EX-FastClock

Supported Devices

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This page outlines the microcontrollers that are supported for use with EX‑IOExpander, including outlining the pins available for use.

When uploading the EX‑IOExpander software, the device type is detected by the compiler in either the Arduino IDE or PlatformIO, so no configuration is necessary on the EX‑IOExpander device itself (aside from the I2C address of course).

All allocation of pins is done via the device driver (see EX-CommandStation device driver).

All Vpins outlined on this page assume use of the default starting Vpin of 800, so you will need to review the Vpin map displayed in the EX‑IOExpander serial console if using a different starting Vpin.

Arduino Nano

EX-IOExpander on Arduino Nano
Table 23 Arduino Nano pin allocations

Total pins

18

Digital capable pins

16

Analogue capable pins

6

PWM capable pins

6
Table 24 Arduino Nano and Pro Mini EX-IOExpander pin map at Vpin 800

Vpin

Pin

Digital

Analogue

PWM

800

2

Y

N

N

801

3

Y

N

Y

802

4

Y

N

N

803

5

Y

N

Y

804

6

Y

N

Y

805

7

Y

N

N

806

8

Y

N

N

807

9

Y

N

Y

808

10

Y

N

Y

809

11

Y

N

Y

810

12

Y

N

N

811

13

Y

N

N

812

A0

Y

Y

N

813

A1

Y

Y

N

814

A2

Y

Y

N

815

A3

Y

Y

N

816

A6

N

Y

N

817

A7

N

Y

N

Arduino Pro Mini

The Arduino Pro Mini comes in two variations; a 3.3V running at 8MHz, and a 5V running at 16MHz.

Warning

The 8MHz 3.3V Pro Mini is not 5V tolerant

The Pro Mini uses an identical pin map to the Arduino Nano.


