CANpro/104 User Manual

PeliCAN vs BasicCAN Addressing Modes

The SJA1000 can operate in 2 different modes, the PeliCAN mode which has extended features and additional registers and which consume 128 bytes of address space per device (there are 2 devices on this board). And, the BasicCAN mode which has reduced functionality but only consumes 32 bytes of register space per device.

Note: The mode of operation of the SJA1000 is performed by changing Bit-7 of the Clock Divider Register (which defaults to BasicCAN mode whenever a PC/104 Bus Reset occurs).

When the SJA1000’s are operated in BasicCAN mode, it is desirable to accommodate the smaller number of registers by decoding a smaller amount of I/O Space (because the I/O Space region is limited in total size).

The selection of Addressing Mode is done with Jumper J3C Position #2. This selection has no meaning when Memory Space operation is enabled (see Jumper J3A above).

J3C Position #2

Function

Removed

PeliCAN Addressing mode enabled

Installed

BasicCAN Addressing mode enabled

Table 7

 

Addressing Examples

Example #1: Memory Address 0x4A6000 (this address is above the 1-Meg boundary) 0x4A6000 = 0100.1010.011X.XXXX.CJJJ.JJJJ (binary)

Address bits in red are matched against their respective Jumper settings. X = Address bits that are ignored by the board.

C = Address bit that is used to select the SJA1000 controller. J = Address bits that are used to select the SJA1000 registers.

Address

Bit

J3A or J3B

Installed

Bit

Value

Position

or Removed

23

0

J3A-2

Removed

22

1

J3A-3

Installed

21

0

Address Bit always decoded as “0”

20

0

Address Bit always decoded as “0”

19

1

J3A-4

Installed

18

0

J3A-5

Removed

17

1

J3A-6

Installed

16

0

J3B-1

Removed

15

0

J3B-2

Removed

14

1

J3B-3

Installed

13

1

J3B-4

Installed

Table 8

CTIM-00043 (0.01) 1/15/2010

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Connect Tech CTIM-00043 user manual PeliCAN vs BasicCAN Addressing Modes, Addressing Examples, J3C Position #2 Function