Acrosser AR-B6051 User Manual

Page 49

if( result != 0)

fprintf( stderr, “Fail to receive CAN packets!\n”);

6. Syntax:

i32 getCanMask(struct CanMask *mask)

Description: This function gets the current setting of the acceptance masks. Masks are used to

determine which bits in the ID field of the CAN packet are examined with the filters. There are two

acceptance masks (mask0 and mask1) and six acceptance filters (filter0 ~ filter5) in the CAN Bus

subsystem. Filter0 ~ filter1 are associated with mask0. Filter2 ~ filter4 are associated with mask1.

Here is the Mask/Filter truth table:

Mask bit

Filter bit

Message

ID bit n

Accept or reject bit n

x x

Reject

Note: x = don’t care

Parameters: This parameter ‘mask’ is a pointer to a variable of type ‘CanMask’.

Users use the

field ‘maskId’ to indicate the mask they want and the API put the

setting of the mask in the ‘mask’

field.

struct CanMask {

u8 maskId; // 0 or 1

u32

mask;

}

Return Value: If this function receives the mask setting successfully, it returns 0, any other

returned value stands for error.

For

example:

struct CanMask a_mask;

a_mask.maskId = 0; // indicate the mask0