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WIO Firmware


This project is targeted to the ESP8266, ESP32 and RP20401) platforms.
The source code is only available to be able to flash it on the target device if no other method is possible.
Forking or manipulating the source code is NOT allowed and is protected by copyright.

It can be used as:

  • Wireless Throttle

or as wireless I/O with:

and one of the following extra functions:

  1. LED control WS2812
  2. 4 Servos
  3. 2 RC522 readers
  4. DCC Generator
  5. Mobile PWM, direction and lights

and one of the following options:

  • ID12LA 125kHz RFID reader on RX
  • RailCom reader on RX

Supported Boards

  • Raspberry Pi Pico W → recommended
  • Lolin D1 Mini
  • Lolin D32
  • ESP32 Dev Module
  • ESP32 D1 Mini

Used Pins

Check the pin mapping in Pins.cpp:

  • Pins.cpp



Exhibition used WiFi channels...

  1. The Rocrail server must run on a PC which does not automatically suspend or sleep in case of no user activity. Check the energy setting to prevent communication loss.
  2. The used WiFi Router should be state of the art; Only use maintained hardware.
  3. Make sure the SSID is not visible to prevent extra public traffic.
Using WIO is at your own risk.
Peter Giling and Robert Jan Versluis can not be held responsible for any damage or problems by using the proposed hard- and firmware.
The published hardware are prototypes, are incomplete and not ready for release.
Only original GCA Kits are supported.

Arduino IDE

Prepare the Arduino IDE with the following boards and libraries:

Boards Manager

Add in the preference dialog to "Additional Boards Manager" the following URL's:

And install the ESP8266 and ESP32 Boards.

Board selection

LOLIN(WEMOS)D1 R2 & mini


ESP8266 & ESP32

  • ESP8266 (Board Manager)
  • Adafruit NeoPixel (WS2812)
  • RotaryEncoder
  • MFRC522 (RC522)
  • Servo
  • ArduinoOTA
  • mcp_can
  • SparkFun APDS9960 RGB and Gesture Sensor
    Line 198 in the Arduino/libraries/SparkFun_APDS9960.h must be changed from NA_STATE into NO_STATE because it conflicts with the WiFi RP2040 library. This Enum value ist not used in the Arduino/libraries/SparkFun_APDS9960.cpp. (implementation)


To compile WIO

  • Board esp32 → 2.0.17

ESP32CAN Modifications
The xSemaphoreTake should timeout after 500ms instead of wait for ever.
Replace portMAX_DELAY with 500, and return the rc of the xSemaphoreTake function instead of zero. (CAN.c)

int CAN_write_frame(const CAN_frame_t *p_frame) {
	if (sem_tx_complete == NULL) {
		return -1;
	// Write the frame to the controller
	// wait for the frame tx to complete
	int rc = xSemaphoreTake(sem_tx_complete, 250);
	return rc;
Just decreas "Upload Speed" to 460800 in case the sketch upload does show communication errors.


Select 1M FS size:

LittleFS is a file system which can be used in WIO for uploading user bitmaps and scripts.
Installing the Arduino IDE Plugin for uploading data:

WIO Sketch

Copyright © 2002-2022 Robert Jan Versluis,

WIO is firmware for controlling Throttle, I2C, LEDs, Servos, RFID, Displays and DCC.

The source code is public but not open source licensed, and it should be used only to compile and load it on the LOLIN D1 Mini or D32.


:!::!::!: The directory MUST be renamed after unpacking the ZIP from "wio-master" into "WIO". :!::!::!:

The sources are unusable in the Arduino IDE without renaming the main source directory, and will bring only a mess of compile errors!

(Important: The USB cable has to be a data cable, a charging-only cable doesn't work)


esp-downloadtool.jpgespressif_flash_tool_chip.jpgespressif_flash_tool.jpg Use the Espressif tool to upload the WIO Binary.

