Saturday, 25 January 2014
I was in Tesco today and saw a DAB alarm/clock/radio for £5. Five pounds. Well, that's got to be worth a poke - even if it lasts 10 minutes before I've blown it up it'll be good value.
Inside there are three boards. The smallest board takes 5V in and offers a headphone out via an 8-pin TSOP amplifier. The largest board runs the MMI and houses the screen and all of the buttons. That's connected via a 14-pin ribbon to the main event - a Gyro-1130E DAB module from GyroSignal Technology Co Ltd.
This FM/DAB module drives the single speaker directly, sends a 5 pin (differential) stereo audio to the headphone amplifier and carries a ton of plated through holes along each of, 14 of which go the MMI board as I mentioned before. The interesting bits are mostly hidden under a large can labelled 'Tunbow', but you can see an FC2507 (PDF) tri-band downmixer from Future Communications Integrated circuit Inc. I might try and lift the can at some point, but there's a whole lot of solder holding it down.
The "Tunbow" label on the can was odd, so I looked it up. It turns out, they make DAB radios and in fact make a radio in an identical case - the a Tunbow E80012. The only difference is in the picture, that has a segmented LCD, whereas mine has a dot matrix (which is actually as described in the specification, so perhaps the picture is just wrong).
Anyway, the audio quality isn't bad and I've seen references to a Gyro-1128 module receive praise in a full-size Audiolab 8200-T DAB receiver. This is quite promising. If I see another, I'll buy it so I can destructively lift the can and see what's underneath.
Monday, 20 January 2014
Wednesday, 15 January 2014
I've elected to stay with 8-bit mode as I need the pins as GPIO. Text rendering works well provided you are careful to over print a region rather than blanking it first (which causes a flicker).
The fonts came from UTFT. I might patch them to add proportional support but monospace is fine for now. I've knocked up a basic menu system too.
Tired of all the wires the prototype, I ordered some PCBs from OSHpark.com. $50 for three, they should be here any day now.