|
| 1 | +??? note "This ESP32 only feature is included in tasmota32 binaries" |
| 2 | + |
| 3 | + When [compiling your build](Compile-your-build) add the following to `user_config_override.h`: |
| 4 | + ```arduino |
| 5 | + #ifndef USE_ESP32_TWAI |
| 6 | + #define USE_ESP32_TWAI // Add support for TWAI/CAN interface (+7k code) |
| 7 | + #endif |
| 8 | + ``` |
| 9 | + |
| 10 | +## What is TWAI? |
| 11 | + |
| 12 | +[Two-Wire Automotive Interface](https://https://docs.espressif.com/projects/esp-idf/en/stable/esp32/api-reference/peripherals/twai.html) (TWAI) or Controller Area Network (CAN) is a real-time serial communication protocol suited for automotive and industrial applications. It is compatible with ISO11898-1 Classical frames, thus can support Standard Frame Format (11-bit ID) and Extended Frame Format (29-bit ID). |
| 13 | + |
| 14 | +The ESP32 series contains 1 to 3 TWAI controller(s) that can be configured to communicate on a TWAI bus via an external transceiver. |
| 15 | + |
| 16 | +??? warning "The TWAI controller is not compatible with ISO11898-1 FD Format frames, and will interpret such frames as errors." |
| 17 | + |
| 18 | +## Hardware needed |
| 19 | + |
| 20 | +TWAI needs only 2 GPIOs connected to an external tranceiver like [M5 Unit CAN](https://docs.m5stack.com/en/unit/can) with isolation or [M5 Mini CAN Unit](https://docs.m5stack.com/en/unit/Unit-Mini%20CAN) without isolation. |
| 21 | + |
| 22 | + |
| 23 | +## Configuration |
| 24 | + |
| 25 | +Parameters to configure the driver need to be entered using a berry script. See examples below. |
| 26 | + |
| 27 | +The following table shows the supported Interface Speed. |
| 28 | + |
| 29 | +Code|Speed |
| 30 | +:---|:--- |
| 31 | +0|25Kbit/s |
| 32 | +1|50Kbit/s |
| 33 | +2|100Kbit/s |
| 34 | +3|125Kbit/s |
| 35 | +4|250Kbit/s |
| 36 | +5|500Kbit/s |
| 37 | +6|800Kbit/s |
| 38 | +7|1Mbit/s |
| 39 | + |
| 40 | +The following table shows the supported Operating Modes. |
| 41 | + |
| 42 | +Code|Mode |
| 43 | +:---|:--- |
| 44 | +0|Normal Mode |
| 45 | +1|No Ack Mode |
| 46 | +2|Listen Only Mode |
| 47 | + |
| 48 | +## Command |
| 49 | + |
| 50 | +Without a berry configuration and decoding script the driver is configured for 100Kbit/s and Normal Mode. The received data is output as logging messages in debug log level 3. |
| 51 | + |
| 52 | +The amount of CAN data can be very high AND decoding this data is specific to every implementation. Therefor it was decided to implement both functions as a berry script. See below for examples. |
| 53 | + |
| 54 | +The driver has one command for sending data. |
| 55 | + |
| 56 | +Command|Parameters |
| 57 | +:---|:--- |
| 58 | +TwaiSend<bus\><a class="cmnd" id="dalisend"></a>|Send zero or up to eigth data bytes to an 11-bit or 29-bit identifier.<br><br>`<id>` = Send no data to identifier where identifier is an 11-bit id if bit 31 is 0, ex. `0x284`. If bit 31 is 1 then a 29-bit id is expected, ex. `0x80001234`.<br>`<id>,<byte1>[..,<byte8>]` = Send one or more data bytes.<br>`{"ID":0x284,"DATA":[0x44,3,0x1E,0xFF]}` = Alternative using JSON sending four data bytes. |
| 59 | + |
| 60 | +## Example |
| 61 | + |
| 62 | +### Basic configuration |
| 63 | + |
| 64 | +A minimal berry script should look like this: |
| 65 | +``` |
| 66 | +class twai_cls |
| 67 | + var active # (bool) |
| 68 | + var twai_speed, twai_mode # (int, int) |
| 69 | +
|
| 70 | + def init() |
| 71 | + self.twai_speed = 4 # 0 = 25K, 1 = 50K, 2 = 100K, 3 = 125K, 4 = 250K, 5 = 500K, 6 = 800K, 7 = 1Mbits |
