ISD1820
Overview
This module board is based on ISD18B20, which is a single-chip single-message record/playback device. Recordings are stored into on-chip non-volatile memory, providing zero-power message storage.
- Power input: DC 2.4-5.5V
- With internal audio amplifier, this board can drive 8 Ohm 0.5W speaker directly.
- Microphone is on board
- Board dimension: 54mm x 38mm
- All the pins of ISD1820 are extended out with an connector, which can powered and controlled by microprocessor directly
- Functions The following is the board picture. The following is the schematic. There are 3 keys on the board: REC, PLAYE and PLAYL 1) REC The REC input is an active-HIGH record signal. The device records whenever REC is HIGH. This pin must remain HIGH for the duration of the recording. REC takes precedence over either playback (PLAYL or PLAYE) signal. If REC is pulled HIGH during a playback cycle, the playback immediately ceases and recording begins. A record cycle is completed when REC is pulled LOW. An End-of-Message (EOM) marker is internally recorded, enabling a subsequent playback cycle to terminate appropriately. The device automatically powers down to standby mode when REC goes LOW. This pin has an internal pull-down device. Holding this pin HIGH will increase standby current consumption. 2) PLAY There are two modes to play the voice in the voice chip: edge activated mode controlled by PLAYE pin and level activated mode controlled by PLAYL pin. (1) Playback, Edge-activated: When a HIGH-going transition is detected on this input pin, a playback cycle begins. Playback continues until an End-of-Message (EOM) marker is encountered or the end of the memory space is reached. Upon completion of the playback
