NS73M FM Stereo Xmtr - Data Retention

Wireless & IoT
1

Does the NS73M hold it’s settings or does it have to be reprogrammed each time power is applied?

2

I assume the data sheet would have the answer.

But without even looking at it, I strongly suspect that it must be reconfigured each time it is powered up.

Including non-volatile memory would significantly increase the manufacturing cost of the chip.

Pete

3

Thanks Pete.

I’ve read the data sheet and it doesn’t seem to address the issue – so by default I would suspect the device doesn’t retain data – particularly since it is CMOS. If it did retain data I suspect it would be in big letters at the top of the data sheet with all of the other marketing hype.

I plan to hang a PIC onto it anyway so it’s just a slightly more complicated program. I use Source Boost C and they have great support for the I2C bus both in bit bang mode and in hardware mode where the chip supports it (16F877 et al).

Cheers

4

Just saw this thread and wanted to let you guys know that you’re right; the NS73M does not retain data when it’s turned off.

5

Thanks for your comments. I have it working with a little 8 pin 12F683 PIC and it looks great on the spectrum analyzer. The PIC takes care of frequency storage and loading.

6

Hi Rye,

How is the sound quality? Have you seen the Silicon labs Si473x chips?

Grego

7

punkied:
Hi Rye,

How is the sound quality? Have you seen the Silicon labs Si473x chips?

Grego

I can now say: it’s quite good!

Hiss is very low, and you’d only hear it on very low audio anyway. Dynamic range is good.

I took Cai Maver’s code and collaborated a bit with him. He built some IC setup code for Arduino. Later he switched the communication to 2-wire (Arduino Wire.h protocol). I added an LCD (4-bit interface) and some code for handling frequency changes, taking it on and off air, and saving the frequency to EEPROM so it’ll be reloaded the next time it powers on.

I’m attempting to document that project here:

http://www.mikeyancey.com/FM-Stereo-Broadcaster.php

Arduino is a fun platform and the NS73M works very well.

Mike Yancey

Dallas, Texas

8

Thanks for the update! I have ordered the chips, and have to get busy hooking them up :slight_smile:

Grego