| 72 | + self.twai_mode = 2 # 0 = TWAI_MODE_NORMAL, 1 = TWAI_MODE_NO_ACK, 2 = TWAI_MODE_LISTEN_ONLY |
| 73 | + self.active = 0 |
| 74 | + end |
| 75 | +
|
| 76 | + #---------------------------------------------------------------------------------------------- |
| 77 | + Allow TWAI driver configuration on restart (if this file is installed by preinit.be) |
| 78 | + ----------------------------------------------------------------------------------------------# |
| 79 | + def config(bus) # This function name (config) is called by the TWAI driver! |
| 80 | + return self.twai_mode << 3 | self.twai_speed # Initial configure TWAI driver |
| 81 | + end |
| 82 | +
|
| 83 | + #---------------------------------------------------------------------------------------------- |
| 84 | + This example decodes nothing but allows for the driver to show message logging in log level 4 |
| 85 | + ----------------------------------------------------------------------------------------------# |
| 86 | + def decode(param, ident, data1, data2) # This function name (decode) is called by the TWAI driver! |
| 87 | + var bus = param & 0xF # Bus number (1..3) |
| 88 | + var len = param >> 4 & 0xF # Number of data bytes (0..8) |
| 89 | + var extended = ident >> 31 & 0x1 # Extended identifier flag (0..1) |
| 90 | + var id = ident & 0x1fffffff |
| 91 | +
|
| 92 | +
|
| 93 | + self.active = 1 # At least one valid decode |
| 94 | + end |
| 95 | +end |
| 96 | +
|
| 97 | +twai = twai_cls() # This class name (twai) is used by the TWAI driver! |
| 98 | +tasmota.add_driver(twai) |
| 99 | +``` |
| 100 | +Save the file as `twai.be` and add a line `load('twai.be')` to file `preinit.be`. This will execute the file at restart and prepare the driver for 250Kbit/s and Listen Only Mode. |
| 101 | + |
| 102 | +### Remeha Calenta Ace sniffer to Domoticz |
| 103 | + |
| 104 | +<img alt="Remeha" src="../_media/Remeha1.jpg" style="margin:10px;float:right;width:20em"> </img> |
| 105 | +The Remeha boiler provides a RJ12 connector for a Service Tool. The communication between the boiler and the Service Tool takes place using CAN-bus in 11-bit identifier mode. A dongle consisting of a M5 Mini CAN Unit and a M5Atom (ESP32/ESP32S3) or M5Nano (ESP32C6) with Tasmota can be used as sniffer sending important data to a Home Automation tool like Domoticz. |
| 106 | + |
| 107 | +The RJ12 6-pin usage as shown from the front of the boiler |
| 108 | + |
| 109 | +Pin number:|1|2|3|4|5|6 |
| 110 | +:-|:-|:-|:-|:-|:-|:- |
| 111 | +Remeha Ace RJ12|24V|-|Gnd|-|Tx|Rx |
| 112 | +M5 Mini CAN |HV| |G| |L|H |
| 113 | + |
| 114 | +To make the M5 Mini CAN Unit compliant with the CAN-bus standard you'll need to remove the internal 120 Ohm resistor as the Remeha L-Bus is already terminated with two 120 Ohm resistors. As an alternative you can use the M5 Unit CAN which has no internal 120 Ohm termination resistor. In that case you'll need to power the Atom or Nano externally with a USB power supply as the CAN-bus is isolated. |
| 115 | + |
| 116 | +This berry class supports a Remeha Calenta Ace boiler sending some data to Domoticz home automation for logging. |
| 117 | +``` |
| 118 | +class twai_cls |
| 119 | + var active, pressure_next # (bool, bool) |
| 120 | + var twai_speed, twai_mode # (int, int) |
| 121 | + var am012_status, am014_substatus, am024_power # (int, int, int) |
| 122 | + var dz_am012_status, dz_am014_substatus # (int, int) |
| 123 | + var pressure, setpoint, flow_temp # (float, float, float) |