Compile output

The red FastLED pragma messages, which is information only, can be ignored, as long as the last two white lines show up:

 #    pragma message "FastLED version 3.003.002"
 #      pragma message "No hardware SPI pins defined.  All SPI access will default to bitbanged output"

Sketch uses 293716 bytes (28%) of program storage space. Maximum is 1044464 bytes.
Global variables use 33104 bytes (40%) of dynamic memory, leaving 48816 bytes for local variables. Maximum is 81920 bytes.
Pratfall: Many Micro USB cables do only provide 5V and no data, and cannot be used to program.

Setting up the WiFi can be done with the Arduino Serial Monitor 115200 bps, or by modifying the USERCNF.h:

#1CConnecting to [secure.home]
#13WiFi try to connect
#13WiFi try to connect
#17WiFi connected RSSI=-55

Output after a ? command:

revision=458 WIO (c)Rocrail RSSI=-52
EEPROM size=3804
Free heap=174271
I/O state=00 00 00 00
SPIFFS total=1345kb used=0kb
file: Disco01.led size=110
options=0xC2 0x01 0x00 0x00

User Configuration

The USERCNF.h file can be used for initial, first boot, WiFi and Rocrail server values.
The values must be set before compile and upload.
Afterwards those values can be changed with monitor commands.
:!: The values in the USERCNF.h-file are only used, if there is no configuration yet (new device).
- If the values in the flash memory of an existing WIO-device should be replaced by those in the USERCNF.h, the option "Erase Flash" in the Arduino-IDE has to be set to "All Flash Contents".
- If just the firmware of an existing WIO-device should be updated, without changing the configuration (e.g. WLAN-settings), set the Arduino-IDE to "Erase flash → only Sketch".

Monitor commands

The Arduino Serial Monitor can be use with 115200 bps to change WIO settings.

  1. If RailCom has been activated the baudrate switches automatically to 250000 and the Serial Monitor is read only.
  2. If ID12 has been activated the baudrate switches automatically to 9600 and the Serial Monitor is read only.

Basic connection setup can also be done on the Maintenance Tab of the WIO Setup Dialog.

Command Description Default Remark
? Shows the current settings and how to change them.
! Dumps the used EEPROM memory.
*sod Force Start of Day
*scan List all available WiFi APs
*ssid1=<value> Set the WiFi access point SSID. - Primary SSID (max. 30 characters)
*pwd1=<value> Set the WiFi password. A WiFi reconnect is triggered. - Primary WiFi password (max. 30 characters)
*ssid2=<value> Set the WiFi access point SSID. - Alternative SSID (max. 30 characters)
*pwd2=<value> Set the WiFi password. A WiFi reconnect is triggered. - Alternative WiFi password (max. 30 characters)
*server=<value> Set the Rocrail Sever IP or Name. - May be a CSV of max 30 characters.(1.71+)
Example: "mba2019,win2019"
If set to auto it will have the same effect as the autoserver parameter.
*autoserver=<value> Set the Rocrail Server auto search with R2RNet. see USERCNF.h → ENABLE_R2RNET 0=off, 1=on
*name=<value> Optional node name. -
*id=<value> Node number/throttle ID; Should be unique. 33
*io=<value> WIO type. i2cled
*i2c=<value> I2C port configuration. oooooooobbbbbbbboooooooobbbbbbbb
*steps=<value> Number of rotary steps. 127
*pulse=<value> Output pulse length in 100ms units. 5
*canprot=<value> CAN protocol MBUS 0=MBUS, 1=RCAN
*dccslave=<value> DCC role Master 0=Master, 1=Slave(Booster)
*trace=<value> Trace level 0 0=None, 2=Info, 4=Debug
Only for current session except for 2(Info).
*ptmain=<value> Service mode, PT, on the main H-Bridge 0 (volatile) 0=off, 1=on
Only for testing!
*pwm=<value> PWM size for mobile motor control - 600=10Hz
*display=<value> Display type: 0=96x16, 1=128x32, 2=128x64, 3=SH1106 - 1
*list List all files
*dump=</filename> Hex dump of file. Prefix filename with a '/'
*dumpa=</filename> ASCII dump of file. Prefix filename with a '/'
*pwmslave=<value> Provide sync on HALL pin. master 1=slave, 0=master
*pwm50=<value> 50Hz software PWM freq. 25Hz 1=50Hz, 0=25Hz
*pwmhardware=<value> 100Hz hardware PWM freq. software PWM 1=hardware, 0=software

Note: Replace <value> to meet the local WiFi environment and setup.
Note: A reset is necessary after changing the WIO Type.

