Understanding FM Broadcast Receiver with RDA5807FP

Question

I've been trying to build an FM broadcast receiver for the last few weeks know, with simple designs like with LC circuits, but I've realized that an IC based radio outperforms simple transistor radios. I've started looking a round for cheap FM receiver chips, and I've found one that is used in many soldering kits, called the RDA5807FP. I found a schematic online for the soldering kit, as pictured below.

I also looked at the datasheet, and it seems like it wouldn't work in the above configuration. By default, the chip is muted, and it seems like there is no way to change that, besides with I2C. I2C is volatile (I believe), so if they programmed it once with I2C and turned it off, everything would reset, and the chip would be muted again, leaving us with the same problem as before. The only way the datasheet says that it can interface is this: "Only support 2-wire bus interface", so (I believe) it is referring to the earlier-mentioned I2C. Even the example circuit in the datasheet is configured to work with I2C:

So, my question is, how does this simple FM receiver work without a microcontroller? Is there something in the datasheet that I'm missing?

I'm also open to suggestions about different chips, along as it's simple, cheap, and still produced.

Thanks for all your help, and I apologize for my beginners ignorance.

Answer 1

I think the RDA5870FP is a programmable FM Radio chip can be controlled in a simple way with push buttons when pin6 is held High. Then the GPIO pins 1,7,8,15,16 are then: power, ch-, ch+, vol-, vol+ and there is a datasheet, RDA7088, which refers to this configuration. When pin 6 is held lo, then it can be controlled by i2c with rds and i2s output, which is shown in the RDA5870FP datasheet.

Answer 2

**Danger! This circuit with the RDA5807FP (**HEX3653); has SEVERAL PROBLEMS:

1. THE CIRCUIT WITH THE NPN TRANSISTOR DESTROYS THE IC! THIS POWER ON OFF function MUST NOT BE USED IN THIS WAY!! BECAUSE THIS CONFIGURATION WILL DESTROY THE IC!! BECAUSE DURING POWER ON, THERE IS A VOLTAGE OF 0.88 V ON THE AUDIO PINS 12 AND 13, WHICH REVERSES THIS VOLTAGE AS A NEGATIVE VOLTAGE WHEN THE IC IS TURNED OFF BY THE TRANSISTOR! THE CMOS IC CAN’T TOLERATE THIS! THIS CIRCUIT MUST BE OMITTED!! THIS IS MANDATORY! FURTHERMORE, THE CIRCUIT AT THE ANTENNA INPUT HAS AN INPUT LEVEL MUCH TOO SMALL FOR THE IF!! THE RESULT IS A POOR RECEPTION!! THE LEVEL HERE IS JUST PRESET AT 0.3 dbm! THE LIMITER DIODES ARE MANDATORY! SO NOTHING LEFT FOR FM STATION RECEPTION!!! THIS MEANS THAT HERE THE IF IS PRACTICALLY SLOWED OUT TO THE EXTENT THAT RECEPTION IS REALLY NOT POSSIBLE! THERE IS NO REMEDY!! IT MAY HELPS AN UNREALLY LONG WIRE WITH AT LEAST 1 METER, BUT THIS IS NOT AN OPTION IF YOU WANT TO INSTALL THE RADIO KIT INTO A CASE OR RADIO! A telescopic antenna is practically WITHOUT sufficient reception power! Therefore: The RDA5807 FP (**HEX3653) is NOT REALLY USABLE!! CONCLUSION: THE POWER ON OFF FUNCTION, CONTROLLED VIA THE NPN TRANSISTOR FROM THE AUDIO OUT PIN IS POINTLESS!! BECAUSE THAT WILL DESTROY THIS IC!!! UNFORTUNATELY!! The resistors included in the kit MUST be used AFTER the decoupling electrolytic capacitors!!! THIS IS ALSO MANDATORY!!
2. THE FM RECEPTION of these two ICs IS UNUSABLE WITHOUT AN APPROPRIATE ANTENNA LENGTH OF AT LEAST 1 METER!! ANOTHER NOTE ABOUT THE CIRCUIT REGARDING THE I²C BUS: THE CONTROL USED HERE WITH BUTTONS FOR TUNING ON THE SDIO AND SCLK IS FUNCTIONAL, BUT THERE IS NO INFORMATION ABOUT IT IN THE MANUFACTURER DATASHEED! I found this circuit interesting at first, but I quickly had to experience the aforementioned for myself! AND IF THE PIN 6 HERE HAS TO BE SWITCHED TO VDD INSTEAD OF GND, THAT CAN ONLY BE A SPECIALLY PROGRAMMED GPIO THAT SWITCHES THE I²C BUS ON OR OFF HERE!! BECAUSE, AS MENTIONED, THERE IS NO DOCUMENTATION IN THE DATA SHEEDS!! THE SAME THING DESCRIBED HERE ALSO APPLIES TO THE HEX3653 FM RADIO IC - IN THE DIY KIT WITH THIS IC WHICH IS PIN COMPATIBLE AND FUNCTIONAL SAME TO THE CIRCUIT VERSION HERE OF THE RDA5807FP (*HEX3653 ALSO!)!! AS PROOF: I HAVE SET UP THIS RADIO KIT 10X AND THE FINDINGS ABOVE LEAD TO IT DESTRUCTION!! I was at least able to “save” 3 kits after the kits that were first manufactured!!(SEE POWER ON/OFF FUNCTION) ON THE AUDIO PINS! So: STAY AWAY FROM THIS FAKE CIRCUIT!! IT DOES NOT WORK ERROR-FREE AND WILL DESTROY THESE ICs!!!

