ATTINY25-15MZ Atmel, ATTINY25-15MZ Datasheet - Page 113
![MCU AVR 2K FLASH 15MHZ 20-QFN](/photos/30/99/309923/qfn-20_sml.jpg)
ATTINY25-15MZ
Manufacturer Part Number
ATTINY25-15MZ
Description
MCU AVR 2K FLASH 15MHZ 20-QFN
Manufacturer
Atmel
Series
AVR® ATtinyr
Datasheet
1.ATTINY25-15MZ.pdf
(196 pages)
Specifications of ATTINY25-15MZ
Package / Case
20-QFN
Voltage - Supply (vcc/vdd)
2.7 V ~ 5.5 V
Operating Temperature
-40°C ~ 125°C
Speed
16MHz
Number Of I /o
6
Eeprom Size
128 x 8
Core Processor
AVR
Program Memory Type
FLASH
Ram Size
128 x 8
Program Memory Size
2KB (2K x 8)
Data Converters
A/D 4x10b
Oscillator Type
Internal
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Connectivity
USI
Core Size
8-Bit
Processor Series
ATTINY2x
Core
AVR8
Data Bus Width
8 bit
Data Ram Size
128 B
Interface Type
UART, SPI, USI
Maximum Clock Frequency
16 MHz
Number Of Programmable I/os
6
Number Of Timers
2
Maximum Operating Temperature
+ 85 C
Mounting Style
SMD/SMT
3rd Party Development Tools
EWAVR, EWAVR-BL
Development Tools By Supplier
ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT
Minimum Operating Temperature
- 40 C
On-chip Adc
10 bit, 4 Channel
Data Rom Size
128 B
A/d Bit Size
10 bit
A/d Channels Available
4
Height
0.75 mm
Length
4 mm
Supply Voltage (max)
5.5 V
Supply Voltage (min)
2.7 V
Width
4 mm
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
18.3
7598H–AVR–07/09
Starting a Conversion
If ADC0 or ADC2 is selected as both the positive and negative input to the differential gain
amplifier (ADC0-ADC0 or ADC2-ADC2), the remaining offset in the gain stage and conversion
circuitry can be measured directly as the result of the conversion. This figure can be subtracted
from subsequent conversions with the same gain setting to reduce offset error to below 1 LSW.
The on-chip temperature sensor is selected by writing the code “1111” to the MUX3..0 bits in
ADMUX register when the ADC4 channel is used as an ADC input.
The ADC is enabled by setting the ADC Enable bit, ADEN in ADCSRA. Voltage reference and
input channel selections will not go into effect until ADEN is set. The ADC does not consume
power when ADEN is cleared, so it is recommended to switch off the ADC before entering power
saving sleep modes.
The ADC generates a 10-bit result which is presented in the ADC Data Registers, ADCH and
ADCL. By default, the result is presented right adjusted, but can optionally be presented left
adjusted by setting the ADLAR bit in ADMUX.
If the result is left adjusted and no more than 8-bit precision is required, it is sufficient to read
ADCH. Otherwise, ADCL must be read first, then ADCH, to ensure that the content of the data
registers belongs to the same conversion. Once ADCL is read, ADC access to data registers is
blocked. This means that if ADCL has been read, and a conversion completes before ADCH is
read, neither register is updated and the result from the conversion is lost. When ADCH is read,
ADC access to the ADCH and ADCL Registers is re-enabled.
The ADC has its own interrupt which can be triggered when a conversion completes. When ADC
access to the data registers is prohibited between reading of ADCH and ADCL, the interrupt will
trigger even if the result is lost.
A single conversion is started by writing a logical one to the ADC Start Conversion bit, ADSC.
This bit stays high as long as the conversion is in progress and will be cleared by hardware
when the conversion is completed. If a different data channel is selected while a conversion is in
progress, the ADC will finish the current conversion before performing the channel change.
Alternatively, a conversion can be triggered automatically by various sources. Auto Triggering is
enabled by setting the ADC Auto Trigger Enable bit, ADATE in ADCSRA. The trigger source is
selected by setting the ADC Trigger Select bits, ADTS in ADCSRB (see description of the ADTS
bits for a list of the trigger sources). When a positive edge occurs on the selected trigger signal,
the ADC prescaler is reset and a conversion is started. This provides a method of starting con-
versions at fixed intervals. If the trigger signal still is set when the conversion completes, a new
conversion will not be started. If another positive edge occurs on the trigger signal during con-
version, the edge will be ignored. Note that an Interrupt Flag will be set even if the specific
interrupt is disabled or the Global Interrupt Enable bit in SREG is cleared. A conversion can thus
be triggered without causing an interrupt. However, the Interrupt Flag must be cleared in order to
trigger a new conversion at the next interrupt event.
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