There certainly are 6 lines available. bits 0 and 1 are used up when the serial interface (even just the USB) is enabled. But the rest of the low 8 buts is uncommitted. So you send the data as a pair of nybbles?
Could you perhaps post a bit of info to help me and others. Suggest a display model that works in that mode (would need to be operable in a graphic mode) and if d2 - d7 would be appropriate to use. If you have a circuit sketched that would be great. My only experience with LCDs has been ready-to-go kits, and programming the RS-232 interfaced ones.
Jerry did point out that the A/D lines can be used as digital. But the concern is introducing switching noise when reading adjacent pins as analog.
JIm, you might like to look at this project (kit) which sells for about $100 all up with display for inspiration. It can be bought with PC interface only for half that or add the seperate display driven serially. Or, a bluetooth pcb that displays on an Android phone. Schematics are available on the page also.
[having trouble posting it seems]
--- In PHSNA@..., <phsna@...> wrote:
I've been puzzling over how to configure the SSNA so at least it doesn't **prevent** the addition of a display. Better Arduino heads than mine may be needed for advice and counsel here.
I'm going under the presumption that the UNO has 14 digital I/O lines available. The DDS interface uses 4 (D8 - D11 at this time, but that can change).
Most LCD displays (parallel interface) need 8 data lines, an enable, a read/write line, and a clock. That adds up to 15. That may preclude the addition of a parallel display on the UNO. Of course a (more costly) serial LCD would solve that problem. And the serial TX and RX lines are not used by the SSNA.