Now, setNodeId does change TPDO and RPDO CobId without testing previous CobId in order to avoid confusion. Standard does not says when 'default value' should be applied. See DS301 - Object 1400h - 15FFh: Receive PDO Communication Parameter page 108.

/* 
Define the i/o port global symbol 
*/

.globl _io_ports
_io_ports=0x0000	
	
/* 
0x0000 is the default mapping at reset. (it is 0x1000 for 68hc11)
*/