VOICE RECORDER WITH PIC AND EEPROM

Description

Solid-state voice recorder/player module with features similar to an ISD chip, but made up of a microcontroller and an external EEPROM memory rather than a single chip. The module uses two SMD memories, to which two more DIP chips can easily be added by inserting them into the dedicated sockets. Particularly suitable for security and alarm systems, it works in stand-alone mode but can also be programmed via PC. The SPC01 Speech Module has neither a microphone input nor a speaker output: this choice is because we want to present a module around which everyone can build their own signal amplification chain, designed explicitly for the application they intend to implement. For those of you who have not yet figured out how to use the recorder, but would still like to get an idea of the features and operating modes offered by the module, we have created a “demo” board (7100-SPC-DK) on which you can mount the SPC01 module and start using it. Our demo board offers a microphone input, a line input, a speaker output, and a line output. The DIP switches allow easy setting of the various available functions, including the serial interface. N.B. the board does not include the two 24LC1025 DIP memories.

SPECIFICATIONS

Description of the firmware developed for the microcontroller (a PIC18F2420) that manages the modules, listing the macro-functions it performs:
– Management of the recorder operating logic (button interface, DIP switches, and serial port)
– Management of ADC and PWM peripherals
– ADPCM compression/decompression of acquired audio samples
– Management of an internal 128B RAM buffer for interfacing with the EEPROM memory
– Page-based management logic for EEPROM memories: each memory contains 1024 pages of 128B each, for a total of 128 kB or 1 Mb.

FEATURES

• Recording duration:
  – 65 seconds @ 16 ksps / 130 seconds @ 8 ksps – 4 memories
  – 48 seconds @ 16 ksps / 98 seconds @ 8 ksps – 3 memories
  – 32 seconds @ 16 ksps / 65 seconds @ 8 ksps – 2 memories
• Controls: PLAY / PAUSE, STOP, REC, TRACK SKIP
• Functions: Beep end of track, single track loop, loop over all tracks, sequential or addressed track access, deletion of last track or global deletion, commands and functions via serial port (RS-232), red and green status LEDs.

SOFTWARE “Audio Transfer”

It is used to read the content of the SPC and transfer it to a new SPC. Download software “Audio Transfer”

BLOCK DIAGRAM

DEMO BOARD SPC-DK AND SPC01 MODULE

SPC01 MODULE MOUNTED ON THE SPC-DK DEMO BOARD

ACCESSORIES NOT INCLUDED

The DEMO BOARD code 7100-SPC-DK and the power supply are not included.