Maxim Integrated 71M6534 Energy Meter IC Family Software - Manual (Page 43)

71M653X Software User’s Guide
5
5 DEMO CODE DESCRIPTION
5.1 80515 DATA TYPES AND COMPILER-SPECIFIC INFORMATION
5.1.1 Data Types
The 80515 MPU core is an 8-bit micro controller (MPU); thus operations that use 8-bit data types such as “char” or
“unsigned char” work more efficiently than operations that use multi-byte types, such as “int” or “long”. The Keil C51
compiler supports ANSI C data types as well as data types that are unique to the generic 8051 controller family. Table
5-2 lists available data types. Please refer to the Keil Cx51 Compiler User’s Guide for more details.
Various types of address spaces are available for the 80515 MPU core of the 71M653X, and in order to utilize the
various memory space types efficiently, the Demo Code uses variable type definitions (typedefs.) presented in this
chapter.
To understand the data types, it helps to examine the internal data memory map of the 80515 MPU core, as shown in
Table 5-1: .
Address Direct addressing Indirect addressing
0xFF
Special Function Registers
(SFRs)
RAM
0x80
0x7F
Byte-addressable area
0x30
0x2F
Bit-addressable area
0x20
0x1F
Register banks R0…R7
0x00
Table 5-1: Internal Data Memory Map
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