Evolved Microcontroller Application Board

Introduction

EMAB will be a microcontroller development board based on an Atmel AVR XMEGA processor. It will include USB-based communication, USB or external DC power, and I/O connectors for extension boards.

Components

Processor

AVR XMEGA A4U series, 44 TQFP package.

USB Interface

FTDI FT230X serial bridge for communication with application code and programming through serial bootloader.

Extension Connectors

Extension slots contain a 16-pin IO connector and 6-pin power connector. Standard form factor EMAB will have two slots, micro-EMAB will have one. Extender boards will connect to either one or two slots (two-slot boards not compatible with micro).

Slots A and B will both include 6 PWM outputs, 1 I2C, 1 UART, 4 ADC inputs. Slot A will have an additional UART and SPI. Slot B will have 2 additional ADC/DAC pins.

A third connector (for direct cable connection, not extension boards) will include additional signals and duplicates of some from A or B.

Pinouts

Main extension connectors

Pin	A	Alternate	B	Alternate
1	GND		GND
2	3.3V		3.3V
3	A0	ADC	A4	ADC
4	A1	ADC	A5	ADC
5	A2	ADC, Async	B2	ADC, DAC, Async
6	A3	ADC	B3	ADC, DAC
7	C0	PWM, SDA	E0	PWM, SDA
8	C1	PWM, SCL	E1	PWM, SCL
9	C2	PWM, RX	E2	PWM, RX
10	C3	PWM, TX	E3	PWM, TX
11	C4	PWM, SS	D0	PWM
12	C5	PWM, MOSI	D1	PWM
13	C6	RX, MISO	A6	ADC
14	C7	TX, SCK	A7	ADC
15	GND		GND
16	GND		GND

UEXT

1	3.3V
2	GND
3	C3	TX
4	C2	RX
5	C1	SCL
6	C0	SDA
7	C6	MISO
8	C5	MOSI
9	C7	SCK
10	C4	SS

Analog input

XMEGA A/D converters require a reference voltage up to Vcc-0.6V. Reference voltage onboard will be switchable between a low-current LDO and precision shunt reference (up to 2.5V). Analog reference signal will be available on extension power connector to be used (or supplied) by extension boards.

Family Planning

Planned board family members:

Size Name	Dimensions (inch)	MCU Package	Usable MCU Parts	USB	Power	Extension Slots	UEXT Headers	Analog reference
Standard/Full	3.4x1.8	44-TQFP	A4(U), C4, D4	FT230X	USB/DC jack, LDO	2	1	2.5V LDO, 2.048V shunt
Micro	2.1x1.8	44-TQFP	A4(U), C4, D4	FT230X	USB/DC jack, LDO	1	1	2.5V LDO, 2.048V shunt
Extra	3.1x2.5	64-TQFP	A3(U)	FT230X, XMEGA?	USB/DC jack, SMPS	3	2	2.5V LDO, 2.048V shunt
Nano	1.8x1.2	32-TQFP	E5	None	Header, LDO	1	1	2.5V LDO

-- StephenCavilia - 28 May 2014