Cx51 User's Guide
Version 6.0 Differences
EXTERNAL and SEGMENT limitations removed
The number of external symbols and segments per module are no
longer limited to 256. This historical limitation was imposed by
the old Intel Object File format.
First 256 characters of a variable name are
Now the first 256 characters of a variable name are significant.
Previously, only the first 32 characters were significant.
Support for NXP 80C51MX and Dallas Contiguous Mode
Cx51 provides support for the NXP 80C51MX architecture and the
Dallas Contiguous Mode that is available on the Dallas 390 and
OMF2 directive and far memory type support
The OMF2 directive enables generation of
a new OMF file format that provides detailed symbol type checking
across modules and supports up to 16MB code and xdata memory. This
format is required when you use the STRING, VARBANKING, and XCROM
The STRING directive locates constant
strings in xdata const or far const space. This
leaves more code space available for program code.
Assigns user defined class names to compiler generated segments.
Class names may be referenced by the LX51 Linker to locate all
segments with a specific class name.
VARBANKING directive and far memory type support
Two new memory types, far and const far, and user
configurable access routines provide support for up to 16MB
extended code and xdata memory. The VARBANKING directive enables far
memory type support.
The XCROM directive locates constants
into xdata ROM which frees code ROM space for program
Support for Analog Devices B2 series of
The B2 series of ADuC devices contains dual DPTR and an extended
Only the the PK51 Professional Developers Kit supports the OMF2
output file format, NXP 80C51MX, Dallas Contiguous Mode, and
VARBANKING. These options are not available in the CA51 and DK51