Difference between revisions of "Alpha Clock Firmware"

Revision as of 16:19, 24 December 2011

The Alpha Clock Five is an alarm clock and alphanumeric LED display development platform based on the ATmega644A AVR microcontroller. It can be programmed through an AVR ISP programmer, using standard AVR-GCC techniques, or through an FTDI USB-TTL interface, using a modified version of the Arduino development environment.

Bootloader (Arduino style) programming

Alpha Clock Five kits are preprogrammed with the Sanguino Bootloader.

Environment

Alpha Clock Five requires a rather specialized programming environment, that uses some older software versions and will be updated in the near future.

Required software:

• Arduino 0023 (available here), an older version of the Arduino development environment.
• Sanguino version 0023r2.zip from here. (This is an updated version of the Sanguino extensions to Arduino, by Ryan M Sutton.)

Install the Arduino program on your computer. The Sanguino extensions need to be installed separately, and the method for that depend, very slightly, on your operating system:

Installation, Mac

First unzip the Sanguino-0023r2.zip file, which reveals a folder called "Sanguino." Then, find the location where you need to install it.

• Locate your Arduino.app file, version 0023 (which you may have just installed).
• Ctrl-click the file to show the contextual pop-up menu.
• From that menu, select "Show Package Contents."
• Within the resulting directory (Arduino.app), navigate to the folder Contents > Resources > Java > hardware
• Inside "hardware" there several folders, including one called "arduino." Copy the whole "Sanguino" folder, which you unzipped earlier into the hardware folder, next to "arduino."
• Restart Arduino.

If the Sanguino software is installed correctly, you will see Sanguino options in your Tools>Board menu.

Installation, Windows

First unzip the Sanguino-0023r2.zip file, which reveals a folder called "Sanguino." Then, copy that to within your Arduino application.

• Locate your Arduino application
• Copy /Sanguino to arduino-0023/hardware/
• You should end up with arduino-0023/hardware/Sanguino/
• Restart Arduino.

If the Sanguino software is installed correctly, you will see Sanguino options in your Tools>Board menu.

Installation, Linux

First unzip the Sanguino-0023r2.zip file, which reveals a folder called "Sanguino." Then, copy that to within your Arduino application.

• Locate your Arduino application
• Copy ~/Sanguino to arduino-0023/hardware/
• You should end up with arduino-0023/hardware/Sanguino/

• Restart Arduino.

If the Sanguino software is installed correctly, you will see Sanguino options in your Tools>Board menu.

Board type and device signature

When using the modified Arduino environment (the "Sanguino environment"), select "Sanguino W/ ATmega644P" from your Tools>Board menu.

Technical note: the device signature that the Alpha Clock's bootloader returns is that of the ATmega644P (not the ATmega644A). (This is intentional. It is (1) code compatible and (2) better supported under both AVR-GCC and the Arduino/Sanguino environments. There are longstanding bugs in the support for the 644A, and this is a stable and sane workaround.) The "hardware" device signatures-- those that you will read if you try to reprogram the AVR through an ISP interface --do remain those of the ATmega644A.

Uploading firmware

Connect your FTDI interface (e.g., USB-TTL cable) to location J2 on the circuit board (the 6-pin SIL right-angle header also labeled "LOGIC-LEVEL (TTL) SERIAL"), watching the polarity. For one of the cables with rainbow-wires on the end, black goes down, green goes up.

Make sure that the correct serial port is selected in the Tools>Serial Port menu.

Make sure that the correct board type is selected in the Tools>Board menu.

Make sure that Alpha Clock Five is powered on.

Click the "Upload" button in your Arduino window to upload the sketch.

Programming the bootloader

Most users will not need to reprogram the bootloader at any point.

Programming the bootloader onto a new ATmega644A requires an AVR ISP programmer (see more about that below). This can be done directly from within the Arduino environment (using the Tools>Burn bootloader option), but is complicated by the fact that we are using an ATmega644A rather than the ATmega644P normally expected by Sanguino.

First, download and install this alternate version (130 kB .zip file) of the Sanguino software, which includes a definition of the 644A for purposes of using the bootloader.

Then, to install the bootloader:

• Select as your board type (from Tools>Board), "Sanguino W/ ATmega644/644A"
• From Tools>Burn Bootloader, select your AVR ISP programmer type, to actually burn the bootloader

After installing the bootloader, select board type "Sanguino W/ ATmega644P" when you wish to reprogram the board through the bootloader, as the "software" device signatures returned by the bootloader are those for the '644P. If you reprogram the board through an ISP programmer (including reburning of the bootloader), you will still need to select ATmega644A as the device type.

AVR ISP Programming

The Alpha Clock Five PCB features a 6-pin AVR ISP connector (J4), which can be used to program the microcontroller through any suitable AVR ISP programmer. We recommend the Adafruit USBtinyISP programmer for most purposes. The Alpha Clock Five should be powered separately from 5 V while programming; Alpha Clock Five requires more power than can usually be safely provided by USB.

The circuit can be programmed through AVR-GCC or any other AVR software environment, including AVR Studio. If using AVR-GCC, you may find it helpful to target (set the MCU type as) the ATmega644P rather than the ATmega644A, as it is better supported.

Please refer to the schematics (PDF) for pinouts and electrical features of the Alpha Clock Five.

Standard Firmware