CN0363 HDL project

Overview

The EVAL-CN0363-PMDZ is a dual channel colorimeter featuring a modulated light source transmitter, programmable gain transimpedance amplifiers on each channel, and a very low noise, 24-bit sigma delta ADC. The output of the ADC connects via a standard PMOD connector to a FPGA. The FPGA takes the sampled data from the ADC and implements a synchronous detection algorithm. By using modulated light and digital synchronous detection, rather than a constant (dc) source, the system strongly rejects any noise sources at frequencies other than the modulation frequency, providing excellent accuracy.

The dual channel circuit measures the ratio of light absorbed by the liquids in the sample and reference containers at three different wavelengths. This forms the basis of many chemical analysis and environmental monitoring instruments used to measure concentrations and characterize materials through absorption spectroscopy.

The EVAL-CN0363-PMDZ HDL reference design is based on the Analog Devices base reference design for the ZED board. In addition to the base reference design EVAL-CN0363-PMDZ HDL reference design implements function blocks to communicate over a SPI bus with the AD7175-2 Sigma-Delta ADC to configure it and receive the raw ADC data as well a configure the AD5201 digital potentiometer. The data received from the ADC is passed to a processing pipeline which performs a digital synchronous detector and finally write the data to system memory using a DMA. The HDL reference design is also responsible for generating the LED excitation signal. A simplified functional block diagram of the system is given below.

Supported boards

• EVAL-CN0363-PMDZ

Supported devices

• CN0363

• AD7175-2

• AD5201

Supported carriers

• ZedBoard on PMOD connector

Block design

Block diagram

The data path and clock domains are depicted in the below diagram:

CPU/Memory interconnects addresses

The addresses are dependent on the architecture of the FPGA, having an offset added to the base address from HDL (see more at HDL Architecture).

Instance	Address
axi_adc	0x43C0_0000
spi_cn0363_axi_regmap	0x44A0_0000
axi_dma	0x44A3_0000

I2C connections

I2C type	I2C manager instance	Alias	Address	I2C subordinate
PL	iic_fmc	axi_iic_fmc	0x4162_0000	—
PL	iic_main	axi_iic_main	0x4160_0000	—

SPI connections

SPI type	SPI manager instance	SPI subordinate	CS
PL	axi_spi_engine	cn0363	0

GPIOs

The Software GPIO number is calculated as follows:

• Zynq-7000: if PS7 is used, then offset is 54

GPIO signal	Direction	HDL GPIO EMIO	Software GPIO
	(from FPGA view)		Zynq-7000
spi_sdi	IN	34	88
gain1_o	OUT	33	87
gain0_o	OUT	32	86

Interrupts

Below are the Programmable Logic interrupts used in this project.

Instance name	HDL	Linux Zynq	Actual Zynq
axi_dma	13	57	89
spi	12	56	88

Building the HDL project

The design is built upon ADI’s generic HDL reference design framework. ADI does not distribute the bit/elf files of these projects so they must be built from the sources available here. To get the source you must clone the HDL repository, and then build the project as follows:

Linux/Cygwin/WSL

user@analog:~$ cd hdl/projects/cn0363/zed
user@analog:~/hdl/projects/cn0363/zed$ make

A more comprehensive build guide can be found in the Build an HDL project user guide.

Resources

Systems related

Here you can find the quick start guides available for these evaluation boards:

• [Wiki] EVAL-CN0363-PMDZ user guide

• [Wiki] EVAL-CN0363-PMDZ Zed quick start guide

• [Wiki] CN0363 Colorimeter Application user guide

Hardware related

• Product datasheets:

  • CN0363

  • AD7175-2

  • AD5201

  • AD8615

  • ADG819

  • ADA4528-1

• EVAL-CN0363-PMDZ Introduction

• EVAL-CN0363-PMDZ Hardware

• EVAL-CN0363-PMDZ Hardware Setup

HDL related

• CN0363_PMDZ HDL project source code

• [Wiki] CN0540 HDL project documentation

IP name	Source code link	Documentation link
AXI_DMAC	library/axi_dmac	here
AXI_GENERIC_ADC	library/axi_generic_adc	—
AXI_HDMI_TX	library/axi_hdmi_tx	[Wiki]
AXI_I2S_ADI	library/axi_i2s_adi	—
AXI_SPDIF_TX	library/axi_spdif_tx	—
AXI_SYSID	library/axi_sysid	[Wiki]
CN0363_DMA_SEQUENCER	library/cn0363/cn0363_dma_sequencer	[Wiki]
CN0363_PHASE_DATA_SYNC	library/cn0363/cn0363_phase_data_sync	[Wiki]
CORDIC_DEMOD	library/cordic_demod	—
AXI_SPI_ENGINE	library/spi_engine/axi_spi_engine	here
SPI_ENGINE_EXECUTION	library/spi_engine/spi_engine_execution	here
SPI_ENGINE_INTERCONNECT	library/spi_engine/spi_engine_interconnect	here
SPI_ENGINE_OFFLOAD	library/spi_engine/spi_engine_offload	here
SYSID_ROM	library/sysid_rom	[Wiki]
UTIL_AXIS_RESIZE	library/util_axis_resize	—
UTIL_I2C-MIXER	library/util_i2c_mixer	—
UTIL_SIGMA_DELTA_SPI	library/util_sigma_delta_spi	[Wiki]

• SPI Engine Framework documentation

Software related

• CN0363 Linux driver source code

• CN0363 Linux Driver [Wiki]

More information

• ADI HDL User guide

Support

Analog Devices, Inc. will provide limited online support for anyone using the reference design with ADI components via the EngineerZone FPGA reference designs forum.

For questions regarding the ADI Linux device drivers, device trees, etc. from our Linux GitHub repository, the team will offer support on the EngineerZone Linux software drivers forum.

For questions concerning the ADI No-OS drivers, from our No-OS GitHub repository, the team will offer support on the EngineerZone microcontroller No-OS drivers forum.

It should be noted, that the older the tools’ versions and release branches are, the lower the chances to receive support from ADI engineers.