ATmega3208系列MCU物联网解决方案

　　Microchip公司的ATmega3208/3209/4808/4809是采用AVR®处理器的megaAVR® 0系列MCU，具有工作高达20MHz的硬件乘法器，以及高达48KB闪存储器，6KB SRAM和256B EEPROM，采用最新的技术和灵活的低功率架构，包括事件系统和SleepWalking，精密模拟特性和先进的外设，采用28，32或48引脚封装，主要用在工业，医疗，家庭自动化和物联网（IoT）应用。本文介绍了ATmega3208/3209/4808/4809主要特性， 框图以及开发板AVR-IoT WG主要特性，电路图PCB设计图和材料清单。

　　The ATmega3208/3209/4808/4809 microcontrollers of the megaAVR® 0-series are using the AVR®processor with hardware multiplier， running at up to 20 MHz， with a wide range of Flash sizes up to 48 KB， up to 6 KB of SRAM， and 256 bytes of EEPROM in 28-， 32-， or 48-pin package. The series uses the latest technologies from Microchip with a flexible and low-power architecture including Event System and SleepWalking， accurate analog features and advanced peripherals.

　　The devices described here offer Flash sizes from 32 KB to 48 KB in a 32-pin package.

　　ATmega3208/3209/4808/4809主要特性：

　　• AVR® CPU

　　– Single-cycle I/O access

　　– Two-level interrupt controller

　　– Two-cycle hardware multiplier

　　• Memories

　　– Up to 48 KB In-system self-programmable Flash memory

　　– 256B EEPROM

　　– Up to 6 KB SRAM

　　– Write/Erase endurance：

　　• Flash 10，000 cycles

　　• EEPROM 100，000 cycles

　　– Data retention： 20 Years at 85°C

　　• System

　　– Power-on Reset （POR） circuit

　　– Brown-out Detection （BOD）

　　– Clock options：

　　• 20 MHz low power internal oscillator with fuse-protected frequency setting

　　• 32.768 kHz Ultra Low Power （ULP） internal oscillator

　　• 32.768 kHz external crystal oscillator

　　• External clock input

　　– Single pin Unified Program Debug Interface （UPDI）

　　– Three sleep modes：

　　• Idle with all peripherals running and mode for immediate wake-up time

　　• Standby

　　– Configurable operation of selected peripherals

　　– SleepWalking peripherals

　　• Power Down with limited wake-up functionality

　　• Peripherals

　　– One 16-bit Timer/Counter type A with dedicated period register， three compare channels （TCA）

　　– Three 16-bit Timer/Counter type B with input capture （TCB）

　　– One 16-bit Real Time Counter （RTC） running from external crystal or internal RC oscillator

　　– Three USART with fractional baud rate generator， autobaud， and start-of-frame detection

　　– Master/slave Serial Peripheral Interface （SPI）

　　– Dual mode Master/Slave TWI with dual address match

　　• Standard mode （Sm， 100 kHz）

　　• Fast mode （Fm， 400 kHz）

　　• Fast mode plus （Fm+， 1 MHz）

　　– Event System for CPU independent and predictable inter-peripheral signaling

　　– Configurable Custom Logic （CCL） with up to four programmable Lookup Tables （LUT）

　　– One Analog Comparator （AC） with scalable reference input

　　– One 10-bit 150 ksps Analog to Digital Converter （ADC）

　　– Five selectable internal voltage references： 0.55V， 1.1V， 1.5V， 2.5V， and 4.3V

　　– CRC code memory scan hardware

　　• Optional automatic scan after reset

　　– Watchdog Timer （WDT） with Window Mode， with separate on-chip oscillator

　　– External interrupt on all general purpose pins

　　• I/O and Packages：

　　– 27 programmable I/O lines

　　– 32-pin VQFN 5x5 and TQFP 7x7

　　• Temperature Range： -40°C to 125°C

　　• Speed Grades：

　　– 0-5 MHz @ 1.8V – 5.5V

　　– 0-10 MHz @ 2.7V – 5.5V

　　– 0-20 MHz @ 4.5V – 5.5V， -40°C to 105°C

　　

　　图1. ATmega3208/3209/4808/4809框图

　　开发板AVR-IoT WG

　　The AVR-IoT WG development board is a small and easily expandable demonstration and development platform for IoT solutions， based on the AVR® microcontroller architecture using Wi-Fi® technology. It was designed to demonstrate that the design of a typical IoT application can be simplified by partitioning the problem into three blocks：

　　• Smart - represented by the ATmega4808 microcontroller

　　• Secure - represented by the ATECC608A secure element

　　• Connected - represented by the WINC1510 Wi-Fi controller module

　　The AVR-IoT WG development board features a USB interface chip Nano Embedded Debugger （nEDBG） that provides access to a serial port interface （serial to USB bridge）， a mass storage interface for easy ‘drag and drop’ programming， configuration and full access to the AVR microcontroller UPDI interface for programming and debugging directly from Microchip MPLAB® X IDE and the Atmel® Studio 7.0 IDE. The AVR-IoT WG development board comes preprogrammed and configured for demonstrating connectivity

　　to the Google Cloud IoT Core.

　　开发板AVR-IoT WG 主要特性：

　　• A light sensor

　　• A high-accuracy temperature sensor - MCP9808