GVS-32U4 Revision X2

The GVS-32U4 Revision X2 board is the second generation of GVS-32U4 board based on the previous X1 Revision board. The board includes the features:

• Arduino Leonardo compatible
• Program board using the Arduino IDE  (Download)
• ATMEL ATMega32U4 Processor
• Low-power
• Max. Operating Frequency: 16 MHz
• 8-bit AVR RISC-based microcontroller
• 32KB flash program memory
• 2.5KB SRAM
• 1KB EEPROM
• USB 2.0 full-speed/low speed device
• 12-channel 10-bit A/D-converter
• Pin Count: 44
• Max I/O Pins: 26
• Ext Interrupts: 13
• USB Transceiver: Yes (1)
• USB Speed: Full Speed
• USB-Mini connector
• Standard connection as USB peripheral
• Does not require an FTDI part/connector
• Three flexible power options - Jumper controlled
  
• Power from the USB port
• The USB input is polyfuse protected
  
• Power from External VIN pins (> 6.5V required)
• Uses an on-board Low Dropout (LDO) Voltage Regulator (1.4V min drop)
  
• Embedded power option
  
• Power from reverse powering one of the GVS connector power pins
• Red Power LED
• GVS connectors for all input/output pins
• GVS wiring is compatible with standard servo pinouts on 0.1" pitch
• Note that typical servo connectors are wider than 0.1"
  
• GVS wiring provides the ultimate in flexibility since individual sensors and outputs can be fully connected with standard 3-pin to 3-pin cables
• Pololu is a good source of 0.1" pitch crimp connector housings and wires with pre-crimped terminals
  
• Four solid 4-40 screw mounting holes
• Mounting holes are spaced at 41mm x 41mm
  
• Board size is 49mm x 49mm (less than 2"x2" which is smaller than the Leonardo 2.7" x 2.1")
  
• Rounded board corners for installation into chassis with internal rounded corners such as inexpensive plastic project boxes
  
• HWB jumper for programming part over the USB
• Program using FLIP
• Pullup resistor to VCC
  
• Compatible with Arduino Leonardo bootloader
  

Improvements from GVS-32U4 Rev X1 Board

• Changed signal legends on headers from ATMega32U4 pin names to Arduino [Leonardo] pin names
• Added Serial Number marking area (Mark using Sharpie)
  
• Put all configuration headers in the bottom left corner
• Moved Power header to bottom left corner and labeled more clearly
• Moved Input Voltage header to bottom left and labeled more clearly (EXTernal power and USB power)
  
• Moved Reset header to bottom left and labeled more clearly
• Oriented all headers so that pin 1 is to the outside of the PCB and is wired to Ground
• Rings
• Board rings are Ground on outer ring
• Voltage on center of ring
• Signal on the inner ring
  
• Added GVS silkscreen to all ends
• Added pbworks path to bottom silkscreen
• Increased size of component silkscreens
  
• Made PCB larger (49mmx49mm) for cheaper build by seeedstudio.com fusion service

Further Improvements Needed to the X2 Board

• There are two D6 markings on the board. There should only be one D6. Marking near C5 should be D5.
  
• Add an L-C low pass filter to AVCC (Analog VCC) as described herein:

http://electronics.stackexchange.com/questions/36167/understanding-the-avcc-pin-wiring-on-arduinoleonardo-low-pass-filter/74368#74368

GVS-32U4 Mechanical Dimensions

Port to Pin Mapping

From the Arduino Leonardo page:

• Serial: 0 (RX) and 1 (TX). Used to receive (RX) and transmit (TX) TTL serial data using the ATmega32U4 hardware serial capability. Note that on the Leonardo, the Serial class refers to USB (CDC) communication; for TTL serial on pins 0 and 1, use the Serial1 class.
• TWI: 2 (SDA) and 3 (SCL). Support TWI communication using the Wire library.
• External Interrupts: 2 and 3. These pins can be configured to trigger an interrupt on a low value, a rising or falling edge, or a change in value. See the attachInterrupt() function for details.
• PWM: 3, 5, 6, 9, 10, 11, and 13. Provide 8-bit PWM output with the analogWrite() function.