CPC–XT is a short plug-in board for the CAN bus. Due to the possibility of application in 8 bit slots and the compact structure CPC–XT can also be used in space restricted conditions. CPC–XT was designed for industrial series application and has a robust a cost efficient construction. CPC–XT supports different types of CAN controllers, the full CAN controller Intel AN82527 as well as the basic CAN controller NXP SJA1000.
CPC–XT maps the CAN controller registers directly into the PC address space and thus allows access to CAN messages with low latency. Existing software for the supported CAN controllers can easily be adapted. The CAN communication with CPC–XT may be handled either in interrupt controlled mode or in polled mode, interrupt channels 3 – 7 are available.
CPC–XT can optionally be delivered with galvanic separation to the CAN bus. In this case the power supply for the transceiver runs across the CAN bus (option GTB) or a DC/DC converter (option GTI).
| Pin assignment | Connector D-Sub 9 complying to CiA DS-102 |
|---|---|
| Type of the physical connection | ISO 11898 / Transceiver PCA82C251 |
| Maximum voltage on bus pins | ±30V referring to bus ground |
| Isolation voltage with galvanic separation | ±500V |
The configuration of the address space and the interrupt channel is done by jumpers:
| Resource | Parameter |
|---|---|
| Base address in PC memory | 1 kByte in the range C0000h –FFFFFh, adjustable in steps of 1kByte |
| PC Interrupt channel | One interrupt within range 3 – 7 |
CPC–XT is mapped into the memory space of the PC with a base address in the area from C0000h to DE000h and occupies 512 bytes. Through the availability of the CAN controller in the memory address space the CAN communication takes place directly and with low latency time.
The memory occupied by CPC–XT is devided into two subranges. The first subrange encloses the configuration registers of the card and begins at the base address. The second subrange allows the access to the CAN controller and has 100h bytes offset to the base address.