The hottest sd178a integrated TTS processor and it

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Sd178a integrated TTS processor and its serial interface

Abstract: sda178 is an integrated "text to speech" (TTS) single chip processor launched by Taiwan Xiangyin company. The processor takes human voice as a sample, and the output voice is true and natural. The working principle and application of the processor are introduced, and the interface circuit and software program between sd178a and microprocessor are given

key words: text to pronunciation; Sd17 has a wide utilization range of 10 points 8A; Serial interface; Processor

1 introduction

with the development and application of computer and multimedia technology, the requirements for computer voice output are becoming more urgent and widely used. Speech is the most natural way of human interaction and the highest goal of the development of software user interface at this stage. Speech technology includes speech recognition and speech synthesis (text to speech). Speech recognition is used to tell the computer what we want it to do. And speech synthesis can let the computer tell us what it wants us to know. Using this technology can complete human-computer interaction. At present, whether in research or application, speech synthesis technology is in the period of development, and some have been put into practical application. The text to speech technology TTS (text to speech) and related products have also been promoted by many manufacturers, such as the pure software TTS processing software package (SAPI SDK package) launched by Microsoft, wts701 voice processing circuit launched by Huabang electronics, etc

sd178a is a single-chip TTS processor launched by Taiwan Xiangyin company. It uses human voice as a sample, and the output voice is true and natural. It can convert Chinese characters and ASC Ⅱ code into voice output. For example, sd178a can make many devices and daily necessities with voice function, such as talking GPS, talking three-way ammeter, talking sphygmomanometer, talking thermometer, talking books, etc

2 characteristics and working principle of sd178a

sd178a has the following characteristics:

● the working voltage range is 2.6v-5.2v

● the working current is only 1mA

● it has sleep power saving mode and wake-up function, and the standby current is only 1 μ A;

● set the mute time of punctuation and between words

● adopt single clock and RC oscillation mode

● contains 12 bit a/d converter and d/a converter

● support English male and female pronunciation and Chinese female pronunciation

sd178a's internal structure is shown in Figure 1. There is a 30 byte text buffer memory inside. The input Chinese or ASC Ⅱ code comes from the input end of sd178a and is temporarily stored in the text buffer. Sd178a will automatically convert the data in the text buffer into high-quality voice output in time, and clear the converted information stored in the buffer, In order to input the text continuously into the extended fatigue testing machine, which methods are entered into the text buffer

sd178a also provides a variety of control commands, such as stopping playback, pausing playback, restarting and adjusting the length of mute time between words (or between words and punctuation). In battery powered devices, power saving is very important. Sd178a not only provides the command and conversion function to enter the sleep power saving mode, but also provides pwdn pin, so that other devices connected with sd178a can also enter the sleep power saving mode in the sleep power saving mode of sd178a. The pin functions of sd178a are listed in Table 1

3 application of sd178a

3.1 the interface between sd178a and microprocessor

sd178a can be directly connected with other microprocessors, as shown in Figure 2. Ryd, SCLK and SDI in the figure are used for serial communication with the main controller. When RDY is at low level, it means that sd178a is in the state of accurately receiving data. SCLK changes from high level to low level, and sd178a will read the status signal of SDI line

3.2 TTS function of sd178a

the text waiting to be converted into speech is temporarily stored in the text buffer and processed by sd178a in sequence. In order to control this process, the system provides seven commands (as shown in Table 2). These commands have high priority and will be executed by the system first

3.3 control command code of sd178a output terminal

sd178a provides control command codes of two output terminals, namely 0x8a and 0x8b, which are respectively used to control the state of output terminals pa0-pa7 and pc0-pc5. The information code to be output immediately after command codes 0x8a and 0x8b (both 8 bits) is shown in Table 3, and the output timing of command codes 0x8a and 0x8b is shown in Figure 3

when using two command codes 0x8a and 0x8b, it should be noted that all the information to be converted into voice in sd178a buffer must be ready for processing; The information of b7-b0 in Table 2 will not be converted into speech, and will be output to pa7-pa0 and pc5-pc0 ports. The information of b7-b0 in Table 3 cannot be inserted between 0 and 1 codes of Chinese characters

3.4 sd178a software interface for realizing TTS function

sd178a software for realizing TTS function can be divided into main controller software interface and sd178a control interface, and their processes are shown in Figure 4 and figure 5 respectively

4 conclusion

compared with other forms of TTS, sd178a has many more humanized designs, such as setting the mute time of punctuation and between words, and the mute time can also be adjusted through setting, which makes people feel that there is a taste of emphasis or pause in tone, and it is more emotional to hear a signal from the workstation to control the movement of the actuator, Using the TTS voice circuit of sd178a, we can produce many products with the function of fixture sound prompt with language ② to some small experimental force, such as talking sphygmomanometers, talking thermometers, talking books, etc. (end)

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