CAN Checked – CFE18 – CANbus Function Extender

CFE18 stands for “Can Bus Function Extension” or colloquially also “Can Switch Board” – why is this module needed?

Can bus connections in the vehicle sometimes pose great challenges for our customers. Especially in motorsport applications, when electronics have to be housed in the steering wheel and information from adjustment knobs (trimpots) or push buttons is then to be transmitted via Can Bus.

CANchecked now offers a small additional module with 18 connections: 9 for push buttons and 9 for analog inputs (0-5V signal).

Tested with:
– MaxxECU
– Ecumaster (EMUB and PMU)
– LinkECU
– Haltech (emulates an IO Expander A + B or just B)
– Emtron

This device is also available with a housing:  CFE18 – can switch board

– The CFE18 hardware –

With only 29x27mm, the board is kept very compact and can be placed anywhere. The pin spacing is 2.54mm – for the power supply, for safety reasons, 3.81mm.

We have made a hole for fastening, which can be used as a screw connection.

A solder jumper is attached to the circuit board.

If you close this, the Can Bus termination with 120 Ohm is active. The solder jumper is OPEN by default .

– Connections –

– Motorsport steering wheel –

– Connection options –

Switches and trimpots (adjustment buttons) can be connected to the CFE18.

But sensors such as oil pressure, fuel pressure, boost pressure, exhaust back pressure and integration in a separate housing would also be possible.

– CFE18 connection / Default Can Bus Stream –

– AIN smoothing –

* From software version 3

If the analog inputs fluctuate too much, they can be smoothed using software. This can be configured separately for each analog input.

The analog inputs are evaluated with each transmission (default: 20Hz).

If, for example, a smoothing factor of 4 is set, the average of the last 16 measurements is taken. This makes the value quieter (smoother), but also reacts more slowly to fluctuations. Here you have to find a healthy middle ground to suit your sensors and application.

The setting is made via Can Bus – see ” Configuration options ”

– Configuration options –

**Specify your ECU at checkout and we’ll configure your device before shipping**

The following values ​​can be adjusted via Can Bus:

* from software version 3

Byte 0 + 1 are always 0x0C and 0x0A
Byte 2 Feature beginning with 0x0A

Features:
can id: 0x0A (high byte) + 0x0B (low byte)
config can id: 0x0C (high byte) + 0x0D (low byte)
frequency: 0x0E
can bus speed: 0x0F
mode: 0x10

Example 1: change data can id to 0x600

Example 2: change frequency to 50Hz (20ms = 0x14 in hex)

Example 3: change can bus speed to 1Mbit

Example 4: change mode to EMUv3

Example 5: change smooting on AIN1 to 4 (= 16)

(0x20 = AIN1, 0x21 = AIN2, 0x22 = AIN3 …, 0x28 = AIN8)

– Control unit / ECU configuration –

**Specify your ECU at checkout and we’ll configure your device before shipping**

The analog inputs provide 10-bit resolution and thus values ​​from 0 to 1023. The value must be converted in the control unit. All values ​​are “unsigned big endian”

Examples:
5V voltage AIN0
0x700 Byte0 + 1
multiplier: 5; Divisor: 1023; Offset: 0

or multiplier: 0.004887585533

Exhaust gas temperature (type k) AIN7:
0x702 Byte6 + 7
multiplier: 1250; Divisor: 1023; Offset: 0

or multiplier: 1.2218963832

Either the individual bytes are used for the digital inputs. Eg DIN6: 0x702 byte 6 or the bit mask at 0x702 byte2

eg DIN6: 0x702 Byte2 Mask: 0x40

– Documentation / download –

You can also download this page as a PDF here:

• CFE18 manual (GERMAN / ENGLISH)
• Drawing (DXF, STP)
• CFE18 TRI file
• CFE18 DBC file