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This version (28 Aug 2023 16:13) was approved by Mark Thoren.The Previously approved version (09 Aug 2023 06:29) is available.Diff

EVAL-CN0575-RPIZ User Guide

General Description

The EVAL-CN0575-RPIZ is a 10BASE-T1L MAC/PHY interface with Single Pair Power over Ethernet (SPoE) for development of field devices and applications on a Raspberry Pi platform board. The SPoE powered device (PD) and isolated flyback regulator provide 5 V power to the platform board and attached application circuitry. SPoE Class 12 (8.4 W, 24 V nominal) and Class 13 (7.7 W, 55 V nominal) are supported.

Designed for use on the Raspberry Pi platform, the CN0575 hardware features a 40-pin GPIO header, and follows the same mechanical dimensions as a standard HAT.

To allow board stacking and development of field device applications using Raspberry Pi HATs, an additional GPIO header with extended leads is included with each evaluation board. However, the CN0575 can also be used on its own as a basic temperature sensing field device with remote user input/output via an onboard button and LED.

Evaluation Board Hardware

Primary Side




10BASE-T1L Port (P1 and P2)

The CN0575 evaluation board uses a single port 10BASE-T1L device and can be connected to a link partner using either one of the two physical connectors provided:

  • The P1 terminal block is used for connecting individual wires. Connect the twisted pair to pins 1 and 2, and the shield (if available) to pin 3. Secure the connections by tightening the screws on the terminal block.
  • The P2 port is used for connecting standard IEC 63171-6 cables directly from a 10BASE-T1L-capable controller unit.



PHY Status Indicators (LED0 and LED1)

LED0 and LED1 are the ADIN1110 status indicators, and can be configured to display various activities via the device registers.

By default, LED0 is set to turn on when a link is established and blink when there is activity; while LED1 is disabled. Refer to the LED Control Register in the ADIN1110 data sheet for a full list of available functions.


General Purpose LED and Button (ALERT and TEST)

The EVAL-CN0575-RPIZ evaluation board includes a simple button (TEST) and LED (ALERT) circuit that can be respectively used as a digital input and a general purpose indicator. This circuit is controlled by the Raspberry Pi by default (via GPIO16 and GPIO26), but can alternatively be used with external hardware by changing the appropriate jumper settings (refer to Connecting the General Purpose LED and Button to External Hardware).

The GPIO16 pin is normally pulled high in this circuit, but will read low when the TEST button is pressed.


SPoE PD Power Class Selection (JP1 and JP2)

By default, the LTC9111 SPoE PD controller included in the CN0575 circuit is configured for PD Class 12. If a different PD class is required for the application, the JP1 and JP2 solder jumpers should be reconfigured to match the desired class.

JP1 Shunt Position JP2 Shunt Position PD Class VPD(min) PPD(max)
Across Pins 2 and 3 Across Pins 2 and 3 10 14 V 1.23 W
Across Pins 2 and 3 No Shunt Inserted 11 3.20 W
Across Pins 2 and 3 Across Pins 1 and 2 12 8.40 W
Across Pins 1 and 2 Across Pins 2 and 3 13 35 V 7.70 W
Across Pins 1 and 2 No Shunt Inserted 14 20.0 W
Across Pins 1 and 2 Across Pins 2 and 3 15 52.0 W

The CN0575 was designed and evaluated for PD Classes 12 and 13. However, Classes 10 and 11 may still be usable, depending on the power requirements of the Raspberry Pi model used (and its peripherals).

Warning: Do not use PD Classes 14 and 15. The EVAL-CN0575-RPIZ evaluation board is not designed to handle these higher power specifications.



Secondary Side




ADIN1110 SW Power-Down Enable and SPI Configuration (JP3 to JP5)

The EVAL-CN0575-RPIZ evaluation board uses the default hardware configuration for the PHY specified in the ADIN1110 data sheet. If a different operating mode is required for the application, the ADIN1110 should first be placed into software power-down and then configured appropriately via the device registers.

Refer to the table below on setting the JP3 jumper to enable/disable the software power-down feature:

JP3 Setting Software Power-Down Configuration
Open PHY enters software PD mode after a reset operation (Default).
Shorted PHY does not enter software PD mode after a reset operation.