Port type Description
i Input
o Output
b Block: Input with a 2 second off delay.
p Pulse: Output with auto off.

IO Type Configuration

IO Type I2C 32I/O FastLED Servo RFID Display DCC
throttle - - - - - -

OTA Updating

Must be activated by WIO Dialog.

If it's not possible, or cumbersome, to update by USB, the WIO can also be updated "Over The Air" (OTA).

Just select the desired WIO from the list instead of the USB port, and upload.
If asked for a Password, this is the same as for the Access Point (Default "12345678").

OTA Install from scratch

RIC - Throttle

Note: RIC is no longer supported in the firmware, and is replaced by WIO Control.

Note: RIC controls locos by address, not by ID. So the first one in the list will be used if multiple locos share the same address.
The pocket throttle I/O mode needs a rotary switch, one LED and four buttons.
The LED can also be the build in one. (D4)

Proto Type 1

Pin Usage Click Long click
D5/D6 Rotary - -
D7 Rotary switch Change direction Wait/Release loco
D4 Onboard LED - -
D1 F1 F1 F5
D2 F2 F2 F6
D3 F3 F3 F7
D0 F4 F4 F8
A0 Battery - -


F0 is flipped if both F3 and F4 are pressed.

Emergency Break

An emergency break will send to the server if both F1 and F2 are pressed.

Loco selection

Loco 1 is selected by default.
Select loco 1 if both F1 and F4 are pressed.
Select loco 2 if both F2 and F3 are pressed.

LED Meaning
On No WiFi connection.
Very fast flashing 10Hz No Rocrail server connection.
Off Idle mode.
Fast flashing 5Hz Waiting for a dispatch.
Slow flashing 1Hz Operating mode.


At boot the LED will turn on until a WiFi connection is established.

Catch a Locomotive

  1. In case the LOLii did not catch a dispatched loco, and the rotary is pressed long, about 2 seconds, the LED will start flashing fast.
  2. If the LOLii sees in this mode a loco dispatch, it will catch it and the LED will start flashing slow.
  3. This loco catch will be saved in the flash memory and reused at reboot if it was not released.

Speed Control

  • Turn the rotary for speed changes.
  • A short rotary press will flip the loco direction.

Function Control

The four function buttons represents F1 to F4.
With a long click F5 to F8 can be accessed.
A function will be flipped after releasing the button to be able to process long clicks. (Same as with smartphones.)

Release a Locomotive

  1. Press the rotary long, about 2 seconds,
  2. A release message is send.
  3. The LED will go off.

Battery Control

The analog input will check the battery voltage.
If the voltage is below a certain level, LOLii will send automatically a zero speed command to the locomotive and a release command.
The LED will start blinking very fast as long the battery is not drained completely.

Server discovery

If the Rocrail Server has R2RNet active on multicast address, the WIO can retrieve the server name/IP to connect it to the 8051 client port automatically.


  • Connects directly to the Rocrail Server Client port 8051.
  • WiFi and Server connection recovery.
  • 32 digital I/O, MCP23017, compatible with all GCA interfaces.
    • Input
    • Output
    • Block
    • Pulse
  • 100 LEDs compatible with WS2812 on D8. (Color type output in Rocrail.)
    • RGB color
    • Brightness
    • Dimming
    • Flashing
  • 4 Servos
    • Adjustable movement speed
    • Positions are saved in the plan.xml, Output/Switch, which makes swapping of hardware easier.
    • Reached end positions are saved in flash to provide a stable reboot.
  • DCC Command Station
  • Up to 255 units in the same WiFi network. (Depending on the IP configuration and availability.)
  • An alarm will be generated if 'a live' messages are no longer come in.
  • Output/Switch commands are acknowledged after they have been processed. (Blink outputs are not acknowledged.)
  • Input events must be acknowledged within 100ms. After this timeout a resend will occur. (Max. 5 retries.)

