"MatrixType" 2-pin header
A few words about the "MatrixType" 2-pin header, found between the EEPROM and PORT_C header. With the jumper on, pin D11/PD3 is pulled down (that is, connected to the ground). When the jumper is not present, pin D11/PD3 is pulled up by the 10K resistor. By reading the state of this pins, the sketch can adapt to display on either the 16x24 or the 8x32 LED matrix display from Sure Electronics. The software support is almost trivial. The hardware is not. Plugging the active (SV1) connector directly into the 8x32 LED display makes for an awkward beast (since the dimensions of the 2 boards are so different). But it can work with a 16-wire ribbon cable.
Note: As of today, the software support for the "MatrixType" is not yet tested.
ICSP6 6-pin header
This is the standard connector used for programming the microcontroller chip with the AVR programmer. As in Arduino Diecimila, one rarely needs to use it for burning a program, since the bootloader (already burned on the chip) allows for easy upload of a sketch from the IDE.
6-pin inline, right-angled header
This header is used for connecting with the FTDI cable, or with the equivalent FTDI basic breakout from Sparkfun. This is the only way to upload a sketch from Arduino IDE to the Duino644 board. Keep in mind that the USB miniB connector is only used to provide power (5V), unlike the USB connector on most of the Arduino-type boards (which have the FTDI chip on board).
The next batch of PCBs will include a few corrections in the silkscreen: the 16MHz crystal is marked "XTAL" and the places for DS1307 and 24LC256 are clearly marked. Also, the 3 buttons are visibly named on the back of the board, useful if the enclosure has a transparent back panel.
As mentioned in an earlier post, the USB power connector can be either miniB or B type. If you have a preference for either one when you buy the kit, please let me know and I will accommodate it.
Next post will be about software. A quick "to do" list includes:
- functionality for the 3 buttons (menu, scrolling speed, dimming, set clock/alarm etc);
- IR functions for remote control;
- extend time displayed to include year/month/day;
- include the alarm/melody functions (plus 2 sound-intensities through the speaker);
- sleep (power down) mode;
- alarm functionality (set/sound/trigger/enable/disable);
- support for "matrix type".
Edit: As of Jan/10, all (except the last) of the above "to do" items have been implemented and are currently implemented in the latest software release.