ATMEGA48-20PU Atmel, ATMEGA48-20PU Datasheet - Page 245

IC AVR MCU 4K 20MHZ 5V 28DIP

ATMEGA48-20PU

Manufacturer Part Number
ATMEGA48-20PU
Description
IC AVR MCU 4K 20MHZ 5V 28DIP
Manufacturer
Atmel
Series
AVR® ATmegar
Datasheets

Specifications of ATMEGA48-20PU

Core Processor
AVR
Core Size
8-Bit
Speed
20MHz
Connectivity
I²C, SPI, UART/USART
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Number Of I /o
23
Program Memory Size
4KB (2K x 16)
Program Memory Type
FLASH
Eeprom Size
256 x 8
Ram Size
512 x 8
Voltage - Supply (vcc/vdd)
2.7 V ~ 5.5 V
Data Converters
A/D 6x10b
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
28-DIP (0.300", 7.62mm)
Processor Series
ATMEGA48x
Core
AVR8
Data Bus Width
8 bit
Data Ram Size
512 B
Interface Type
2-Wire/SPI/USART/Serial
Maximum Clock Frequency
20 MHz
Number Of Programmable I/os
23
Number Of Timers
3
Operating Supply Voltage
2.7 V to 5.5 V
Maximum Operating Temperature
+ 85 C
Mounting Style
Through Hole
3rd Party Development Tools
EWAVR, EWAVR-BL
Development Tools By Supplier
ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT
Minimum Operating Temperature
- 40 C
On-chip Adc
6-ch x 10-bit
Cpu Family
ATmega
Device Core
AVR
Device Core Size
8b
Frequency (max)
20MHz
Total Internal Ram Size
512Byte
# I/os (max)
23
Number Of Timers - General Purpose
3
Operating Supply Voltage (typ)
3.3/5V
Operating Supply Voltage (max)
5.5V
Operating Supply Voltage (min)
2.7V
Instruction Set Architecture
RISC
Operating Temp Range
-40C to 85C
Operating Temperature Classification
Industrial
Mounting
Through Hole
Pin Count
28
Package Type
PDIP
For Use With
ATSTK600-TQFP32 - STK600 SOCKET/ADAPTER 32-TQFPATSTK600 - DEV KIT FOR AVR/AVR32770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAGATAVRDRAGON - KIT DRAGON 32KB FLASH MEM AVRATAVRISP2 - PROGRAMMER AVR IN SYSTEMATJTAGICE2 - AVR ON-CHIP D-BUG SYSTEM
Lead Free Status / RoHS Status
Lead free / RoHS Compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
ATMEGA48-20PU
Manufacturer:
ATMEL
Quantity:
42
Part Number:
ATMEGA48-20PU
Manufacturer:
Microchip Technology
Quantity:
801
23.3
2545S–AVR–07/10
Starting a Conversion
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 disabling the Power Reduction ADC bit, PRADC, in
Power Consumption” on page 40
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 per-
forming 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.
Figure 23-2. ADC Auto Trigger Logic
Using the ADC Interrupt Flag as a trigger source makes the ADC start a new conversion as soon
as the ongoing conversion has finished. The ADC then operates in Free Running mode, con-
stantly sampling and updating the ADC Data Register. The first conversion must be started by
writing a logical one to the ADSC bit in ADCSRA. In this mode the ADC will perform successive
conversions independently of whether the ADC Interrupt Flag, ADIF is cleared or not.
ADSC
SOURCE n
ADIF
SOURCE 1
.
.
.
.
ADTS[2:0]
DETECTOR
by writing a logical zero to it and writing a logical one to the
EDGE
ADATE
START
ATmega48/88/168
CONVERSION
PRESCALER
LOGIC
CLK
“Minimizing
ADC
245

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