ST72314J4 STMicroelectronics, ST72314J4 Datasheet - Page 23

• Manufacturer Part Number: ST72314J4
• Description: 8-BIT MCU WITH SINGLE VOLTAGE FLASH MEMORY,ADC, 16-BIT TIMERS, SPI, SCI INTERFACES
• Manufacturer: STMicroelectronics

Specifications of ST72314J4

• Clock Sources: crystal/ceramic resonator oscillators or RC oscillators, external clock, backup Clock Security System
• 4 Power Saving Modes: Halt, Active-Halt, Wait and Slow
• Two 16-bit Timers With: 2 input captures (only one on timer A), 2 output compares (only one on timer A), External clock input on timer A, PWM and Pulse generator modes

8 CENTRAL PROCESSING UNIT
8.1 INTRODUCTION
This CPU has a full 8-bit architecture and contains
six internal registers allowing efficient 8-bit data
manipulation.
8.2 MAIN FEATURES
8.3 CPU REGISTERS
The 6 CPU registers shown in
present in the memory mapping and are accessed
by specific instructions.
Figure 10. CPU Registers
63 basic instructions
Fast 8-bit by 8-bit multiply
17 main addressing modes
Two 8-bit index registers
16-bit stack pointer
Low power modes
Maskable hardware interrupts
Non-maskable software interrupt
RESET VALUE = STACK HIGHER ADDRESS
RESET VALUE = RESET VECTOR @ FFFEh-FFFFh
15
15
RESET VALUE = 1
PCH
8
8 7
RESET VALUE = XXh
RESET VALUE = XXh
RESET VALUE = XXh
7
7
7
7
1
7
1 1 X 1 X X
1 1 H I
Figure 10
PCL
N Z
are not
0
0
0
0
X
0
C
0
Accumulator (A)
The Accumulator is an 8-bit general purpose reg-
ister used to hold operands and the results of the
arithmetic and logic calculations and to manipulate
data.
Index Registers (X and Y)
In indexed addressing modes, these 8-bit registers
are used to create either effective addresses or
temporary storage areas for data manipulation.
(The Cross-Assembler generates a precede in-
struction (PRE) to indicate that the following in-
struction refers to the Y register.)
The Y register is not affected by the interrupt auto-
matic procedures (not pushed to and popped from
the stack).
Program Counter (PC)
The program counter is a 16-bit register containing
the address of the next instruction to be executed
by the CPU. It is made of two 8-bit registers PCL
(Program Counter Low which is the LSB) and PCH
(Program Counter High which is the MSB).
X INDEX REGISTER
Y INDEX REGISTER
ACCUMULATOR
PROGRAM COUNTER
CONDITION CODE REGISTER
STACK POINTER
ST72334J/N, ST72314J/N, ST72124J
X = Undefined Value
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