User manual
mikroPascal PRO for dsPIC30/33 and PIC24
MikroElektronika
261
CANSPI Library
The SPI module is available with a number of the dsPIC30/33 and PIC24 MCUs. The mikroPascal PRO for dsPIC30/33
and PIC24 provides a library (driver) for working with mikroElektronika’s CANSPI Add-on boards (with MCP2515 or
MCP2510) via SPI interface.
The CAN is a very robust protocol that has error detection and signalization, self?checking and fault connement.
Faulty CAN data and remote frames are re-transmitted automatically, similar to the Ethernet.
Data transfer rates depend on distance. For example, 1 Mbit/s can be achieved at network lengths below 40m while
250 Kbit/s can be achieved at network lengths below 250m. The greater distance the lower maximum bitrate that can
be achieved. The lowest bitrate dened by the standard is 200Kbit/s. Cables used are shielded twisted pairs.
CAN supports two message formats:
- Standard format, with 11 identier bits and
- Extended format, with 29 identier bits
In the mikroPascal PRO for dsPIC30/33 and PIC24, each routine of the CAN library has its own CANSPI counterpart
with identical syntax. For more information on Controller Area Network, consult the CAN Library. Note that an effective
communication speed depends on SPI and certainly is slower than “real” CAN.
Important:
- Consult the CAN standard about CAN bus termination resistance.
- An effective CANSPI communication speed depends on SPI and certainly is slower than “real” CAN.
- The library uses the SPI module for communication. User must initialize appropriate SPI module before using the
CANSPI Library.
- For MCUs with multiple SPI modules it is possible to initialize both of them and then switch by using the SPI_Set_
Active routine.
- Number of SPI modules per MCU differs from chip to chip. Please, read the appropriate datasheet before utilizing
this library.
Library Dependency Tree