中英文翻译

中英文翻译
ISD25120介绍
美国ISD公司的2500芯片，按录放时间60秒、75秒、90秒和120秒分成ISD2560、2575、2590和25120四种芯片，ISD2500系列和1400系列语音电路一样，具有抗断电、音质好，使用方便等优点。

它的最大特点在于片内E2PROM 容量为480K(1400系列为128K)，所以录放时间长；有10个地址输入端(1400系列仅为8个)，寻址能力可达1024位；最多能分600段；设有OVF（溢出）端，便于多个器件级联。

1.ISD25120管脚介绍：
电源（VCCA，VCCD）：模拟信号和数字信号电源端。

地线（VSSA，VSSD）：模拟信号和数字信号地线。

节电控制（PD）：该端拉高可使芯片停止工作而进入节电状态。

片选（CE）：低电平允许芯片工作。

录放模式（P/R）：一般在CE的下降沿锁存。

高电平选择放音，低电平选择录音。

溢出标志（OVF）：低电平以表示溢出，之后该端状态跟随CE端的状态变化
话筒输入（MIC）：麦克风输入端
话筒参考（MIC REF）：该端是前置放大器的反向输入。

自动增益控制（AGC）：ＡＧＣ可动态调整前置增益以补偿话筒输入电平的宽幅变化，这样在录制变化很大的音量（从耳语到喧嚣声）时就能保持最小失真。

模拟输出(ANA OUT)：前置放大器输出。

其前置电压增益取决于AGC端电平。

模拟输入(ANA IN)：该端为芯片录音信号输入。

扬声器输出（SP+、SP-）：扬声器输出端
辅助输入(AUX IN)：当CE和P/R为高，不进行放音或处入放音
溢出状态时该端的输入信号将通过内部功放驱动喇叭输出端。

外部时钟(XCLK)：该端内部有下拉元件，不用时应接地。

地址／模式输入（AX/MX）：地址端的作用取决于最高两位（MSB，即A8和A9）的状态。

当最高两位中有一个为0时，所有输入均作为当前录音或放音的起始地址。

地址端只作输入，不输出操作过程中的内部地址信息。

地址在CE的下降沿锁存。

当最高两位全为1时，A0～A6可用于模式选择。

2. ISD25120工作原理：
ISD25120有10个地址输入端A0—A9，录音地址能力可达到1024位，地址空间为0到1023，.其中0到299作为分段用，600到767未使用，768到1023
为工作模式。

ISD25120的地址用两种用途，一是作为工作模式，二是作为录放音的起始地址。

当A8、A9为高电平时地址A0—A6就作为工作模式端M0—M6，只要在录放音不少于300ns就给地址A0—A9赋值，操作就从此开始。

ISD25120语音芯片将480K的E2PROM分为600个信息，每800字节作为一段。

作为整体单位进行控制和寻址，每个信息段分配一个外部控制的地址，这样大大减少了信息检索需要的地址线。

对较长的语音信号可以跨越多个信息地址进行录音，不受内部的限制，而且内部的信息地址会自动增加。

在语音的结尾加一个EOM标志，通过检测EOM来控制各语音的结束和开始。

ISD25120的总时间为120s，而每个信息的录放时间为总时间除以600，这样每个信息的时候为200ms，因此可以用该时间长度作为一个地址段，通过单片机定时器的计时反映信息地址，从而得到录音的起始地址。

一般录音从0地址开始，首先通过CPU将它赋给A0—A9，然后控制ISD启动录音和单片机的定时器，每到一个信息段的时间就给地址计数器加1，当停止录音时同时也停止定时器的工作，此时地址计数器的值为该段语音的末地址，加一为下一段语音的首地址并将它存在E2PROM中，为下一个录放音提供信息，通过CPU赋给
A0—A9，即可以录制下段语音，依次下去，在录制完所有的语音地址信息时得到各段的首地址。

