CAN2USB adaptor Project of Uri Kogan ( ) Under supervision of Konstantin Siniuk

Introduction  Technion is developing access control mechanism.  Doors are interconnected using CAN bus.  Database management and the control itself are done on regular PCs using special software.  Needed connection between CAN and PC.

Introduction (continued)  Interconnection options: –Serial (RS232). –Parallel. –Modern options: FireWire, USB, Wireless.

Why USB? Why CAN? USB  Serial and parallel are old and slow.  Supports high-bandwidth (up to 400MBit/s).  Supported by most operating systems (Windows, Unix) and hardware.  Relatively simple. CAN  Standard protocol for industrial networks.  Long distances.  Multiple-devices on one bus.

Project Goals 1.Main goal is to develop a bridge access control devices and PC.  Hardware design.  Software design. 2.Provide transparent communication between access control devices and PC.

Basics CAN USB

What do I build? CAN2USB CAN bus

Block diagram of the card MCU Zilog 512kBytes RAM MCU Microchip USB Controller CAN Channel 1 CAN Channel 2 CAN Channel 3 CAN Channel 4 CAN Channel 5 Power Supply Serial Communication (RS232)

Technology  Primary MCU: Zilog Z8 Encore!® family –64 kBytes FLASH –4 kBytes RAM –SPI –DMA  Secondary MCU: Microchip PIC18F452 –16 kWord FLASH –1.5 kBytes RAM –SPI –USART

Technology  USB: National USB1.1 compatible.  CAN: –Microchip CAN controller, MCP2510. –Microchip CAN transceiver, MCP2551.  RAM: 512 kBytes, ST Microelectronics, M68AW511AL  Serial: standard MAX232  Power: LM , LM

Baud Rates  Maximal data transfer rate of CAN bus in ideal conditions is 1 Mbit/sec.  SPI throughput of MCU’s: ~3 Mbit/sec.  Maximal data transfer rate of USB1.1 in full speed mode is 11 Mbit/sec.  Since CAN conditions are not ideal and bus isn’t fully loaded, 5 CAN buses will work on one SPI bus.

The Scheme Itself

Time table  25 Nov Card design.  25 Dec Card testing with basic software.  15 Jan Card testing in real conditions.  25 Jan Fully operational card.