Arduino Uno

EX-IOExpander on Arduino Uno
Table 25 Arduino Uno pin allocations

Total pins

16

Digital capable pins

16

Analogue capable pins

4

PWM capable pins

6
Table 26 Arduino Uno EX-IOExpander pin map at Vpin 800

Vpin

Pin

Digital

Analogue

PWM

800

2

Y

N

N

801

3

Y

N

Y

802

4

Y

N

N

803

5

Y

N

Y

804

6

Y

N

Y

805

7

Y

N

N

806

8

Y

N

N

807

9

Y

N

Y

808

10

Y

N

Y

809

11

Y

N

Y

810

12

Y

N

N

811

13

Y

N

N

812

A0

Y

Y

N

813

A1

Y

Y

N

814

A2

Y

Y

N

815

A3

Y

Y

N

Arduino Mega2560

EX-IOExpander on Arduino Mega2560
Table 27 Arduino Mega pin allocations

Total pins

62

Digital pins

62

Analogue pins

16

PWM pins

12
Table 28 Arduino Mega EX-IOExpander pin map at Vpin 800

Vpin

Pin

Digital

Analogue

PWM

Vpin

Pin

Digital

Analogue

PWM

800

2

Y

N

Y

831

35

Y

N

N

801

3

Y

N

Y

832

36

Y

N

N

802

4

Y

N

Y

833

37

Y

N

N

803

5

Y

N

Y

834

38

Y

N

N

804

6

Y

N

Y

835

39

Y

N

N

805

7

Y

N

Y

836

40

Y

N

N

806

8

Y

N

Y

837

41

Y

N

N

807

9

Y

N

Y

838

42

Y

N

N

808

10

Y

N

Y

839

43

Y

N

N

809

11

Y

N

Y

840

44

Y

N

N

810

12

Y

N

Y

841

45

Y

N

N

811

13

Y

N

Y

842

46

Y

N

N

812

14

Y

N

N

843

47

Y

N

N

813

15

Y

N

N

844

48

Y

N

N

814

16

Y

N

N

845

49

Y

N

N

815

17

Y

N

N

846

A0

Y

Y

N

816

18

Y

N

N

847

A1

Y

Y

N

817

19

Y

N

N

848

A2

Y

Y

N

818

22

Y

N

N

849

A3

Y

Y

N

819

23

Y

N

N

850

A4

Y

Y

N

820

24

Y

N

N

851

A5

Y

Y

N

821

25

Y

N

N

852

A6

Y

Y

N

822

26

Y

N

N

853

A7

Y

Y

N

823

27

Y

N

N

854

A8

Y

Y

N

824

28

Y

N

N

855

A9

Y

Y

N

825

29

Y

N

N

856

A10

Y

Y

N

826

30

Y

N

N

857

A11

Y

Y

N

827

31

Y

N

N

858

A12

Y

Y

N

828

32

Y

N

N

859

A13

Y

Y

N

829

33

Y

N

N

860

A14

Y

Y

N

830

34

Y

N

N

861

A15

Y

Y

N

STMicroelectronics NUCLEO-F411RE

Warning

Support for the F411RE is experimental at best right now. While the software compiles and it appears to operate normally, only basic I/O testing has been performed.

Note also that as a 3.3V microcontroller, not all pins are 5V tolerant.

Nucleo F411RE pin out

The Nucleo F411RE is a 3v3 microcontroller with more available I/O pins than an Arduino Uno in a similar, but slightly larger form factor. The pin numbers used are defined using the Morpho pin names associated with connectors CN7 and CN10.

Vpins are allocated in ascending order from the STLink/USB connector end of each Morpho connector, with the odd numbered pin row first, then the even number row, hence the pin names aren’t sequential.

Numerous I/O pins are connected to other devices or perform multiple functions which result in pin conflicts, so the only pins included are those that are able to successfully be set to input mode on startup.

Note

PC13 has a switch (blue button) with pullup resistor attached, so this is suitable as an input only (without pullups enabled) unless you disconnect SB17.

In addition, PA5 is the green LED.

Table 29 NUCLEO-F411RE pin allocations

Total pins

40

Digital pins

40

Analogue pins

14

PWM pins

25
Table 30 F411RE EX-IOExpander pin map at Vpin 800

Vpin

Pin

Digital

Analogue

PWM

Vpin

Pin

Digital

Analogue

PWM

800

PC10

Y

N

N

820

PC7

Y

N

N

801

PC12

Y

N

N

821

PA9

Y

Y

Y

802

PA15

Y

N

N

822

PA8

Y

N

Y

803

PB7

Y

N

N

823

PB10

Y

N

Y

804

PC15

Y

N

Y

824

PB4

Y

N

N

805

PC2

Y

N

Y

825

PB5

Y

N

Y

806

PC3

Y

N

N

826

PB3

Y

N

Y

807

PC11

Y

Y

Y

827

PA10

Y

N

Y

808

PD2

Y

Y

Y

828

PC8

Y

N

N

809

PA0

Y

Y

N

829

PC6

Y

N

Y

810

PA1

Y

Y

Y

830

PC5

Y

Y

Y

811

PA4

Y

Y

N

831

PA12

Y

N

Y

812

PB0

Y

Y

N

832

PA11

Y

N

Y

813

PC1

Y

Y

N

833

PB12

Y

N

Y

814

PC0

Y

Y

N

834

PB2

Y

N

Y

815

PC9

Y

N

Y

835

PB1

Y

N

Y

816

PA5

Y

N

Y

836

PB15

Y

N

Y

817

PA6

Y

N

Y

837

PB14

Y

N

Y

818

PA7

Y

Y

N

838

PB13

Y

N

Y

819

PB6

Y

Y

Y

839

PC4

Y

Y

N

STMicroelectronics NUCLEO-F412ZG

Warning

Support for the F412ZG is experimental at best right now. While the software compiles and it appears to operate normally, only basic I/O testing has been performed.

Note also that as a 3.3V microcontroller, not all pins are 5V tolerant.

The Nucleo F412ZG is a 3v3 microcontroller with significantly more available I/O pins than an Arduino Mega. The pin numbers used are defined using the Morpho pin names associated with connectors CN11 and CN12.

Vpins are allocated in ascending order from the STLink/USB connector end of each Morpho connector, with the odd numbered pin row first, then the even number row, hence the pin names aren’t sequential.

Numerous I/O pins are connected to other devices or perform multiple functions which result in pin conflicts, so the only pins included are those that are able to successfully be set to input mode on startup.

Note

PC13 has a switch (blue button) with pullup resistor attached, so this is suitable as an input only (without pullups enabled) unless you disconnect SB17.

In addition, PB0 is the green LED, PB7 is the blue LED, and PB14 in the red LED.

