helps compensate trace differences between the data lines on the PCB. A calibration procedure can be run on software by changing the delays and monitoring the PRBS sequence.

Register Map

Base (common to all cores)

Click to expand regmap

ADC Common (axi_ad*)

Click to expand regmap

ADC Channel (axi_ad*)

Click to expand regmap

Design Guidelines

The IP was developed part of the AD9265 Native FMC Card Reference Design.

The control of the AD9265 chip is done through a SPI interface, which is needed at system level.

The ADC interface signals must be connected directly to the top file of the design, as IO primitives are part of the IP.

The example design uses a DMA to move the data from the output of the IP to memory.

If the data needs to be processed in HDL before moved to the memory, it can be done at the output of the IP (at system level) or inside of the adc channel module (at IP level).

The example design uses a processor to program all the registers. If no processor is available in your system, you can create your own IP starting from the interface module.

Software Guidelines

The software for this IP can be found as part of the AD9265 Native FMC Card Reference Design at: No-Os Software.
Linux is supported also using ADI Linux repository

References

resources/fpga/docs/axi_ad9265.txt · Last modified: 16 Apr 2019 10:27 by lnagy