The ADIN1110 supports both generic SPI and the OPEN Alliance SPI protocol in its communication. Refer to the table below on setting JP4 and JP5 to select the SPI protocol:

JP4 Setting JP5 Setting SPI Protocol
Open Open OPEN Alliance with Protection
Open Shorted OPEN Alliance without Protection
Shorted Open Generic SPI with 8-bit CRC
Shorted Shorted Generic SPI without 8-bit CRC (Default)


ADT75 I²C Bus Address Selection (JP6 to JP8)

The I²C bus address of the onboard ADT75 temperature sensor is dependent on the settings of the JP13, JP14, and JP15 solder jumpers. Note: The CN0575 device tree overlay in ADI Kuiper Linux has the temperature sensor I²C address set to the default 0x48.
If there is a need to reassign the ADT75 address, refer to the following table:

Jumper Settings I2C Bus Address
JP6 JP7 JP8
B B B 0x48 (Default)
B B A 0X49
B A B 0X4A
B A A 0X4B
A B B 0X4C
A B A 0X4D
A A B 0X4E
A A A 0X4F


Optional GPIO Pins (JP9 to JP13)

By default, some functions of the EVAL-CN0575-RPIZ are connected to various GPIO pins of the Raspberry Pi. If these features will not be used in the application, the corresponding jumpers can be removed - doing this will allow these GPIO pins to be used for other external hardware.



Jumper GPIO Circuit Function Description
JP9 GPIO27 ADIN1110 Reset This an active low ADIN1110 input that resets the part when held low for >10 μs.
JP10 GPIO22 ADIN1110 Link Status Output This is an active high ADIN1110 output that indicates whether a valid 10BASE-T1L link has been established.
JP11 GPIO23 Time Stamp Capture Signal Assert this pin to timestamp the latest incoming frame received by the ADIN1110. The captured timestamp will be stored in the TS_EXT_CAPT0 and TS_EXT_CAPT1 registers.
JP12 GPIO24 Time Stamp Timer Signal This pin is connected to the TS_TIMER pin of the ADIN1110. When the TS_TIMER output is enabled in the device registers, a waveform with high and low times set by the TS_TIMER_HI and TS_TIMER_LO registers is generated.
JP13 GPIO6 Overtemperature Indicator This pin is asserted when the onboard ADT75 temperature sensor is put into one-shot mode and the temperature measurement exceeds TOS (80 °C; default value). By default, the indicator is active low and will only be de-asserted when the temperature drops below THYST (75 °C; default value). The temperature sensor can be reprogrammed to change the polarity of this pin, the de-assertion requirement, and the values of TOS and THYST.


General Purpose LED and Button Connections (JP14 and JP15)

While normally functioning as a digital input and general purpose indicator respectively, the TEST button and ALERT LED can alternatively be used for external applications by changing the settings of the appropriate jumpers. JP14 is used to set the button connection, while JP15 is used to set the LED connection.

JP14 Setting Connection
Open TEST button is connected to GPIO16 of the Raspberry Pi (Default).
Shorted TEST button is not connected to the Raspberry Pi.


JP15 Setting Connection
Open ALERT LED is connected to GPIO26 of the Raspberry Pi (Default).
Shorted ALERT LED is not connected to the Raspberry Pi.


External hardware can be connected to the TEST button and ALERT LED using the BTN_IO and LED_IO test points, respectively.



System Setup

Required Equipment

Hardware

  • EVAL-CN0575-RPIZ Circuit Evaluation Board
  • Raspberry Pi Model 3B (or higher)
  • Micro-SD Card for Raspberry Pi
  • 10BASE-T1L media converter, either:
    • EVAL-ADIN1100EBZ Product Evaluation Board
    • Other 10BASE-T to 10BASE-T1L media converter
    • USB to 10BASE-T1L
  • Power Source, either:
    • 10BASE-T1L Power Coupling Network Board w/ SPoE PSE or DC Power Supply
    • USB-C or USB-Micro 5V wall adapter (plugged directly into Raspberry Pi)
  • Host Windows, Linux, or Mac computer

Software

Documentation


Block Diagram

Setup with SPoE via PSE or DC Power Supply:

Power coupling boards compatible with the EVAL-ADIN1100 for various SPoE classes and droop levels are in development. Alternatively, use a media converter that supports SPoE PSE functionality.
Refer to the LTC4296-1 datasheet for example coupling networks.





Setup without SPoE (USB-Powered Application):





Software Setup

Downloading and Flashing the Micro-SD Card

To use the EVAL-CN0575-RPIZ with the Raspberry Pi, the micro-SD card should be preloaded with Analog Devices Kuiper Linux, a distribution based on Raspbian from the Raspberry Pi Foundation that incorporates Linux drivers for ADI products as well as tools and other software products.

Complete instructions, including where to download the SD card image, how to write it to the micro-SD card, and how to configure the system are provided at Kuiper Images.



Configuring the Micro-SD Card

The Linux kernel requires a matching device tree overlay to identify the devices on the CN0575. The overlay file is included with the Analog Devices Kuiper Linux and simply needs to be enabled.

