Features
•
High-performance, Low-power AVR
®
8-bit Microcontroller
•
Advanced RISC Architecture
– 90 Powerful Instructions – Most Single Clock Cycle Execution
– 32 x 8 General Purpose Working Registers
– Fully Static Operation
Non-volatile Program and Data Memories
– 1K Byte In-System Programmable Flash Program Memory
Endurance: 1,000 Write/Erase Cycles
– 64 Bytes EEPROM
Endurance: 100,000 Write/Erase Cycles
– Programming Lock for Flash Program Data Security
Peripheral Features
– Interrupt and Wake-up on Pin Change
– Two 8-bit Timer/Counters with Separate Prescalers
– One 150 kHz, 8-bit High-speed PWM Output
– 4-channel 10-bit ADC
One Differential Voltage Input with Optional Gain of 20x
– On-chip Analog Comparator
– Programmable Watchdog Timer with On-chip Oscillator
Special Microcontroller Features
– In-System Programmable via SPI Port
– Enhanced Power-on Reset Circuit
– Programmable Brown-out Detection Circuit
– Internal, Calibrated 1.6 MHz Tunable Oscillator
– Internal 25.6 MHz Clock Generator for Timer/Counter
– External and Internal Interrupt Sources
– Low-power Idle and Power-down Modes
Power Consumption at 1.6 MHz, 3V, 25°C
– Active: 3.0 mA
– Idle Mode: 1.0 mA
– Power-down: < 1 µA
I/O and Packages
– 8-lead PDIP and 8-lead SOIC: 6 Programmable I/O Lines
Operating Voltages
– 2.7V - 5.5V
Internal 1.6 MHz System Clock
•
•
8-bit
Microcontroller
with 1K Byte
Flash
ATtiny15L
•
•
•
•
•
Pin Configuration
PDIP/SOIC
(RESET/ADC0) PB5
(ADC3) PB4
(ADC2) PB3
GND
1
2
3
4
8
7
6
5
VCC
PB2 (ADC1/SCK/T0/INT0)
PB1 (AIN1/MISO/OC1A)
PB0 (AIN0/AREF/MOSI)
Not recommended for new
design
Rev. 1187H–AVR–09/07
1
Description
The ATtiny15L is a low-power CMOS 8-bit microcontroller based on the AVR RISC
architecture. By executing powerful instructions in a single clock cycle, the ATtiny15L
achieves throughputs approaching 1 MIPS per MHz allowing the system designer to
optimize power consumption versus processing speed.
The AVR core combines a rich instruction set with 32 general purpose working registers.
All the 32 registers are directly connected to the Arithmetic Logic Unit (ALU), allowing
two independent registers to be accessed in one single instruction executed in one clock
cycle. The resulting architecture is more code efficient while achieving throughputs up to
ten times faster than conventional CISC microcontrollers.
The ATtiny15L provides 1K byte of Flash, 64 bytes EEPROM, six general purpose I/O
lines, 32 general purpose working registers, two 8-bit Timer/Counters, one with high-
speed PWM output, internal Oscillators, internal and external interrupts, programmable
Watchdog Timer, 4-channel 10-bit Analog-to-Digital Converter with one differential volt-
age input with optional 20x gain, and three software-selectable Power-saving modes.
The Idle mode stops the CPU while allowing the ADC, anAlog Comparator,
Timer/Counters and interrupt system to continue functioning. The ADC Noise Reduction
mode facilitates high-accuracy ADC measurements by stopping the CPU while allowing
the ADC to continue functioning. The Power-down mode saves the register contents but
freezes the Oscillators, disabling all other chip functions until the next interrupt or Hard-
ware Reset. The wake-up or interrupt on pin change features enable the ATtiny15L to
be highly responsive to external events, still featuring the lowest power consumption
while in the Power-saving modes.
The device is manufactured using Atmel’s high-density, Non-volatile memory technol-
ogy. By combining a RISC 8-bit CPU with Flash on a monolithic chip, the ATtiny15L is a
powerful microcontroller that provides a highly flexible and cost-efficient solution to
many embedded control applications. The peripheral features make the ATtiny15L par-
ticularly suited for battery chargers, lighting ballasts and all kinds of intelligent sensor
applications.
The ATtiny15L AVR is supported with a full suite of program and system development
tools including macro assemblers, program debugger/simulators, In-circuit emulators
and evaluation kits.
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ATtiny15L
1187H–AVR–09/07
ATtiny15L
Block Diagram
Figure 1.