Answer 3

So is a BIG PROBLEM for this Circuits with RDA7088, GS1299, HEX3653 AND RDA5807FP!!! THE PROBLEM No 1 is the FATAL ERROR, when you CONNECT THE SWITCH ON PIN 1, AND PINS 7+8, and PIN 16!!! THIS FUNCTIONS DEMAGED THIS IC's!!!!! AND PROBLEM No 2 is THIS: In the KIT-CIRCUITS ARE A FATAL ERROR: THE TRANSISTOR ON THE AUDIO-OUTPUT-PIN FOR POWER-ON-LED IS A FATAL ERROR: THIS CONFIGURATION DEMAGED THIS CMOS-IC's; ON THIS AUDIO-OUTPUT-PINS leaks A VOLTAGE OVER 0,88 VOLTS!!! THIS IS NOT GOOD, WELL THIS VOLTAGE DEMAGED THE INTERNAL CMOS-AUDIO-DRIVES, AND THE AUDIO-LEVEL FOLLOWS WITH ON/OFF-BULKS ON POWER OFF/STANDBY!! THESE SPIKES IS ALLREADY HEAR ON THE EXTERN SPEAKERS/EARPHONES!!! SO DEMAGED THE AUDIO-OUTPUT-DRIVES!! FOLLOWED: WHEN IC GOES STANDBY-MODE WITH THIS POWER-ON/OFF-FUNCTION, THE AUDIO-OUTPUTS ARE NEVER MUTET!!! SO IS THE IC WITH FULL ERROR-FUNCTIONS EVER ON!! NOT IN FUTURE ONLY, BECAUSE ONLY EVER NOT IN STANDBY!!

THIS (*DIY, SPARFUN AND OTHER !!!)-KIT-CONFIGURATIONS WITH THIS CIRCUITS ARE ALL A FAKE !!! WELL THIS CONFIGURATIONS DEMAGED THIS IC's!!! CAUTION!!! THIS INFOS HAS BUILDING ALL ON MY PERSONALY PRACTICES!!! YOU CAN SELF TESTING: THE POWER ON/OFF ON PIN 1, IS FATAL ERROR!!! PLEASE RE-CONNECTING THIS FUNCTION AND NC PIN 1!!! AND PIN 7, 8 IS ALSO ONLY FOR I²C-BUS WITH EXTERNAL MPU-CONTROLLERS ONLY!!!NOT SWITCHES FOR SCAN TUNING!!!! AND THE SWITCHES ON PI 15+16 ARE EVER NOT CONNECTED!!NC!!!! THIS PIN'S ARE ALL FREE!!!! SO; AND THE PIN 6 IS ONLY FOR GND!!! NOT VDD CONNECTED!!!! THIS FUNCTION DEMAGED THE IC!!!!!! AND: IN KIT-CIRCUITS WITH THE POWER ON-LED DRIVE TRANSISTOR ON THE AUDIO-OUTPUT PIN 15, AND/OR PIN 14,ARE ALLREADY NOT CONNECTING!!! THIS PIN'S ARE ONLY FOR AUDIO-OUT!!! AND NOT FOR POWER-ON/OFF-FUNCTION!!!

THIS COMMENTS ARE ALL FROM MY PRIVACY TECHNICAL PERSONALY SERVICES!! YOU MUST ARE ALL CHANGES THIS DOCUMENTARED ERRORS AND CONNECTINGS ON PINS, IN THIS PRODUCT - CIRCUITS FOR RDA5807FP, HEX3653, GS1299 AND RDA 7088 (* AND OTHER IC's?!!); AND DIVERSE PRODUCT IDEAS!! YOU MUST THIS COMMENTS ACCEPT IT!!! IS ONLY FOR YOUR PERSONALY PROJECTS! ONLY SO YOU HAVE IN FUTURE MORE FUN FOR YOUR RADIO-CONFIGURATIONS!!! PLEASE LIKE NOT THIS COMMENT!! I HAVE NOT FOLLOWER-ACCOUNTS!! I AM ONLY PRIVACY AND HAVE NOT ONLINE BULLSHIT REGISTRATIONS!! THIS IS ONLY FOR ....!! NOT FOR OR WTH ME!!!

Also: THE PRIVACY DATA, NAME, EMAILADRESS AND OTHER DATA ARE ALL N O T FOR INTERNET!!! THIS ARE ALL ONLY MY PRIVACY AND N O T FOR INTERNET! PLEASE ACCEPT IT!!

THE NAME AND EMAIL-ADRESS IS PROVISIONING ANONYMUS!! SO, I HAVE NO PROBLEMS WITH CRIMINALNY PERSONS ON INTERNET!!!