I/O Extender PCF8574P

Up to 4 pieces of I/O extender type PCF8574 can be used as alternative to the 2 pieces of MCP23017.

  1. 0x20 and 0x21 should not be available as I2C slave ID's. (No MCP23017's installed.)
  2. The slave ID's of the PCF8574 must start with 0x22.

Note: Check for the correct type to match the 0x20 base address: PCF8574P or PCF857T. (The PCF8574A type starts with base address 0x38.)


Rocrail WIO
Interface ID "WIO"
Node ID (Bus) ID
Address I2C Port
Address LED Port
Address Servo Port

This addressing schema is used for:

  • Outputs
  • Switches
  • Signals
  • Sensors

Dual Coil Switches

Disable the 'Accessory' and 'Single gate' options, and select output type.

The next address for none single gate switches is used for the turnout command.
So if on port 1 is a dual coil switch, port 2 should not be used, and the second switch goes on port 3.
Both I2C outputs are automatically used as type 'p' Pulse.
Possible hardware:

The output blink and delay options can be used to blink an I2C port.
If the delay is zero the default pulse length will be used.


ws2812.jpgws2811-chip.jpg The addressing is the same as normal outputs.

Dimming information:
WIO version 875+
The dimming frequentation depends of Controller Steps and Output/Signal delay.
The brightness is divided by the number of steps, and multiplied by the delay value which is subtracted/added every refresh cycle to the new brightness.
A low step and high delay value will cause fastest dimming.


  1. WIO-ID: Bus
  2. LED number: Address
  3. LED range: ON parameter
  4. The Interface → Color option and type light must be set
  5. Brightness is set by Interface → Value
  6. Dimming step is set by Interface → Delay (0…15) (A value of zero deactivate dimming.)
  7. The Interface → Blink option may be used to flash the LED
  8. The LED color is set by Color → RGB


  1. WIO-ID: Bus
  2. LED offset: Address
  3. Port type: LED
  4. Control type: Aspect number (Max. 6 sub LEDs → 2 x WS2812)
  5. Brightness

The aspect values are compatible with RocNetNode Pi08. (WIO version 0.81+)


  1. WIO-ID: Bus
  2. LED offset: Address
  3. Port type: Output
  4. Control type: Aspect number

The aspect values are compatible with RocNetNode Pi08. (WIO version 0.81+)

Charlieplexing Signal Support

Only available on WIOesp32 16 I/O, WIOpico 16 I/O, SIOpico
A Rocrail signal with control aspects and port type multiplex, uses 4 pins starting with the port offset.
The refresh rate is about 250µs.
Aspect values are used from the details tab. 24bits are used, the upper 12bits are for blinking.
Example: LED 1 and 2 on and LED 2 blinking: 0x002003 → Aspect value = 8195

A second signal on the mast can be defined in Rocrail with address + 100 to combine it with the main signal.

Brightness sets brightness, only values ​​between 200-255 can be used. A value < 200 is set to 200.
Fading with dimming is not possible.

LED Nummber for Viessmann Multiplex Signal
112HL Vr_Ge_ODistant signal yellow above
213H L Hp_Rt_RMain signal red right
314H LHp_Rt_LMain signal red left
421LH Vr_Gr_ODistant signal green above
523 HL Vr_Gr_uDistant signal green below
624 H L
731L H Hp_GeMain signal yellow
832 LH Vr_Ge_UDistant signal yellow below
934 HL Hp_Ws_LMain signal white left
1041L HHp_GrMain signal green
1142 L H
1243 LHHp_Ws_RMain signal white right

For a correct display of the main signal at red and shunting, the distant signal must be blanked.
The brightness value in the main and distant signal must be identical.

Multiplex inputs from Vissmann, viewed from below on the connector.


The addressing is the same as normal outputs.