Table 31 NUCLEO-F412ZG pin allocations

Total pins 97

97

Digital pins

97

Analogue pins

16

PWM pins

40
Table 32 F412ZG EX-IOExpander pin map at Vpin 800

Vpin

Pin

Digital

Analogue

PWM

Vpin

Pin

Digital

Analogue

PWM

800

PC10

Y

N

N

849

PB6

Y

Y

Y

801

PC12

Y

N

N

850

PC7

Y

Y

Y

802

PF6

Y

N

N

851

PB10

Y

Y

Y

803

PF7

Y

N

N

852

PB4

Y

N

N

804

PA15

Y

N

Y

853

PB5

Y

N

Y

805

PB7

Y

N

Y

854

PB3

Y

N

Y

806

PC13

Y

N

Y

855

PA2

Y

N

Y

807

PC2

Y

N

Y

856

PA3

Y

N

N

808

PC3

Y

N

N

857

PD13

Y

Y

Y

809

PD4

Y

Y

Y

858

PD12

Y

N

Y

810

PD5

Y

Y

Y

859

PD11

Y

N

Y

811

PD6

Y

Y

N

860

PE10

Y

N

Y

812

PD7

Y

Y

Y

861

PE12

Y

N

Y

813

PE3

Y

Y

N

862

PE14

Y

N

Y

814

PF1

Y

Y

N

863

PE15

Y

N

Y

815

PF0

Y

Y

N

864

PE13

Y

N

Y

816

PD1

Y

Y

N

865

PF13

Y

Y

N

817

PD0

Y

N

N

866

PF12

Y

Y

Y

818

PG0

Y

N

N

867

PG14

Y

N

N

819

PE1

Y

N

N

868

PD10

Y

Y

Y

820

PG9

Y

N

N

869

PG4

Y

N

N

821

PG12

Y

N

N

870

PC8

Y

N

Y

822

PC11

Y

N

N

871

PC6

Y

N

Y

823

PD2

Y

N

N

872

PC5

Y

N

N

824

PA0

Y

N

N

873

PB12

Y

N

Y

825

PA1

Y

N

N

874

PB11

Y

N

N

826

PA4

Y

N

N

875

PB2

Y

N

N

827

PB0

Y

N

Y

876

PB1

Y

N

Y

828

PC1

Y

N

N

877

PB15

Y

N

Y

829

PC0

Y

N

N

878

PB14

Y

N

Y

830

PD3

Y

N

N

879

PB13

Y

N

Y

831

PG2

Y

N

Y

880

PC4

Y

N

N

832

PG3

Y

N

N

881

PF5

Y

N

Y

833

PE2

Y

N

Y

882

PF4

Y

N

Y

834

PE4

Y

N

N

883

PE8

Y

N

N

835

PE5

Y

N

N

884

PF10

Y

N

Y

836

PF2

Y

N

N

885

PE7

Y

N

Y

837

PF8

Y

N

N

886

PD14

Y

N

N

838

PF9

Y

N

Y

887

PD15

Y

N

N

839

PG1

Y

N

N

888

PF14

Y

N

N

840

PE6

Y

N

N

889

PE9

Y

N

N

841

PG15

Y

N

N

890

PE11

Y

N

N

842

PG10

Y

N

N

891

PF3

Y

N

N

843

PG13

Y

N

N

892

PF15

Y

N

N

844

PG11

Y

N

N

893

PF11

Y

N

N

845

PC9

Y

N

Y

894

PE0

Y

N

N

846

PA5

Y

N

Y

895

PG8

Y

N

N

847

PA6

Y

N

Y

896

PG5

Y

N

N

848

PA7

Y

Y

N

Arduino Zero (or SAMD based clone)

Warning

The Arduino Zero (and SAMD based clones) are 3v3 only and are not 5V tolerant.

Support for the Arduino Zero (or other SAMD clones) is experimental at best right now. While the software compiles and it appears to operate normally, no actual I/O testing has been performed.