The ATtiny15L Block Diagram
VCC
8-BIT DATA BUS
INTERNAL
OSCILLATOR
GND
PROGRAM
COUNTER
STACK
POINTER
WATCHDOG
TIMER
TIMING AND
CONTROL
TUNABLE
INTERNAL
OSCILLATOR
PROGRAM
FLASH
HARDWARE
STACK
MCU CONTROL
REGISTER
INSTRUCTION
REGISTER
GENERAL
PURPOSE
REGISTERS
MCU STATUS
REGISTER
INSTRUCTION
DECODER
Z
TIMER/
COUNTER0
CONTROL
LINES
ALU
TIMER/
COUNTER1
STATUS
REGISTER
INTERRUPT
UNIT
PROGRAMMING
LOGIC
ISP MODULE
DATA
EEPROM
ANALOG MUX
ADC
ANALOG
COMPARATOR
DATA REGISTER
PORT B
DATA DIR.
REG.PORT B
+
-
PORT B DRIVERS
PB0-PB5
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1187H–AVR–09/07
Pin Descriptions
VCC
GND
Port B (PB5..PB0)
Supply voltage pin.
Ground pin.
Port B is a 6-bit I/O port. PB4..0 are I/O pins that can provide internal pull-ups (selected
for each bit). PB5 is input or open-drain output. The use of pin PB5 is defined by a fuse
and the special function associated with this pin is External Reset. The port pins are tri-
stated when a reset condition becomes active, even if the clock is not running.
Port B also accommodates analog I/O pins. The Port B pins with alternate functions are
shown in Table 1.
Table 1.
Port B Alternate Functions
Port Pin
PB0
Alternate Function
MOSI (Data Input Line for Memory Downloading)
AREF (ADC Voltage Reference)
AIN0 (Analog Comparator Positive Input)
MISO (Data Output Line for Memory Downloading)
OC1A (Timer/Counter PWM Output)
AIN1 (Analog Comparator Negative Input)
SCK (Serial Clock Input for Serial Programming)
INT0 (External Interrupt0 Input)
ADC1 (ADC Input Channel 1)
T0 (Timer/Counter0 External Counter Input)
ADC2 (ADC Input Channel 2)
ADC3 (ADC Input Channel 3)
RESET (External Reset Pin)
ADC0 (ADC Input Channel 0)
PB1
PB2
PB3
PB4
PB5
Analog Pins
Up to four analog inputs can be selected as inputs to Analog-to-Digital Converter (ADC).
The internal Oscillator provides a clock rate of nominally 1.6 MHz for the system clock
(CK). Due to large initial variation (0.8 -1.6 MHz) of the internal Oscillator, a tuning capa-
bility is built in. Through an 8-bit control register – OSCCAL – the system clock rate can
be tuned with less than 1% steps of the nominal clock.
There is an internal PLL that provides a 16x clock rate locked to the system clock (CK)
for the use of the Peripheral Timer/Counter1. The nominal frequency of this peripheral
clock, PCK, is 25.6 MHz.
Internal Oscillators
4
ATtiny15L
1187H–AVR–09/07
ATtiny15L
ATtiny15L
Architectural
Overview
The fast-access Register File concept contains 32 x 8-bit general purpose working reg-
isters with a single-clock-cycle access time. This means that during one single clock
cycle, one ALU (Arithmetic Logic Unit) operation is executed. Two operands are output
from the Register File, the operation is executed, and the result is stored back in the
Register File – in one clock cycle.
Two of the 32 registers can be used as a 16-bit pointer for indirect memory access. This
pointer is called the Z-pointer, and can address the Register File, IO file and the Flash
Program memory.
Figure 2.
The ATtiny15L AVR RISC Architecture
Data Bus 8-bit
Control
Registrers
512 x 16
Program
FLASH
Program
Counter
Status
and Test
Interrupt
Unit
Instruction
Register
Direct Addressing
Instruction
Decoder
32 x 8
General
Purpose
Registrers
SPI Unit
2 x 8-bit
Timer/Counter
Watchdog
Timer
ALU
Control Lines
ADC
64 x 8
EEPROM
Analog
Comparator
I/O Lines
The ALU supports arithmetic and logic functions between registers or between a con-
stant and a register. Single-register operations are also executed in the ALU. Figure 2
shows the ATtiny15L AVR RISC microcontroller architecture. The AVR uses a Harvard
architecture concept with separate memories and buses for program and data memo-
ries. The program memory is accessed with a two-stage pipeline. While one instruction
is being executed, the next instruction is pre-fetched from the program memory. This
concept enables instructions to be executed in every clock cycle. The Program memory
is In-System Programmable Flash memory.
With the relative jump and relative call instructions, the whole address space is directly
accessed. All AVR instructions have a single 16-bit word format, meaning that every
program memory address contains a single 16-bit instruction.
During interrupts and subroutine calls, the return address Program Counter (PC) is
stored on the Stack. The Stack is a 3-level-deep Hardware Stack dedicated for subrou-
tines and interrupts.
The I/O memory space contains 64 addresses for CPU peripheral functions as Control
Registers, Timer/Counters and other I/O functions. The memory spaces in the AVR
architecture are all linear and regular memory maps.
5
1187H–AVR–09/07
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