ST72T774J9B1 STMicroelectronics, ST72T774J9B1 Datasheet - Page 15

• Manufacturer Part Number: ST72T774J9B1
• Manufacturer: STMicroelectronics

Specifications of ST72T774J9B1

• Cpu Family: ST7
• Device Core Size: 8b
• Frequency (max): 24MHz
• Interface Type: I2C/USB
• Program Memory Type: EPROM
• Program Memory Size: 60KB
• Total Internal Ram Size: 1KB
• # I/os (max): 31
• Number Of Timers - General Purpose: 1
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 4V
• On-chip Adc: 1-chx8-bit
• On-chip Dac: 1-chx8-bit
• Instruction Set Architecture: CISC
• Operating Temp Range: 0C to 70C
• Operating Temperature Classification: Commercial
• Mounting: Through Hole
• Pin Count: 42
• Package Type: SPDIP
• Lead Free Status / Rohs Status: Specific Sites Compliant

2 CENTRAL PROCESSING UNIT
2.1 INTRODUCTION
This CPU has a full 8-bit architecture and contains
six internal registers allowing efficient 8-bit data
manipulation.
2.2 MAIN FEATURES
2.3 CPU REGISTERS
The 6 CPU registers shown in
present in the memory mapping and are accessed
by specific instructions.
Accumulator (A)
Figure 5. 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
1
7
7
1 1 X 1 X X
1 1 H I
Figure 5
PCL
N Z
are not
0
0
0
0
X
0
0
C
The Accumulator is an 8-bit general purpose
register 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
instruction (PRE) to indicate that the following
instruction refers to the Y register.)
The Y register is not affected by the interrupt
automatic 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).
ACCUMULATOR
X INDEX REGISTER
Y INDEX REGISTER
PROGRAM COUNTER
CONDITION CODE REGISTER
STACK POINTER
ST72774/ST727754/ST72734
X = Undefined Value
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