如果不是从0开始就将初始地址赋给A0—A9，加上地址计数器的值就可以得到该语音的末端地址。

因为每段都是相邻的，所以前一段的末端地址加一就是本段的起始地址而且每个语音的结尾都有EOM标志，而且可以发出中断。

放音时可以利用它和保存的E2PROM中的语音起始地址任意的组合各个语音段。

An Introduction of ISD25120
The 2500 chip of American ISD Company can be divided into four classes according to its playing time of 60 seconds, 75 seconds, 90 seconds and 120 seconds. They are ISD2560, 2575, 2590 and 25120. ISD2500 series is similar to Series1400 in perfect voice circuit, resisting power, and easy controlling. Its E2PROM capacity is 480K (Series1400’s is128K), which is its biggest characteristic. That is why its playing time is so long. It has 10 address inputs (Series1400 has only 8), and its addressing capacity is1024. It can be divided into 600 sections. It has an OVF (overflow) end, which can make the multiple devices to cascade with each other easily.
1. The introduction of ISD25120 pins:
Power supply (VCCA, VCCD): analog signal and digital signal power supply terminal.
Ground wire (VSSA, VSSD): analog and digital signal ground wires.
Power control (PD): the end is pulled high enables the chip to stop working and enters the power saving state.
Chip selection (CE): the low-voltage allows the chip to work.
Recording and Playing mode (P / R): General on the falling edge of CE latch. High-voltage selects playing, low-voltage selects recording.
Overflow flag (OVF): after low-voltage shows “overflow”,
the end will changes with the changing of the CE end state.
MIC input (MIC): microphone input.
Microphone reference (MIC REF): the end is the inverting input of the preamplifier.
Automatic gain control (AGC): AGC can dynamically adjust the microphone preamplifier gain to compensate for the input level width changes, such changes in recording a large volume (from a whisper to a noise) can maintain a minimum distortion.
Analog output (ANA OUT): the preamplifier output. The front end voltage gain depends on the level of AGC terminal.
Analog input (ANA IN): the end is a chip recording signal input.
Speaker output (SP +, SP -): speaker output
Auxiliary input (AUX IN): when the CE and P / R high, not playing or into the playback overflow state the ends of the input signal through an internal amplifier to
drive the speaker output.
External clock (XCLK): the end has an internal pull-down element, when the earth
Address / mode input (AX / MX): address end effect depends on the maximum of two (MSB, A8 and A9) state. When one of the top two is 0, all inputs are used as current recording or playback start address. Address end only for input, output during operation of the internal address information. Address at the falling edge of CE latch. When the top two for1, A0~ A6can be used for model selection.
2. ISD25120 working principles：
ISD25120 has 10 address inputs from A0 to A9, and its recorded access capacity can reach 1024, the address space is from 0 to1023. The address space from 0 to 299 is used for
section, 600 to767 is unused, and 768 to1023 is the working model. The ISD25120 address has two purposes .One is used as the working mode, the other as the sound recording start address. When A8, A9 is in high level, address A0 - A6 will work as M0- M6. As long as the sound recording value is not less than 300ns, it will warn address A0- A9, and the operation begins from then on.
The voice chip ISD25120 divides EEPROM of 480K into 600, and each 800 bytes as a segment. As a whole unit to control and address, each segment should get an external control address, thus reducing the need of address line when retrieval information. For the long speech signal it can span multiple information address to record, without the internal control, and internal information addresses will automatically increase. It will give an EOM mark in the speech end, and control the end and begin of the voice by detecting the EOM.
The total time of the ISD25120 is 120s. And each information recording time is the total time divided by 600, is 200ms. So it can be used as an address section, reflecting information addresses through the microcontroller timer, and obtain the recording start address. General recordings start from the 0 address, assign it to A0- A9 through the CPU, then controls the ISD to start the recorder and MCU timer. It will plus 1 to the address counter in each segment time. As soon as stopping recording, it stops the work of timer. At this time, the address counter value for this section is the end address of this speech section, plus one is the first address of the next speech segment and put it in EEPROM, which can give information for the next recording. Giving the information to A0- A9 through the CPU, it can record the next voice. Turning down, it will get the first
address of each section during the recording of all
the speech address information. If it do not give the initial address to A0- A9 at the beginning of 0, plus the address counter value can obtain the terminal voice address. Because each segment is adjacent, so the front section of the terminal address pluses one is this section start address and each speech end has an EOM mark, and can send an interrupt. Playback can use it and the EEPROM voice starting address to combine each speech segment arbitrarily.。