ST7LITEU09 STMicroelectronics, ST7LITEU09 Datasheet - Page 28

• Manufacturer Part Number: ST7LITEU09
• Description: ST7ULTRALITE - 8-BIT MCU WITH 2K SINGLE VOLTAGE FLASH MEMORY, ADC, TIMERS
• Manufacturer: STMicroelectronics

Specifications of ST7LITEU09

• 2k Bytes Single Voltage Flash Program Memory With Read-out Protection, In-circuit And In-application Programming (icp And Iap). 10k Write/erase Cycles Guaranteed, Data Retention: 20 years at 55°C
• 128 Bytes Data Eeprom. 300k Write/erase Cycles Guaranteed, Data Retention: 20 years at 55°C
• Clock Sources: internal trimmable 8MHz RC oscillator, internal low power, low frequency RC oscillator or external clock
• Five Power Saving Modes: Halt, Auto Wake Up from Halt, Active-Halt, Wait and Slow
• One 8-bit Lite Timer (lt) With Prescaler Including: watchdog, 1 realtime base and 1 input capture

Central processing unit
6
6.1
6.2
6.3
6.3.1
6.3.2
6.3.3
28/139
Central processing unit
Introduction
This CPU has a full 8-bit architecture and contains six internal registers allowing efficient 8-
bit data manipulation.
Main features
●
●
●
●
●
●
●
●
CPU registers
The six CPU registers shown in
accessed by specific instructions.
Accumulator (A)
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).
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
Figure 11
are not present in the memory mapping and are
ST7LITEU05 ST7LITEU09