Control Output Switch Signals Segment Turntable Range
WIO ID Node ID (Bus) Node ID (Bus) Node ID (Bus) Node ID (Bus) 1…255
Servo port Address Address Address Address 1…4
Extra options - Single gate ON - - -
Accessory - - Details -
Position 1 Parameter ON Parameter RED Value 0 * - 0…180°
Position 2 Parameter OFF Value GREEN Value 1 * - 0…180°
Position - - - Decoder Trak number PWM 500…2500 ²
Moving speed Delay Switch time Dim Step delay 1…10
Target Port type "Servo" Port type "Servo" Port type "Servo" Type wioservo -

* Details tab, enter using the field with decimals in the Value button
² Attention, too high or too low values ​​can damage the servo start with PWM 1500 = 0°.
The value of the servo angle must be confirmed with enter in the decimal field.


Make sure that there are no servos and LEDs connected when switching to RFID.

Not possible with WIO Type I/O16, please use ID-12LA here.


  1. Two RFID RC522 readers are supported.
  2. It needs 5 extra ports; Parallel Servos are not possible.
  3. Reporting addresses are 100 and 101. (In Rocrail 101 and 102.)
  4. Automatic sensor off event after 1500ms. (Before it must be acknowledged by the server.)
  5. Four times retry until acknowledge, then give up.

Signal D1 Mini ESP 8266 RFID RC522
Slave Select 1 D3 1 (SDA) reader 1
Slave Select 2 D0 1 (SDA) reader 2
SCK D5 2 (SCK)


rfid-card-antenna.jpg id12la-pin6-led-taginrange.jpg
Optional a RFID reader from type ID-12LA can be connected to the RX pin for detecting tags which will be reported to Rocrail.
The tag is used as Sensor ID or UID-Name, decimal dot formatted.
The GCA RFID board can be used to mount and connect the ID-12LA.
The serial monitor will be set to 9600bps.
Note 1: This is to scan tags between the rails to let Rocrail know where the running vehicle is.
Note 2: Use selected Tags which respond rapidly.

Pins I2C

Pin Usage
A0 Power monitoring
D4 Build in LED
D8 LEDs (FastLED)

Pins S88

ESP8266 ESP32 PicoW Usage
D0 12 10 PS
D5 17 11 Reset
D6 26 12 Clock
D7 27 13 Data

Display SSD1306/SH1106

Example. {f8} on a SH1106 display.

Two displays can be connected to the I2C of Type SSD1306 with the I2C addresses 0x3C and 0x3D.
Formatted text is compatible with RocDisplay.
WIO supports only a subset, and some new lower case commands are introduced.
Code page is ISO 8859 Latin for font {F0}; {F1} is 7 bit ASCII only.


The Bus is used for the WIO ID, and the Display number for selecting between 1 and 2. (0x3C or 0x3D)
The Address value is not used.


Up to 16 display can be used with Display multiplexing.

Supported Formatting

Formatting commands are enclose in curly brackets. Example:

{g1}{E}{L0}{X0}Hello World!{P}
Command Parameter Description Remark
{A…} 0…9 & : Enlarged numbers. Example: {A%hour%:%min%}
{B#} #=0-99999999 Read an AMP file, "#.amp", from SPIFFS, and draw the bitmap on the current position.
{B'name'} or {B[name]} AMP file name Read an AMP file, "name.amp", from SPIFFS, and draw the bitmap on the current position. The name must be between square brackets3) or single quotes.
{E} - Erase display buffer. An extra {P} is needed to erase the display.
{F#} #=0-2 Select font. 0=7x5 1=6x5w 2=6x5n Font 5x5 is not supported because its unreadable.
{H#} #=0-255 Set the display contrast.
{I#} #=0-1 Invert the display. 0=normal 1=inverted
{L#} #=0-3 Goto line. The range depends on the display size. (Y = L * 8)
{P} - Copy buffer to the display.
{R#} #=0,2 Set display mapping rotation. 0=0° 2=180° See also Setup Display
{?V} - Show firmware version.
{X#} #=0-127 Goto column. The range depends on the display size.
{Y#} #=0-32 Goto row. The range depends on the display size.
{c#} #=1-16 Draw an analog clock with the given radius on the current position. Only one (fast) clock per display will be updated.
{g#} #=0,1,2,3 Set display geometry. 0=96x16, 1=128x32, 2=128x64, 3=SH1106 (1 is default) This is for testing only. To save CPU load set the display option.
See also Setup Display
{i} - Toggle inverted text.
{s#} #=1-x Draw scrolling text on the current position, with a view width of n characters. Example: {s12}Scrolling text to show…{s}
{d} - Scroll one text line down.
{f#} #=1-2 7-Segment fast clock. Only one (fast) clock per display will be updated.
{f7} - User defined fast clock.
Needed files: 0.amp…9.amp and colon.amp
Example data:
Max. file size is 1024 bytes per amp.
{X#} and {L#} are used for position.
The DISPLAY_FASTCLOCK must be set to true in the USERCNF.h
{f8} - Same as {f7} but with leading hour zero if needed. Example: 08:22 instead of 8:22
{p} - Swap displays.
{l#,#} - Draw a line from X,Y to #,#
{r#,#} - Draw a rectangle left upper X,Y to right under #,#
{z#} - Draw a circle with center and radius #
{x#,#} - Draw a pixel at #,#
{+} - Use large characters from file system. The characters are on the file system in the amp format. Example: 3.amp
{-} - Stop using large characters.

