MHVBoard

The MHVBoard is a low cost Arduino clone, based off the Metaboard.

It offers a TTL serial port, USB programming, ICSP, breadboard compatible headers and hardware already set up for software USB via V-USB.

While the original Metaboard did not choose to issue a license, our revisions are licensed under TAPR Noncommercial Hardware License.

Getting one

You can pre-order an MHVBoard R7 from the MHVBoard Pozible project page.

Features

Supports native USB direct to the microcontroller via V-USB
TTL level serial port
Programming via USB
Onboard prototyping area for additional hardware
Shield compatible - Revision 4+ only
Plugs into double-width breadboards (Revision 1-3), and single width breadboards (Revision 4+)
Atmega328P microcontroller with 30kB flash, 2kB RAM, 1023Bytes EEPROM available
ICSP header to update the bootloader
All through-hole construction (except for a voltage regulator with large easy to solder legs) for easy hand assembly
Supports Arduino and Flame runtimes, as well as raw AVR-GCC
20MHz clock - your code runs faster than the Arduino boards
Pins labelled both with Arduino pin numbers and port/pin numbers
Automatic detection of power source - USB or external power
4 mounting holes for extra stability
AREF decoupled for improved ADC accuracy
Onboard LED can be disabled to reduce loading on the line
Up to 1A can be drawn from the 3.3V line, and 1.5A from the 5V line (when using an external power supply)

Differences to the Arduino series

Native USB interface for uploading (USBasp), no serial ports involved
Serial port brought out on a TTL Header
Arduino pins 2 and 4 are used for USB communication. If you connect additional hardware to these pins, your program should not use the USB port. This hardware should also be disconnected before connecting to your computer
Arduino pins 0 and 1 are normally used for the Serial port, if your program does not use the Serial port (since USB is available), these pins are available for use
Breadboard compatible pin headers (no shields) - Revision 1-3
Arduino shield and breadboard compatible headers - Revision 4+
20MHz clock vs 16MHz on the Arduino
Due to the additional filtering on AREF, it takes time for AREF to stabilize after a different reference voltage has been selected. The first reading after the reference has changed should be discarded.
3.3V current up to 1A (vs 50mA), and 5V current up to 1.5A (with a suitable heatsink on the 7805 regulator)

Instructions

Credits

Big thanks go out to the many open-source and commercial projects that made this project happen.

Metalabs MetaBoard - the starting point for our board
Cadsoft Eagle - the free for noncommerical use PCB program used to create our board
GCC - the Gnu C Compiler
Objective Development’s V-USB & USBAspLoader - the software USB library and bootloader we recommend
Sparkfun - for providing the DC jack & mini USB footprints

Download

The latest version can be obtained from our Git Repository:

git clone https://github.com/InfernoEmbedded/mhvboard.git

R2 Assembly Instructions

MHVBoard R2 Assembly Instructions Tools You will need the following tools to assemble your MHVBoard: Soldering iron with a fine tip (25W will do) Solder (the PCB is ROHS compliant if you want to use lead-free solder, but lead based solder is easier to work with) Needle-nose pliers Side cutters Multimeter Blu-tack PCB Carefully inspect both sides of your PCB for solder dags and scratches. If there are scratches on your board, use a multimeter set to continuity and refer to the board layout to ensure that no traces have been damaged. ...

Useful Information

JP4 pinout The right angle connector has the following pinout (starting from the pin near JP1): JP4 Pin Arduino Shield Pin Description 1 0 D0, Serial RX, PCINT16 2 1 D1, Serial TX, PCINT17 3 2 D2, INT0, PCINT18 4 3, PWM D3, OC2B, INT1, PCINT19 5 4 D4, XCK, T0, PCINT20 6 5 D5, OC0B, T1, PCINT21 7 6, PWM D6, OC0A, AIN0, PCINT22 8 7 D7, AIN1, PCINT23 9 8 B0, CLKO, ICP1, PCINT0 10 9, PWM B1, OC1A, PCINT1 11 10, PWM B2, SPI Slave Select, OC1B, PCINT2 12 11, PWM B3, SPI MOSI, OC2A, PCINT3 13 12 B4, SPI MISO, PCINT4 14 13 B5, SPI SCK, PCINT5 15 Ground Ground 16 Aref AREF, coupled via 100uH inductor and 100nF capactor 17 Analog 0 C0, ADC0, PCINT8 18 Analog 1 C1, ADC1, PCINT9 19 Analog 2 C2, ADC2, PCINT10 20 Analog 3 C3, ADC3, PCINT11 21 Analog 4 C4, ADC4, SDA, PCINT12 22 Analog 5 C5, ADC5, SCL, PCINT13 23 Vin Vin (from the DC jack) 24 +5V +5V 25 Reset Reset (active low), C6, PCINT14 Solder Jumpers On the underside of the board are a number of solder jumpers. ...