Table 33 Arduino Zero pin allocations

Total pins 27

Minimum

Maximum

Digital pins

21

27

Analogue pins

0

6
Table 34 Arduino Zero EX-IOExpander pin map at Vpin 800

Vpins

800

801

802

803

804

805

806

807

Digital Pins

0

1

2

3

4

5

6

7

Vpins

808

809

810

811

812

813

814

815

Digital Pins

8

9

10

11

12

13

22

23

Vpins

812

813

814

815

816

Digital Pins

24

38

39

40

41

Vpins

817

818

819

820

821

822

Analogue Pins

A0

A1

A2

A3

A5

A6

STMicroelectronics STM32F103C8T6 (Bluepill)

Warning

Support for the STM32F103C8T6 Bluepill is experimental at best right now. While the software compiles and it appears to operate normally, only basic I/O testing has been performed.

Note also that as a 3.3V microcontroller, not all pins are 5V tolerant.

EX-IOExpander on STM32F103C8T6 Bluepill

Image courtesy of arm MBED

Table 35 STM32F103C8T6 Bluepill pin allocations

Total pins

28

Digital capable pins

28

Analogue capable pins

10

PWM capable pins

19
Table 36 STM32F103C8T6 Bluepill EX-IOExpander pin map at Vpin 800

Vpin

Pin

Digital

Analogue

PWM

Vpin

Pin

Digital

Analogue

PWM

800

PC13

Y

N

N

814

PB11

Y

N

Y

801

PC14

Y

N

N

815

PB9

Y

N

N

802

PA15

Y

N

N

816

PB8

Y

N

N

803

PA0

Y

Y

N

817

PB5

Y

N

Y

804

PA1

Y

Y

Y

818

PB4

Y

N

Y

805

PA2

Y

Y

Y

819

PB3

Y

N

Y

806

PA3

Y

Y

Y

820

PA15

Y

N

Y

807

PA4

Y

Y

N

821

PA10

Y

N

Y

808

PA5

Y

Y

N

822

PA9

Y

N

Y

809

PA6

Y

Y

Y

823

PA8

Y

N

Y

810

PA7

Y

Y

Y

824

PB15

Y

N

Y

811

PB0

Y

Y

Y

825

PB14

Y

N

Y

812

PB1

Y

Y

Y

826

PB13

Y

N

Y

813

PB10

Y

N

Y

827

PB12

Y

N

N

Adding new devices

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Warning

When considering adding new devices to EX‑IOExpander, be sure to take into account whether they are 5V or 3.3V devices, and whether their I/O and I2C pins are 5V tolerant if they are 3.3V devices. New generation microcontrollers tend to be 3.3V, and some have 5V tolerant I/O pins (eg. STM32 Nucleo), but some are not 5V tolerant (eg. SAMD).

To connect 3.3V devices to a 5V EX‑CommandStation, they need to either be 5V tolerant, or you will need to use a level shifter to avoid letting the magic smoke out.

Adding new devices to the EX‑IOExpander software only requires additional information in the EX‑IOExpander software itself, with no changes required to the device driver loaded in your EX‑CommandStation.

In order to successfully add an additional device, you need to know the C++ preprocessor macro definitions for the architecture or platform, and for the specific variant or board itself. In addition, you need to define the pins available for use on the EX‑IOExpander device, and define the capabilities available for each pin.

For example, the AVR series (Uno, Mega, Nano) have the architure or platform macro defined as “ARDUINO_ARCH_AVR”, with the Nano having the variant or board specific macro “ARDUINO_AVR_NANO”, and there is a pin map defined that maps to this macro definition.

Files to be created/modified

When adding new devices to EX‑IOExpander, there are potentially three files to be added or modified:

  • device_functions.cpp - Contains the architecture/platform specific function to reboot via software

  • defines.h - Contains some device specific macro definitions

  • <device_type>.h - Contains the device specific macro definitions and the pin map

  • EX-IOExpander.ino - Loads the device specific files

Enabling software reboots

The architecture or platform macro is used to determine the correct method to reboot the device via the <Z> command, which is defined in the file “device_functions.cpp”.

If a new architecture or platform is being added, then this file will need to be updated with the suitable software command in the “reset()” function, otherwise a reboot via <Z> will not be available.

If the architecture or platform already exists, or there is no desire to reboot via software, then the only change required is to add the variant or board specific information.

Enabling serial input/output in defines.h

Some microcontrollers have different serial implementations, and therefore it may be necessary to specify the type of USB or serial port in use.

