PROGRAMMING AN FM-AM RADIO TUNER USING THE LC72131 PLL IC Radio receivers made with LC72131 IC, and other members of this family, were frequently used in many Music systems, portable Radio - Cassette Players etc. devices in the 90s and 2000s. Thanks to the PLL frequency adjustment technique created using these ICs, it has been possible to make radio receivers that work stably. In this post, I will try to show how to tune an FM-AM receiver from such an old music system to the desired frequency (or station, as it can also be called). PURPOSE Tuning any FM-AM radio receiver using LC72131 IC, a member of the LC72xxx series PLL IC (integrated circuit) family produced by Sanyo, to the desired frequencies. WHAT IS REQUIRED A receiver circuit (Tuner stage) using LC72131 PLL IC. Audio frequency amplifier to connect the receiver circuit to the audio output. AT89S52 Microcontroller. Text editor required to program the microcontroller in Assembly language (Ex: Notepad ++) Asm51.exe .ASM to .HEX co...