5.3.1. AdAcEvse22KwzKitBSP

See also module’s auto-generated reference. The module AdAcEvse22KwzKitBSP is a board support driver for the Analog Devices AD-ACEVSE22KWZ-KIT EVSE reference design.

5.3.1.1. AdAcEvse22KwzKitBSP Quickstart

A typical hardware setup would consist of the AD-ACEVSE22KWZ-KIT and a Raspberry Pi 4 running EVerest with this module. Communication between AD-ACEVSE22KWZ-KIT and the AdAcEvse22KwzKitBSP on the Raspberry Pi 4 is through a 3.3V TTL UART link with a default configuration of 115200 bps 8N1. There is also a GPIO used to reset AD-ACEVSE22KWZ-KIT from EVerest so the firmware is in a known state.

5.3.1.1.1. Hardware Connectivity

By default, AD-ACEVSE22KWZ-KIT supports the Pionix Yak board and Raspberry Pi 4 as host boards running EVerest.

The simplest way to get AD-ACEVSE22KWZ-KIT up and running with EVerest is with a Pionix Yak board. First, you must connect AD-ACEVSE22KWZ-KIT’s P3 to Yak’s J3 using a 10-wire cable. Note that using the 10-wire cable has Yak powered off AD-ACEVSE22KWZ-KIT’s 12V supply.

Next, we need to add the AdAcEvse22KwzKitBSP as an active module inside the configuration YAML file passed to EVerest:

active_modules:
  # ** Other EVerest modules **
  adacevse22kwz_driver:
    telemetry:
      id: 1
    config_module:
      baud_rate: 115200 # default baud rate
      reset_gpio: 27 # Yak reset GPIO pin
      serial_port: /dev/serial0 # Yak UART0 port
    connections: {}
    module: AdAcEvse22KwzKitBSP
    # ** Other EVerest modules **

Next, we need to link our active AdAcEvse22KwzKitBSP to EvseManager to facilitate high-level charging logic. This can be done by adding the following to EvseManager inside the EVerest configuration YAML:

active_modules:
  # ** Other EVerest modules **
  evse_manager:
    config_module:
      # ** Various EvseManager configurations **
    connections:
      bsp:
      - implementation_id: board_support
        module_id: adacevse22kwz_driver
      powermeter_grid_side:
      - implementation_id: powermeter
        module_id: adacevse22kwz_driver
    module: EvseManager
    telemetry:
      id: 1
  # ** Other EVerest modules **

Finally, we can start EVerest. AD-ACEVSE22KWZ-KIT should now be able to communicate with EVerest on the Yak board using AdAcEvse22KwzKitBSP.

AD-ACEVSE22KWZ-KIT can also be run off a Raspberry Pi 4 by using various test points on the AD-ACEVSE22KWZ-KIT instead of the 10-wire cable. These test points can then be connected to Raspberry Pi pins which can operate as a UART link and a standard GPIO:

Purpose

Test Point

RPI Pin

Reset Pin

TP_18

GPIO27

Host TX

TP_28

TX_D0

Host RX

TP_41

RX_D0

Shared ground

Any GND pin

Any GND pin

You can now follow the steps used for configuring EVerest on the Yak board to start EVerest on the Raspberry Pi.

5.3.1.2. Protocol

EVerest can send commands to AD-ACEVSE22KWZ-KIT and AD-ACEVSE22KWZ-KIT publishes data and events back to EVerest. The packets are defined with protobuf to serialize the C structs into a binary representation that is transferred over the serial wire in a stream:

https://developers.google.com/protocol-buffers

To be able to split the stream back into packets all data is encoded using COBS before it is transmitted on the UART:

https://en.wikipedia.org/wiki/Consistent_Overhead_Byte_Stuffing

5.3.1.2.1. COBS

COBS is implemented in adkit_comms/evSerial.cpp. Whenever a new packet was extracted from the stream handlePacket() is called to decode protobuf and generate the corresponding signals. Other parts of the module subscribe to these signals to handle the incoming packets.

For TX linkWrite encodes the packet with COBS and outputs it to the UART.

5.3.1.2.2. Protobuf

The actual packet definitions are located under adkit_comms/protobuf.

adkit.proto contains all messages that can be sent by EVerest and AD-ACEVSE22KWZ-KIT.