Currently, unless the device’s architecture is defined as “ARDUINO_ARCH_SAMD”, it will utilise the default Arduino “Serial” implementation. SAMD uses the “SerialUSB” implementation.

If additional serial support is required, this will need to be defined in “defines.h” as “USB_SERIAL”.

Defining the device macros in defines.h

There are three parameters to be defined in this file for each device type:

  • TOTAL_PINS - The total number of pins available on the device

  • NUM_PWM_PINS - The number of pins with PWM capability

  • HAS_EEPROM - Define only if the device has EEPROM capability

These need to be defined according to the CPU type macro definition. For example an Arduino Uno is defined as:

//  Arduino Uno
#elif defined(ARDUINO_AVR_UNO)
#define TOTAL_PINS 16
#define NUM_PWM_PINS 6
#define HAS_EEPROM
#elif ...

Defining the device type and pin map in <device_name>.h

A pin map is used to map the Vpins from the device driver in the EX‑CommandStation to the appropriate physical pins on the EX‑IOExpander device, and therefore defining this in the correct order in the EX‑IOExpander software is critical. It is equally critical to ensure that the correct variant or board macro is used to ensure the correct pin map is used when compiling and uploading the software to the EX‑IOExpander device.

Each unique device needs a file created containing the “BOARD_TYPE” macro definition and the device specific pin map.

Files should be named according to the platform and CPU type eg. “arduino_avr_nano.h” or “arduino_nucleo_f412zg.h”.

As per Pin/Vpin allocation, Vpins are allocated to physical pins in ascending order.

These are the considerations when defining the pin map:

  • All pins available for use must be represented in a logical order to provide the simplest user experience

  • The capability for each pin must be provided according to the Pin capability table

  • The number of defined pins must match “TOTAL_PINS” as defined in “defines.h”

  • The number of pins defined with PWM capability must match “NUM_PWM_PINS” as defined in “defines.h”

Further to this, if the microcontroller utilises internal I2C pullup resistors rather than external, physical resistors, then the I2C pins can be defined to allow these to be disabled via “myConfig.h” (see DISABLE_I2C_PULLUPS).

To use the Arduino Uno as the example, the file “arduino_avr_uno.h” would be created with these contents:

#ifndef ARDUINO_AVR_UNO_H
#define ARDUINO_AVR_UNO_H

#include <Arduino.h>
#include "globals.h"

#define BOARD_TYPE F("Uno")
pinDefinition pinMap[TOTAL_PINS] = {
  {2,DIO},{3,DIOP},{4,DIO},{5,DIOP},{6,DIOP},{7,DIO},
  {8,DIO},{9,DIOP},{10,DIOP},{11,DIOP},{12,DIO},{13,DIO},
  {A0,AIDIO},{A1,AIDIO},{A2,AIDIO},{A3,AIDIO},
};
#define I2C_SDA A4
#define I2C_SCL A5

#endif

  • All C++ header (.h) files should include a header guard, which is the first two lines, and file “#ifdef”

  • You must include the Arduino library and “globals.h” file

  • The “BOARD_TYPE” is displayed in the serial console at startup as “Uno”

  • All available pins are defined with their capability

  • Arduino Nano uses internal I2C pullup resistors, and therefore defining the I2C pins A4/A5 allows these to be disabled via “myConfig.H” if desired

Pin capability table

When defining the capabilities available for a specific pin, one of these macros from this table must be utilised. These capability macros are defined in “defines.h”.

This ensures attempting to use a pin for something it’s not capable of will generate an error rather than try to drive a pin with capability that is not possible, as depending on the scenario, this may let the magic smoke out.

Table 37 Pin capability table

Macro

Capabilities

NA

Not suitable for use

DI

Digital input only

DO

Digital output only

DIO

Digital input and output

AI

Analogue input only

AIDI

Analogue and digital input

AIDO

Analogue input and digital output

AIDIO

Analogue input with digital input and output

P

PWM output only

DIP

Digital input and PWM output

DOP

Digital output and PWM output

DIOP

Digital input and output with PWM output

AIP

Analogue input and PWM output

AIDIP

Analogue input with digital input and PWM output

AIDOP

Analogue input with digital output and PWM output

AIDIOP

Analogue input with digital input and output and PWM output

Including the device specific file in EX-IOExpander.ino