Note: If the geometry is not default, 128x32, the text MUST start with a {gn} command for selecting the right geometry.

7-Segment Display HT16K33

adafruit-ht16k33.jpg Fast Clock
The Adafruit breakout board HT16K33 is supported on I2C address 0x70.
It displays alternate time, date and temperature.
With the NTP_CLOCK USERCNF.h setting the "" service will be used to get the time of day instead from the Rocrail server. It will not alternate between date and temperature.

DCC Generator


WIO supports following DCC packets

  • Loco speed and direction. (No support for 14 speed steps.)
  • Loco functions 0-32.
  • PoM set/get. (A RailCom detector, GCA214, is needed for PoM get.)
  • Accessories.
  • BinState
  • Programming Track; Service mode. (A second H-Bridge is required: WIO-Prog2)
    1. Global power must be ON
    2. PT must be set to ON
    3. Read/Write CV
  • Loco addresses >= 100 are regarded as long address.
  • Short address 111 is used as dummy to trigger other decoders to broadcast there address.


  • 100% NMRA timing conform.
  • Automatically Power OFF after a Rocrail Server connection loss.
  • Shows activity on a display if one connected.
  • 48 slot refresh stack with auto purging.
  • 12 accessory command queue.

Pins DCC

Pin Usage Remark
D6 & D7 DCC symmetric signal.
D5 Enable H-Bridge 1 Operation
D8 Enable H-Bridge 2 Service


To use the 3.3V level a 470 Ohm resistor must be added parallel to R1.

Mobile Addressing

IID WIO Remark
Node ID (Bus) WIO ID
Address DCC decoder address. Addresses > 99 are regarded as long DCC address.
Speed steps 28 or 128


Use the WIO as mobile decoder.
The locomotive Bus value must be set to the WIO ID.
The number of Decoder Steps must be set in the range 50 to 100.


Pin Usage H-Bridge Remark
D0 Lights front Cab1
D3 Lights rear Cab2
D5 Motor Enable ENA RC ESC servo PWM
D6 PWM forwards direction IN1
D7 PWM reverse direction IN2
D8 Servo PWM for coupler F1
I2C 1-32 Functions 1 to 32 The Function address must be set > 0.
A0 Battery monitor LiPo 3S + 100kΩ A0 32kΩ -

Acceleration/deceleration can be simulated with the locomotive interface parameter Mass. (10ms resolution.)
A mass value of 5 will increase/decrease the PWM 1 step at every 5*10ms.
Vstart and Vhigh, CV2/CV5, can be simulated with the Step range

Electronic Speed Controller

An Electronic Speed Controller, ESC, on pin D5 can also be used for motor control if this option is set.
Note: Only connect ground and PWM in case the ESC supports BEC.


railcom_cutout.jpg The serial connector on the WIO PCB can be used to connect it to an amplifier for reading RailCom data.
The GCA214 can be used as amplifier.
The following RailCom IDs are supported:

ID Channel Description
0 2 POM read
1 1 Low decoder address
2 1 High decoder address

The only way to activate RailCom reading in WIO is to set this option in the WIO Dialog. (WIO 0.105, Rocrail 2.1.212)
The serial bps will switch to 250000, and the monitor will be read only. So with this option active its not possible to setup the WIO by monitor commands.


bmp280.jpgtsl2591.jpg One BME280/BMP280 sensor, connected to I2C, is supported for temperature, pressure and humidity.
The USER_ALTITUDE in the USERCNF.h must be adjusted to meet the local altitude for correct pressure values.
One TSL2591 'Light-to-Digital Converter' sensor, connected to I2C, is supported for calculating brightness.

