Abstract: Proposed one kind carries on the control using the ATmega8 monolithic integrated circuit to the ISD2500 series speech chip the intelligence phonetic system, this system use is flexible, the easy function to promote, has the good application prospect. Has provided the hardware junction circuit and the essential source program.
Key word: Speech chip; Monolithic integrated circuit; Intelligent control; ISD2500
1 introduction
The language is the communication most direct tool. In industrial field, in traditional man-machine interaction, the people often through the numerical code demonstrated that the light, the electricity union receive the information which the machine sends out, this was decided by the technical level then. Along with the Semiconductor Technology and computer technology’s swift development, the pronunciation technology unceasingly is also making the breakthrough, particularly the speech synthesis technology better and better, the new speech chip is emerging unceasingly, American ISD Corporation produces the ISD2500 series speech chip is outstanding product. It may use the single chip control mode, may also use the microprocessor control mode.
2 ISD2500 series speech chip introduction
The ISD2500 series speech chip is one kind of high fidelity recording and sending out integration monolithic solid state pronunciation integrated circuit, has used the ISD Corporation’s patent “the direct simulation storage technology”, stores in successfully the semi-conductor memory the analog data. This unprecedented EEPROM storage method may read in directly the analog data the single memory cell, but does not need A/D or the D/A transformation. This kind of technology produces the effect is: (1) increased the integration rate compared to the same level digital form; (2) analog data’s memory does not volatilize. According to the recording and sending out time’s difference, the ISD2500 series chip may divide into ISD2560, 2575, 2590 and 25120 4 kind of models.
2.1 ISD2500 seals and pin function
ISD2500 uses the DIP-28 seal, pin arrangement as shown in Figure 1, pin function like table l arranges in order.
2.2 working patterns
When highest order address (MSB)A8, A9 for high level, the address end takes the operator schema choice end (high level effective). Its working pattern as shown in Table 2.
When use working pattern needs to pay attention to two points:
under (1) all working pattern’s operation is starts from the O address, later operation basis pattern difference, but starts from the corresponding address to work. When in the electric circuit records transfers the playback or enters the province electricity condition, the address counter replacement is 0.
(2) working pattern position does not lock decides, may when the MSB address position for the high level, the CE level changes the low any time execution working pattern operation. As soon as if under selects patches or strips of land as worth saving for seed in the cyclical MSB address position to have one (or two) becomes the low level, then carries out the information address, namely from this address sound recording or playback, originally hypothesis working pattern condition loss.
3 ISD2500 and monolithic integrated circuit’s connections and programming
The ISD2500 series speech chip structure is simple, the easy to operate, may constitute the simple single chip application system. But under many situations, because the pronunciation data’s record/puts needs by the other signal automatic control, therefore single chip’s ISD2500 cannot satisfy the application the request, by must use the micro controller’s phonetic system, the different working pattern will combine, according to needs the nimble record and broadcasts many information. ISD2500 may with each kind of micro controller constitution intelligence phonetic system. This article uses in Atmel Corporation AVR series monolithic integrated circuit’s ATmega8 is the example and ISD2500 constitutes a basic electric circuit, this electric circuit is a hardware platform, may act according to the various requirement to make the corresponding expansion.
Take the playback process as the example, its operating process is as follows:
on (1) component electricity;
the (2)PD end sets at the low level;
(3) input playback start address;
(4) waited for after the electricity retards (TPUD), causes CE origin Gao Biandi, drops along carries out the playback operation. This time the component no longer affects the address end and the recording and sending out control end jump once more, pays attention before CE changes low in control/address before write setup time (TSET), should maintain the above pin the stability;
(5) when meets the EOM symbol, the component continues to output the sound, when EOM pulse (TEOM) finished, the playback stopped.
Recording operation with playback operating process basic consistent, no longer gives unnecessary detail.
Concrete hardware junction circuit as shown in Figure 2. And S1 is “the sound recording” the key, S2 is “the broadcast” the key, S3 is “the section” operates the key.
Uses the monolithic integrated circuit carries on when the control to ISD2500 to pay attention to the following several points:
(1)ISD2500 series address before write setup time (TSET) is 300 ns, namely should guarantee the address signal, in CE drops before has 300 ns latencies. Some speed very quick monolithic integrated circuit needs to add the time delay.
(2)ISD2500 the series EOM pulse width’s typical value is 12.5 ms, when the playback may use the inquiry or the external interrupt way examines the EOM end the rise along, because only then, when after the EOM end becomes the high level, the CE signal can start the next operation. Its software flow as shown in Figure 3.
The essential source program is as follows:
4 concluding remark
The experiment proved that the ISD2500 series speech chip and the ATmega8 monolithic integrated circuit coordination use has received the good use effect. It may very relaxed carry on the expansion and the transplant, applies the robot voice prompt, the airplane automatic warning as well as systems and so on heart electrical signal in record playbacking, has the very broad application prospect.