Refer to these files for an up-to-date definition as they may change frequently.

To generate the C code nanopb is used:

nanopb_generator -I . -D . *.proto

The output should also be manually copied to AD-ACEVSE22KWZ-KIT Firmware to ensure the same definition is used on both sides when making changes.

5.3.1.2.3. Modes of Operation

AD-ACEVSE22KWZ-KIT board operates in the following two modes:

Hostless mode: AD-ACEVSE22KWZ-KIT acts as a standalone EVSE and will control PWM and relay state without external influence. In this mode, PWM will be enabled immediately upon entering state B1 with the relay closing in state C2 assuming no errors occur. If an error occurs (i.e. RCD trigger, diode short, C1 timeout, etc.), AD-ACEVSE22KWZ-KIT will open the relay and disable PWM until state A1 is reentered where the errors will be cleared.

Host-driven mode: AD-ACEVSE22KWZ-KIT will allow EVerest to influence PWM and relay states. In this mode, PWM will not be enabled until an EVerest PwmDutyCycle command is received. Similarly, the relay will not open in state C2 until an AllowPowerOn message is received. AD-ACEVSE22KWZ-KIT can override relay and PWM state in the event of an error.

By default, the AD-ACEVSE22KWZ-KIT operates in hostless mode until a message is received from the host. Additionally, all outbound messages from AD-ACEVSE22KWZ-KIT are sent irrespective of mode of operation. This enables AD-ACEVSE22KWZ-KIT evaluation without using EVerest.

5.3.1.2.4. Message types

AD-ACEVSE22KWZ-KIT supports the following set of messages:

5.3.1.2.4.1. EVerest to AD-ACEVSE22KWZ-KIT:

AllowPowerOn(bool): Inform AD-ACEVSE22KWZ-KIT that it is allowed to switch on the power relays/contactors to the car on (true) or must switch off now (false). The final decision remains with AD-ACEVSE22KWZ-KIT in case of power on, it should only power on after all other requirements are met (such as RCD current is below limit, car is in CP state C etc). On power off, AD-ACEVSE22KWZ-KIT will switch off immediately.

PwmDutyCycle(uint32): Set AD-ACEVSE22KWZ-KIT PWM state and duty cycle. PWM can be enabled at specific duty cycle by passing a value of 1-10000, where each value corresponds to 0.0001% duty cycle (i.e. 50% duty cycle = 5000 passed value). AD-ACEVSE22KWZ will ignore any duty cycles greater than 5333 as this corresponds to the maximum duty cycle supported. PWM can be disabled by passing a value greater than 10000. PWM state F can be enabled by passing a PWM value of 0.

KeepAlive(Message): EVerest sends this packet to AD-ACEVSE22KWZ-KIT at 1Hz. Currently unused by AD-ACEVSE22KWZ-KIT.

Reset(bool): Reset AD-ACEVSE22KWZ-KIT firmware.

5.3.1.2.5. AD-ACEVSE22KWZ-KIT to EVerest

CpState(enum): Notify EVerest of current CP state (A/B/C/D/E/F). Sent upon state change. AD-ACEVSE22KWZ-KIT currently doesn’t support State D.

RelaisState(bool): Notify EVerest of current relay state. Sent upon relay closing/opening. True corresponds to relay closed and false is sent when relay is open.

PpState(enum): Notify EVerest of current PP state (NC/13A/20A/32A/70A/F). AD-ACEVSE22KWZ-KIT currently doesn’t support PP for maximum output current so 32A is sent by default.

PowerMeter(Message): Sent roughly every second when relay is closed. Contains all data from the ADE9178 power measurement.

ErrorState(Message): Notify EVerest of active errors. Sent when an errors are set/cleared. Each error has an associated boolean value where true corresponds to active error and false corresponds to error not active. Currently, only diode faults, RCD triggered, and overcurrent are supported by AD-ACEVSE22KWZ-KIT.

Telemetry(Message): Telemetry message with cp pwm high and low voltage values. Not currently supported by AD-ACEVSE22KWZ-KIT firmware.

KeepAliveLo(Message): AD-ACEVSE22KWZ-KIT sends this every 3 seconds to keep connection online.

ResetReason(enum): Sent once on boot of the AD-ACEVSE22KWZ-KIT firmware.