hi am sudam bhagwat i want the c code for interfacing R305 with PIC18F4520

The fingerprint sensor is combination of R305 FP+PIC MCU board that can read different fingerprints and store in its own flash memory. The sensor can perform three functions namely Add(Enroll) , Empty Database or Search Database and return the ID of stored fingerprint.

Any of three functions can be called simply by making the pin low of the sensor or pressing onboard three switches. The response is either error or ok which is indicated by onboard LED. The response is also returned as single serial data byte. The return byte is a valid ID or error code. The response byte is a single byte at 9600 bps thus making whole sensor very easy to use. We have provided indicating LEDs and function switch already so it’s ready to use when you receive it. Just give power and start using the sensor using onboard switches. Then you can move on making external application using these functions.

Features

Easy to use
Status LEDs
Function Switches
Single byte response
Works at 5V
UART 9600bps response
Inputs and Outputs of Sensor

Input: Two ways to trigger the function of fingerprint sensor

Onboard switch: Add, Empty or Search.
Make pin low from external microcontroller for 5ms as per function required to be executed.
Outputs(Response): Two ways to monitor output response after a function is executed

Onboard LEDs: ERROR or OK
Read byte after executing function
Types of function

There are namely three functions you can call for the fingerprint sensor. We will see each in brief.

Add(Enroll) Function: Adds a fingerprint to database and return a byte of newly added ID. Return values are from 0x00 to 0xFE. In case of error like no finger placed, return code is 0xFF. Here 0xFF means error executing function

Search Function: When a finger is put and search funtion is called, it returns a matching ID if found in its existing memory. Return values are from 0x00 to 0xFE. In case of error like no finger placed, return code is 0xFF. Here 0xFF means error executing function.

Empty Function: When you wish to empty all fingerprint data stored on sensor you can use this function. After executing this function, you will get 0xCC as OK or 0xFF in case of error.

Application Example

We will use an example of AT89S52 MCU to interface but can be any MCU like AT89C51 or AVR or PIC. Since the sample code is in C language. The logic will remain same across all C compilers.