| 124 | + var dz_pressure, dz_flow_temp # (float, float) |
| 125 | +
|
| 126 | + def init() |
| 127 | + self.twai_speed = 7 # 0 = 25K, 1 = 50K, 2 = 100K, 3 = 125K, 4 = 250K, 5 = 500K, 6 = 800K, 7 = 1Mbits |
| 128 | + self.twai_mode = 2 # 0 = TWAI_MODE_NORMAL, 1 = TWAI_MODE_NO_ACK, 2 = TWAI_MODE_LISTEN_ONLY |
| 129 | + self.active = 0 |
| 130 | + self.am012_status = 0 |
| 131 | + self.am014_substatus = 0 |
| 132 | + self.dz_am012_status = 0 |
| 133 | + self.dz_am014_substatus = 0 |
| 134 | + self.am024_power = 0 |
| 135 | + self.pressure_next = 0 |
| 136 | + self.pressure = 0 |
| 137 | + self.dz_pressure = 0 |
| 138 | + self.setpoint = 0 |
| 139 | + self.flow_temp = 0 |
| 140 | + self.dz_flow_temp = 0 |
| 141 | + end |
| 142 | +
|
| 143 | + #---------------------------------------------------------------------------------------------- |
| 144 | + Allow TWAI driver configuration on restart (if this file is installed by preinit.be) |
| 145 | + ----------------------------------------------------------------------------------------------# |
| 146 | + def config(bus) |
| 147 | +# if bus != 1 return nil end # Exit if not my bus |
| 148 | + return self.twai_mode << 3 | self.twai_speed # Initial configure TWAI driver |
| 149 | + end |
| 150 | +
|
| 151 | + #---------------------------------------------------------------------------------------------- |
| 152 | + This example decodes Remeha Calenta Ace CAN-bus messages and sends it to predefined Domoticz idx |
| 153 | + ----------------------------------------------------------------------------------------------# |
| 154 | + def decode(param, ident, data1, data2) |
| 155 | + var bus = param & 0xF # Bus number (1..3) |
| 156 | +# if bus != 1 return nil end # Exit if not my bus |
| 157 | + var len = param >> 4 & 0xF # Number of data bytes (0..8) |
| 158 | + var extended = ident >> 31 & 0x1 # Extended identifier flag (0..1) |
| 159 | + if extended == 1 return nil end # Remeha uses 11-bit Standard Frame Format |
| 160 | + var id = ident & 0x1fffffff |
| 161 | + if id == 0x076 # Incremental counter from 0 to 255 |
| 162 | +# tasmota.log(f"RMH: 0x{id:03x} Count {data1}", 3) |
| 163 | +# elif id == 0x080 # Heartbeat every second |
| 164 | + elif id == 0x100 # Date and Time |
| 165 | + var epoch = 441763200 + (data2 * 24 * 60 * 60) + (data1 / 1000) |
| 166 | +# tasmota.log(f"RMH: 0x{id:03x} Time {tasmota.time_str(epoch)}", 3) |
| 167 | + elif id == 0x1C1 # Many different data1/2 |
| 168 | + if data1 & 0x00ffffff == 0x503f41 # Next time it's pressure |
| 169 | + self.pressure_next = 1 |
| 170 | + elif self.pressure_next == 1 |
| 171 | + self.pressure = (data2 & 0xff00)/2560.0 # This must be pressure |
| 172 | + self.pressure_next = 0 |
| 173 | + end |
| 174 | + elif id == 0x382 |
| 175 | + self.am024_power = data1 & 0xff # Relative power |
| 176 | + self.setpoint = (data1 & 0xffff00)/25600.0 # Setpoint |
| 177 | +# tasmota.log(f"RMH: 0x{id:03x} Busy {self.am024_power}%, Setpoint {self.setpoint}", 3) |
| 178 | + elif id == 0x282 |
| 179 | + self.flow_temp = (data1 & 0xffff00)/25600.0 |
| 180 | +# tasmota.log(f"RMH: 0x{id:03x} DHW temp {self.flow_temp}", 3) |
| 181 | + elif id == 0x481 # Status information |
| 182 | + self.am012_status = data1 & 0xff |
| 183 | + self.am014_substatus = (data1 & 0xff00)/256 |
| 184 | + else |
| 185 | + return |
| 186 | + end |
| 187 | + self.active = 1 # At least one valid decode |
| 188 | + end |
| 189 | +
|