Troubleshooting

Here are some common problems you might encounter when using your MHVBoard. The MHVboard R2 does not appear as a USB device for uploading. Connect the MHVboard to your computer with a USB cable. Make sure the upload jumper is installed on JP6, set the power jumper (JP5) to USB by placing the jumper over the pins 1 and 2 (pin 1 is near the resistors), then press the reset button. LED1 on Pin13 (placed between the USB connector and the power regulator) should blink three times and then turn off) and the MHVboard should be placed in programming mode and your computer should acknowledge that the USB device has been connected. ...

Getting Started in the Arduino Environment

Getting Started with the MHVBoard in the Arduino Environment The MHVBoard will work within the Arduino environment. Install the Arduino Environment version 1.0 Download the MHVBoard enhancements at the bottom of this page and extract it over the top of your Arduino installation If you are running Windows, you will need to download the USBasp drivers, available from the author of USBasp. Linux & Mac machines do not need additional drivers. If you are running a 64 bit version of Windows, you will need to sign the drivers before installation: Download Driver Signature Enforcement Overrider Extract the USBasp drivers Run Driver Signature Enforcement Overrider as Administrator Put your computer into Test Mode (this allows self-signed drivers to run) Sign all the DLL and SYS files in the extracted USBasp driver package Optionally, remove the watermarks from your system (Test Mode will show “test mode” in the bottom right of your desktop) (R2 boards only) Connect the “Upload” jumper on the MHVBoard, move the power jumper to “USB” and connect it to your computer Press the reset button on the MHVBoard to put it into Upload mode. The LED will flicker briefly to indicate that it has entered the bootloader If you are running Windows, the first time you do this, a new device will be detected. Point the driver installer at the drivers you extracted/signed earlier. Launch the Arduino Environment Write/load your sketch Choose “MHVBoard” from the Boards menu Upload your sketch, your sketch will run automatically after uploading To re-enter the bootloader press reset again. As before, the LED will flicker to show it is ready for another upload ...

R7 Assembly Instructions

Tools You will need the following tools to assemble your MHVBoard: Soldering iron with a fine tip (25W will do) Solder (the PCB is ROHS compliant if you want to use lead-free solder, but lead based solder is easier to work with) Needle-nose pliers Side cutters Multimeter Blutac Packing List MHVBoard R7 Packing ListItem Quantity Location 10uF electrolytic capacitor 2 C1, C2 22pF ceramic capacitor 2 C3, C4 100nF ceramic capacitor 2 C5, C6 10uF tantalum capacitor 1 C7 3.6V zener diode 2 D1, D2 1N4001 silicon rectifier diode 1 D3 1N5817 Schottky diode 1 JP5 (not on silkscreen) 28 pin narrow DIP IC socket 1 IC1 Atmega328P 1 IC1 7805 5V voltage regulator 1 IC2 AMS1117 3.3V voltage regulator 1 IC3 1x8 female pin header 2 JP1, JP2 1x6 female pin header 2 JP3, JP8 1x4 pin header 1 JP7 2x3 pin header 1 ICSP (JP9) 1x25 right angle pin header 1 JP4 10uH axial inductor 1 L1 20MHz HC49/S crystal 1 Q1 68Ohm resistor 2 R1, R2 1MOhm resistor 1 R3 1.5KOhm resistor 1 R4 1k resistor 2 R5, R6 3mm LED (random colours) 2 LED1, LED2 6x6mm pushbutton switch 1 S1 5 pin microUSB connector 1 X1 2.1mm DC jack 1 J1 micro USB cable 1 MHVBoard R7 PCB 1 Once you have confirmed that you have all the components, you are ready to begin construction. ...

mhvboard 7

Remove upload jumper Reroute traces away from the crystal Fix silkscreen for Arduino analog input Downloads USBaspLoader.2010-07-27-mhvboard.zip (175.1 KB) MHVBoardR7.7z (187.3 KB)

Getting one#

Features#

Differences to the Arduino series#

Instructions#

Credits#

Download#