C51: Little-Endian CAN Registers, Big-Endian Compiler

Information in this article applies to:

• C51 Version 5.50 and later

QUESTION

The C51 compiler stores unsigned ints in big-endian format, however, the CAN registers on the C505 are stored in little-endian format. Is there a way to make the compiler store unsigned ints in little-endian format so I can write to the 16-bit CAN registers?

ANSWER

The C166 family stores 16-bit values in little-endian format. When the CAN peripheral was copied over to the 8051 devices, the registers were left in the same format, however, the architecture of 8051s is big-endian.

There is no way to make the compiler store unsigned ints in little-endian format, so the CAN registers have to be loaded in single bytes, high and low.

MORE INFORMATION

• Refer to E. Byte Ordering in the Cx51 User's Guide.

Last Reviewed: Thursday, February 25, 2021