To do this, follow the Hardware Configuration procedure under Configuring the SD Card for Raspberry Pi Projects in the Kuiper Images page. Enable the CN0575 overlay by adding the following line to config.txt:

dtoverlay=rpi-cn0575


Save the file and reboot the system by entering the following command in the console:

analog@analog:~$ sudo reboot


Determining the IP Address of the CN0575

Follow the below procedure to determine the IP address assigned by the Raspberry Pi to the EVAL-CN0575-RPIZ:

  1. Complete the hardware setup described in the Basic Operation section.
  2. Remove the Ethernet cable from the EVAL-ADIN1100EBZ evaluation board and connect it directly to the Raspberry Pi.
  3. Run PuTTY and connect to the Raspberry Pi via SSH. For the Host Name (or IP address), use analog.local.
  4. Enter the command ifconfig in the console.
  5. The IP address of the EVAL-CN0575-RPIZ board will be listed as inet under adin1110-0. In the example below, the IP address is 169.254.158.120.



Basic Operation




To establish a 10BASE-T1L connection to a Raspberry Pi using the EVAL-CN0575-RPIZ evaluation board and run a basic temperature measurement example, follow the below procedure:

  1. Ensure that the jumpers and switches of the EVAL-ADIN1100EBZ are configured to the default settings.
  2. Insert the micro-SD card into its slot on the Raspberry Pi.
  3. Connect the EVAL-CN0575-RPIZ circuit evaluation board to the Raspberry Pi GPIO header.
  4. Using an Ethernet cable, connect P5 on the EVAL-ADIN1100EBZ evaluation board to an RJ-45 port on the computer.
  5. Using a micro-USB cable, connect P401 on the EVAL-ADIN1100EBZ evaluation board to a USB port on the computer.
  6. Operation with SPoE PSE or DC Power Supply: (Skip to step 7 if using a USB wall adapter instead)
    • Set the output of the PSE or DC power supply to either 24V (Class 12) or 55V (Class 13), depending on the settings of JP1 and JP2 on the CN0575 board.
    • Using wires, connect the output of an SPoE power coupler to the P1 terminal block on the EVAL-CN0575-RPIZ circuit evaluation board. Similarly, connect the data input of the power coupler to the P101 terminal block on the EVAL-ADIN1100EBZ evaluation board.
    • Connect the output of the SPoE PSE (or DC power supply) to the power input of the SPoE power coupler and enable it.
  7. Operation without SPoE (USB-Powered Application):
    • Using wires, connect the P1 terminal block on the EVAL-CN0575-RPIZ circuit evaluation board to the P101 terminal block on the EVAL-ADIN1100EBZ evaluation board.
    • Connect the USB wall adapter to the power connector on the Raspberry Pi.
  8. Wait for the LINK LED on the EVAL-CN0575-RPIZ circuit evaluation board and the LED_0 LED on the EVAL-ADIN1100EBZ evaluation board to turn on and start blinking at the same time. This indicates that a 10BASE-T1L link has been established.
  9. On the host PC, run PuTTY and connect to the Raspberry Pi using the EVAL-CN0575-RPIZ IP address.
  10. In the Raspberry Pi console, navigate to the examples directory of pyadi-iio. Run the temperature measurement example by entering the following command:


.../pyadi-iio/examples $ sudo python lm75_example.py




More Complete Example with Digital I/O

A more complete example that blinks the onboard LED and reads the push button is also provided. Note that this script can be run either directly on the Raspberry Pi, or remotely from a host computer.
From the Raspberry Pi command line, run:

.../pyadi-iio/examples $ sudo python cn0575_example.py

Or from PowerShell on a Windows remote host, run:

...\pyadi-iio\examples> python .\cn0575_example.py

The script will attempt to automatically locate the CN0575 over the network connection. The CN0575's IIO context URI can also be passed to the script explicitly, where www.xxx.yyy.zzz is the board's IP address:

C:\temp\pyadi-iio\examples> python .\cn0575_example.py ip:www.xxx.yyy.zzz

Typical output is shown below:



Errata

The first batch of EVAL-CN0575-RPIZ circuit evaluation boards that was produced mistakenly have a 50V capacitor installed on C16. This voltage rating is insufficient for Class 13 operation where the SPoE voltage can be as high as 58 V (and potentially even more during surge events).

These boards can be identified by the last three letters on C16 (HTH, shown right). If you have one of these and intend to use it in a Class 13 application, either replace C16 with a 100 V capacitor (preferred; this is the same rating used in later batches of the EVAL-CN0575-RPIZ), or simply desolder it and leave it empty.



Schematic, PCB Layout, Bill of Materials

EVAL-CN0575-RPIZ Design & Integration Files

  • Schematics
  • PCB Layout
  • Bill of Materials
  • Allegro Project



Hardware Registration

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End of Document

resources/eval/user-guides/circuits-from-the-lab/cn0575.txt · Last modified: 28 Aug 2023 16:13 by Mark Thoren