OGCAN - CAN interface for OpenGrab EPM

OGCAN

New product

Discontinued

OGCAN is an open hardware CAN bus interface that allows you to control the EPM and to monitor its state via standard CAN bus or via serial CLI. Supported CAN protocols: CANaerospace, UAVCAN.

More details

More info

OGCAN is an open hardware CAN bus interface that allows you to control  the OpenGrab EPM and to monitor its state via CAN bus or serial CLI. CAN protocol is UAVCAN.

OGCAN is built on STMicroelectronics STM32F103 MCU running RTOS ChibiOS, implements one CAN bus interface (ISO 11898-2, up to 1 Mbps), one TTL UART for CLI and optional CAN termination resistor (via jumper). OGCAN can be directly connected to EPM via two board-to-board connectors, as shown below.

Firmware sources and schematics can be found on the github page (prebuilt binaries are available, build/flash instructions are also provided); details on CAN protocol and CLI commands can be found in the datasheet.

Beware: this is experimental developer edition, the design can be changed in future.

Links

Datasheet: https://docs.google.com/document/d/1Ybt6NxST_QbpNfdEGE-l7oGNAbfmcufVGxpM0q9ekjc/pub
Schematic (PDF): https://github.com/pavel-kirienko/opengrab_can/blob/master/hardware/OpenGrab.pdf
Firmware: https://github.com/pavel-kirienko/opengrab_can/tree/master/firmware 

CAN bus connectors pinout

Pin

Wire - twisted pair

Function

1

pair 1 tip (white/blue)

+5 VDC

2

pair 1 ring (blue)

GND

3

pair 2 ring (orange)

CAN H

4

pair 2 tip (white/orange)

CAN L

 

 

Specifications

Parameter

Min

Nom

Max

Unit

Supply voltage

4.5

5.0

5.5

V

Supply current (EPM excluded)

10

30

80

mA

CAN maximum bit rate

 

1

 

Mbit/s

CAN positive-going input threshold voltage

 

750

900

mV

CAN negative-going input threshold voltage

500

650

 

mV

CAN differential output voltage, dominant

1.5

2.0

3.0

V

CAN differential output voltage, recessive

-120

0

12

mV

UART low level input voltage

-0.3

0

1.6

V

UART high level input voltage

2.1

3.3

5.5

V

UART low level output voltage

0

0

0.5

V

UART high level output voltage

2.8

3.3

3.4

V

Free air temperature

-40

 

80

deg C