Dynamic Text

Temperature, pressure and humidity can be used as text and XMLScript variables.
See: Dynamic Text


Sound can be played on ESP32 boards using one of the DAC pins. (GPIO25 or GPIO26)
The USER_SOUND in the USERCNF.h must be set to true:

// Sound
#define USER_SOUND          true

Supported RIFF Wave format:

  • PCM type
  • Sample rate 11.025 Hz
  • 16 sample bits
  • One channel (Mono)


  • Type: Sound
  • Command: Play
  • Parameter: Sound file incl. path like: "/F9.wav"
  • Interface Bus: WIO ID


<ac id="F9" cmd="play" param="/F9.wav" type="sound" iid="WIO" bus="38" addr="0" port="0"/>


The DAC is only capable to use 8 bits. The 16 bit data must be interpreted, which is not possible without data loss.
To get the best result:

  • Normalise the sounds files so the data uses the full 16 bit.


The WIO-02 supports two types of step motors: 4-wire and 3-wire step driver.

WIO-02 4-wire 3-wire Remark
32 IN1 CLK+
13 IN2 DIR+
15 IN4 -
25 - Hall/Reed calibrate sensor
- VCC 12V-45V DC External power supply

Turntable Setup

Turntable Interface
Field Value Remark
Node ID WIO-02 ID
Address 1 Fixed
Lights 1…32 Optional bridge cabin lights.
Digital output port on the same WIO-02.
Decoder steps 0-16777215 Nr of steps for one 360° rotation.
In case of a 28BYJ-48: 4096 steps.
Correction 0-255 To compensate for the gear backlash.
Step delay 1-10 Size of the start and deceleration ramp
Offset -32767…+32767 Calibration correction point in steps.
Type wio
rotation speed 0-100%

The number of decoder steps for one turntable rotation is needed to calculate the shortest way.

Turntable Tracks (Example 4096 steps)
Track Decoder track
0 0
12 1024
24 2048
36 3072

XML example: (Only mandatory attributes are listed.)

  <tt ori="west" id="tt1" x="11" y="4" z="0" pos="0" iid="RCAN-1" bus="102" addr="1" type="wio" decsteps="4096">
    <track nr="0" decnr="0"/>
    <track nr="12" decnr="1024"/>
    <track nr="24" decnr="2048"/>
    <track nr="36" decnr="3072"/>


Field Value Remark
Adress 1 fix
Parameter on 0-16777215 Number of steps counterclockwise
Parameter off 0-16777215 Number of steps clockwise
Delay 0-255 rotation speed
If the value is >0, an acceleration and braking ramp is generated.
Type Motor

Calibration is not possible!


gc2a-wio-can.jpg The WIO CAN type can be used as CAN-WiFi bridge for


Pin mapping for using the SPI MCP2515(16MHz) on the GC2a:

Name Nano Lolin D1 Mini Lolin D32 Remark
5V 5V 5V 5V(USB)
CS D10 D3 GPIO14 Chip Select
MOSI D11 D7 GPIO23(MOSI) Master Output, Slave Input
MISO D12 D6 GPIO19(MISO) Master Input, Slave Output
SCK D13 D5 GPIO18(SCK) Serial Clock

The Lolin D1 must be connected to 5V USB without power supply from the CAN bus.
A WIO-CAN kit will become available.


The current WIO firmware, 1.94, does use the internal CAN controller, and uses therefor only the MCP2551/2561. (SPI CAN is no longer supported for the MCP2515)
In case of ESP32 the CAN communication is always activated, independent of wich WIO type is selected.