| 190 | + #---------------------------------------------------------------------------------------------- |
| 191 | + Add sensor value to teleperiod |
| 192 | + ----------------------------------------------------------------------------------------------# |
| 193 | + def json_append() |
| 194 | + if !self.active return nil end # Exit if never decoded something |
| 195 | + import string |
| 196 | + var msg = string.format(",\"Calenta\":{\"AM012\":%i,\"AM014\":%i,\"Pressure\":%.1f,\"Setpoint\":%.1f,\"Flow\":%.1f}", |
| 197 | + self.am012_status, self.am014_substatus, self.pressure, self.setpoint, self.flow_temp) |
| 198 | + tasmota.response_append(msg) |
| 199 | + end |
| 200 | +
|
| 201 | + #---------------------------------------------------------------------------------------------- |
| 202 | + Perform action just after teleperiod (not used) |
| 203 | + ----------------------------------------------------------------------------------------------# |
| 204 | +# def after_teleperiod() |
| 205 | + #---------------------------------------------------------------------------------------------- |
| 206 | + Perform action every second |
| 207 | +
|
| 208 | + As many datagrams can occur sending at teleperiod time takes too long |
| 209 | + Also only send if changed to reduce TWAI wait time |
| 210 | + ----------------------------------------------------------------------------------------------# |
| 211 | + def every_second() |
| 212 | + if self.dz_pressure != self.pressure |
| 213 | + tasmota.cmd('_DzSend1 523,' .. self.pressure) # Send pressure to Domoticz |
| 214 | + end |
| 215 | + self.dz_pressure = self.pressure |
| 216 | +
|
| 217 | + if self.dz_flow_temp != self.flow_temp |
| 218 | + tasmota.cmd('_DzSend1 526,' .. self.flow_temp) # Send flow temp to Domoticz |
| 219 | + end |
| 220 | + self.dz_flow_temp = self.flow_temp |
| 221 | +
|
| 222 | + if self.dz_am012_status != self.am012_status |
| 223 | + tasmota.cmd('_DzSend1 536,' .. self.am012_status) # Send status to Domoticz |
| 224 | + end |
| 225 | + self.dz_am012_status = self.am012_status |
| 226 | +
|
| 227 | + if self.dz_am014_substatus != self.am014_substatus |
| 228 | + tasmota.cmd('_DzSend1 537,' .. self.am014_substatus) # Send substatus to Domoticz |
| 229 | + end |
| 230 | + self.dz_am014_substatus = self.am014_substatus |
| 231 | + end |
| 232 | +
|
| 233 | + #---------------------------------------------------------------------------------------------- |
| 234 | + Display sensor value in the web UI |
| 235 | + ----------------------------------------------------------------------------------------------# |
| 236 | + def web_sensor() |
| 237 | + if !self.active return nil end # Exit if never decoded something |
| 238 | + import string |
| 239 | + var msg = string.format("{s}AM012/AM014 State{m}%i/%i{e}".. |
| 240 | + "{s}AM024 Relative Power{m}%i %%{e}".. |
| 241 | + "{s}Pressure{m}%.1f{e}".. |
| 242 | + "{s}Setpoint Temperature{m}%.1f{e}".. |
| 243 | + "{s}Flow Temperature{m}%.1f{e}", |
| 244 | + self.am012_status, self.am014_substatus, self.am024_power, self.pressure, self.setpoint, self.flow_temp) |
| 245 | + tasmota.web_send_decimal(msg) |
| 246 | + end |
| 247 | +end |
| 248 | +
|
| 249 | +twai = twai_cls() |
| 250 | +tasmota.add_driver(twai) |
| 251 | +``` |
| 252 | +Save the file as `twai.be` and add a line `load('twai.be')` to file `preinit.be`. This will execute the file a restart and prepare the driver for 1Mbit/s and Listen Only Mode. |
| 253 | + |
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