W78E052DDG Nuvoton Technology Corporation of America, W78E052DDG Datasheet - Page 13

• Manufacturer Part Number: W78E052DDG
• Description: IC MCU 8-BIT 8K FLASH 40-DIP
• Manufacturer: Nuvoton Technology Corporation of America
• Series: W78r

Specifications of W78E052DDG

• Core Processor: 8052
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: EBI/EMI, UART/USART
• Peripherals: POR, WDT
• Number Of I /o: 36
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2.4 V ~ 5.5 V
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 40-DIP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Data Converters: -

W78E054D/W78E052D/W78E051D Data Sheet
7.6 Data Pointers
The data pointer of W78E054D/W78E052D/W78E051D series is same as standard 8052 that have
one 16-bit Data Pointer (DPTR).
7.7
Architecture
The W78E054D/W78E052D/W78E051D series are based on the standard 8052 device. It is built
around an 8-bit ALU that uses internal registers for temporary storage and control of the peripheral
devices. It can execute the standard 8052 instruction set.
7.7.1 ALU
The ALU is the heart of the W78E054D/W78E052D/W78E051D series. It is responsible for the arith-
metic and logical functions. It is also used in decision making, in case of jump instructions, and is also
used in calculating jump addresses. The user cannot directly use the ALU, but the Instruction Decoder
reads the op-code, decodes it, and sequences the data through the ALU and its associated registers
to generate the required result. The ALU mainly uses the ACC which is a special function register
(SFR) on the chip. Another SFR, namely B register is also used Multiply and Divide instructions. The
ALU generates several status signals which are stored in the Program Status Word register (PSW).
7.7.2 Accumulator
The Accumulator (ACC) is the primary register used in arithmetic, logical and data transfer operations
in the W78E054D/W78E052D/W78E051D series. Since the Accumulator is directly accessible by the
CPU, most of the high speed instructions make use of the ACC as one argument.
7.7.3 B Register
This is an 8-bit register that is used as the second argument in the MUL and DIV instructions. For all
other instructions it can be used simply as a general purpose register.
7.7.4 Program Status Word
This is an 8-bit SFR that is used to store the status bits of the ALU. It holds the Carry flag, the Auxiliary
Carry flag, General purpose flags, the Register Bank Select, the Overflow flag, and the Parity flag.
7.7.5 Scratch-pad RAM
The W78E054D/W78E052D/W78E051D series has a 256 byte on-chip scratch-pad RAM. This can be
used by the user for temporary storage during program execution. A certain section of this RAM is bit
addressable, and can be directly addressed for this purpose.
7.7.6 Stack Pointer
The W78E054D/W78E052D/W78E051D series has an 8-bit Stack Pointer which points to the top of
the Stack. This stack resides in the Scratch Pad RAM in the W78E054D/W78E052D/W78E051D.
Hence the size of the stack is limited by the size of this RAM.
Publication Release Date: Dec 29, 2009
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Revision A09