Connection ESP32 Pin MCP2561
TXCAN 16 1

Mobile RFID reader

The WIO can also be used as mobile RFID reader and I/O.
The WIO ID must be set in the loco Secondary Address field.

Sensor setup

Loco [ICE] reports RFID event 56:101 [] ON

The reported RFID must mach with a Sensor-ID in Rocrail.
The sensor in Rocrail should have an address unique other than zero.
The ID must be set in this notation: RFID Notation
The Rocrail traces can be used to copy this ID or the Sensor Monitor.

Function setup

To dispatch functions to a WIO the function must be setup with Function address and FX.


wio-keypad.jpg A KeyPad is supported on WIO Type IO16 on I/O connector 1. The # key will send the input to Rocrail es Text event. Rocrail will look up a Text object with this NodeID set on the interface tab.
With the * key the input can be corrected.
If a display is connected the input will be shown on line 3, but can be changed in the USERCNF.h. (Zero based line offset.)
Supportes KeyPads: 3x4 and 4x4. The 4x4 has "ABCD" on the extra key column.
It is recommended to set the ports 1…8 on the setup tab as follows:


The firmware for IO-Type RIC does not function without pull-up resistors on the button inputs, including the rotary switch.

Schedules & PCBs

The published hardware are prototypes, are incomplete and not ready for release.
Only original GCA Kits are supported.

Trouble Shooting

LOLIN vs Wemos

Top Bottom
LOLIN D1 mini Wemos mini LOLIN D1 mini Wemos mini
d1-top.jpg d1-bottom.jpg
Pin Lolin Wemos
D3 - Won't boot in case low.

Very slow

If an I2C module, like the Pi02 or Pi03, is connected to the I2C bus of the WIO, and has no power, it will slowdown the processing and no other I2C devices are detected. (Multiple seconds between the loop calls.)
The P82B715 I2C-bus extender seems to drain the I2C clock and data lines, which will confuse the ISR in the Wire library.
The Pi08, with the PCA9622 chip, does not suffer this problem with its internal I2C-bus extender.


Make sure all conneted I2C modules are powered up at the same time as the WIO.

macOS "Big Sur"

Upload tool ESP8266

Upload tool ESP32

Programming WIO Binary with Arduino IDE Tools

Arduino IDE 1.8.16

macOS "Big Sur"


export WIOBIN=~/Downloads/WIO.ino.d1_mini.bin

/Users/$USER/Library/Arduino15/packages/esp8266/tools/python3/3.7.2-post1/python3 \
/Users/$USER/Library/Arduino15/packages/esp8266/hardware/esp8266/3.0.1/tools/ \
--chip esp8266 --port /dev/cu.usbserial-110 --baud 921600 --before default_reset --after hard_reset write_flash 0x0 $WIOBIN


~/Library/Arduino15/packages/esp32/tools/esptool_py/3.1.0/esptool \
--chip esp32 \
--port /dev/cu.usbserial-01B9FA0C \
--baud 921600 \
--before default_reset \
--after hard_reset write_flash \
-z \
--flash_mode dio \
--flash_freq 80m \
--flash_size 4MB \
0x10000 WIO.ino.d1_mini32.bin

Windows 10

set WIOBIN=\Users\%USERNAME%\Downloads\WIO.ino.d1_mini.bin

C:\Users\%USERNAME%\AppData\Local\Arduino15\packages\esp8266\tools\python3\3.7.2-post1/python3 -I C:\Users\%USERNAME%\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\3.0.2/tools/ --chip esp8266 --port COM3 --baud 921600 --before default_reset --after hard_reset write_flash 0x0 %WIOBIN%

PiOS-64 "Buster"

export WIOBIN=/home/$USER/Downloads/WIO.ino.d1_mini.bin

/home/$USER/.arduino15/packages/esp8266/tools/python3/3.7.2-post1/python3 -I /home/$USER/.arduino15/packages/esp8266/hardware/esp8266/3.0.2/tools/ --chip esp8266 --port /dev/ttyUSB0 --baud 921600 --before default_reset --after hard_reset write_flash 0x0 $WIOBIN 
arduino/wio-en.txt · Last modified: 2024/07/01 12:12 by rjversluis