ISD 1700 series chips are single-chip high-quality voice recording and playback circuits introduced by Winbond. The chip provides many new functions, including multi-information management system with built-in patents, vAlert and dual operation mode (independent &; Embedded), and can customize the sound effect of information operation instructions. The chip includes automatic gain control, microphone preamplifier, speaker driving circuit, oscillator and memory.
5.2. 1 Features
It can be recorded and played 100000 times, and the stored contents can be saved without power supply100 years. Two control modes, two recording input modes and two playback output modes can handle more than 255 messages, and the working status prompts are rich and varied. Various sampling frequencies correspond to various recording and playback times, with good sound quality, wide voltage range, flexible application and low price.
electrical specification
Working voltage: 2.4V-5.5V, maximum not exceeding 6V, static current: 0.5- 1 μA, working current: 20mA,
Users can customize the sampling frequency of the chip by using the oscillating resistor, thus determining the recording and playback time of the chip.
5.2.3 Independent key working mode
ISD 1760' s independent key working mode recording and playback circuit is very simple and powerful. It not only has the functions of recording and playing, but also has the functions of fast forward, erasing, volume control, direct playback and reset. These functions can only be completed by pressing keys.
(1) record operation
Press the record key to start recording the sound of the segment corresponding to the current segment number.
(2) Playback operation
Press this key to play the voice corresponding to the current segment number. If you press this key during voice playback, you can stop playback.
(3) Clear key
Press this key to clear the voice corresponding to the current segment number. If you press and hold this key for 2 seconds, all sounds in the memory except the prompt sound will be cleared.
(4) Volume adjustment key
Press and hold this key, the volume will automatically increase and decrease, and then increase again after reaching the minimum.
(5) Next key
After pressing this key, the segment number will be automatically added with 1 to play the next voice. If you hold down this key, 1 will be automatically added to the segment number continuously until the key is released. When the current paragraph number is the largest, pressing this key again is invalid.
The main single chip microcomputer mainly communicates with ISD 1760 through four-wire (SCLK, MOSI, MISO, /SS)SPI protocol. As a slave, ISD 1760 can complete almost all operations through this SPI protocol. In order to be compatible with the independent key mode, some SPI commands, such as PLAY, REC, ERASE, FWD, RESET and GLOBAL_ERASE, are similar to the corresponding independent key mode. In addition, the SET_PLAY, SET_REC and SET_ERASE commands allow users to specify the start and end of recording, playback and erasing. In addition, there are some commands that can access APC register to set the mode of chip analog input. The SPI serial interface operation of ISD 1700 series follows the following protocols:
The SPI process begins with the falling edge of the /SS pin. The /SS pin must remain low during a complete SPI instruction transmission cycle.
The data is latched at the MOSI pin of the chip on the rising edge of SCLK, output from the MISO pin on the falling edge of SCLK, and shifted out of the low bit first. The operation code of SPI instruction includes command byte, data byte and instruction byte, depending on instruction class 5 of 1760. When command words and data are input to MOSI pin, the status register and current line information are simultaneously removed from MISO pin. When /SS goes high, SPI process starts. After completing the SPI command operation, the interrupt message will start and remain low until the chip receives the CLR_INT command or the chip is reset.