Accuracy self-adapting continuous complicated wave form synthesis method

[0015] The present invention will be further described below in conjunction with the drawings and embodiments.

[0016] The equipment of the synthesis method includes a computer, a universal serial interface chip Cy7c68013, a DSP chip TMS320C6713 and a Sigma-Delta decoding chip TLV320AIC23. The computer is connected to the DSP through its USB interface and the universal serial interface chip Cy7c68013, and the DSP is connected to the DSP through the universal serial buffer interface McBSP. Connect the decoder chip TLV320AIC23.

[0017] The synthesis method is: the host's control command is sent to Cy7c68013, Cy7c68013 triggers the DSP to generate an interrupt, the DSP receives the corresponding control command, starts the program that has been loaded into the DSP, and the program generates the waveform type and related parameters according to the host's needs. The adaptive method calculates the length of the buffer, generates the corresponding discrete waveform and puts it into the buffer, and at the same time starts the McBSP that dynamically configures the EDMA parameters. The waveform is continuously output to TLV320AIC23 without the intervention of the DSP Core, and the required value is obtained at LOUT Continuous wave type.

[0018] The synthesis method includes the following steps: (1) the step of receiving synthesized waveform parameters from the USB interface; (2) the step of synthesizing adaptive precision waveform data; (3) the step of outputting the waveform; its feature is: the step of receiving the synthesized waveform from the USB interface The waveform parameter step refers to that the computer is connected to the D+ and D- of Cy7c68013 through its USB interface, Cy7c68013 is connected to the data line of DSP through address lines PD, PB, and the number of status lines is FLAGA, FLAGB, FLAGC and address lines EA5, EA4, and DSP of DSP. EA3 is connected as the address selection line of the endpoint buffer status register of Cy7c68013, SLRD, SLWR, SLOE are connected with DSP's ARE, AWE, AOE to control DSP peripherals, Cy7c68013's interrupt signal WU2 is connected to DSP's interrupt INT6, to be synthesized The waveform parameters are sent to the DSP along the channel, causing the DSP to generate interrupt 6, and receive the parameters, and transfer to the waveform synthesis step according to the preset DSP program; the adaptive precision waveform data synthesis step refers to the generation in the DSP buffer The length is L=f s *f d /f, where f s Is the sampling frequency, f d To normalize the frequency, f is the reciprocal of the signal period of any shape required by the user, when L=f s *f d When the result calculated by /f is not an integer or even an irrational number, then the buffer length should be adjusted according to the precision. The method is to use the formula L=f s *f d L and f in /f d At the same time magnify A times, if the frequency f precision required by the system is γ, then the selection of A is determined by A = AL L ≥ 1 γ Confirm that the number of cycles of the waveform generated in the buffer of length A·L at this time becomes A·f d , And then open up two buffers Ping_DA[] and Pong_DA[] in the DSP, respectively L1 and L2, and L=L 1 +L 2 , As the EDMA waveform data buffer, use the following algorithm to synthesize the waveform y(t)

[0019] for(i=0; i

[0020] {Ping_DA[i]=y(2*pi*fd*i/(L 1 +L 2 ))*0x7FFFFFFF;

[0021] Pong_DA[i]=y(2*pi*fd*(i+L/2)/(L 1 +L 2 ))*0x7FFFFFFF;

[0022] }; Among them, 0x7FFFFFFF is the 24-bit full-scale amplitude quantization value of AIC23. As long as the waveform function y(t) can be given, the corresponding waveform can be generated by the above algorithm; the step of outputting the waveform refers to the DSP through the universal string The line buffer interface McBSP is connected to the decoder chip TLV320AIC23 to output the waveform.

[0023] Such as figure 1 In, the computer is connected to the D+ and D- of Cy7c68013 through its USB interface, Cy7c68013 is connected to the data line of the DSP through the address lines PD and PB, and the number of status lines FLAGA, FLAGB, FLAGC is connected to the address lines EA5, EA4, EA3 of the DSP as The address selection line of Cy7c68013's endpoint buffer status register, SLRD, SLWR, SLOE are connected with DSP's ARE, AWE, AOE to control DSP peripherals, Cy7c68013's interrupt signal WU2 is connected to DSP's interrupt INT6, DSP is through the general buffer interface McBSP is connected to the decoding chip TLV320AIC23; when Cy7c68013 has a control instruction, it will trigger the DSP to generate an interrupt to start the program that has been loaded into the DSP, and receive the corresponding control instruction. The program generates the waveform type and related parameters according to the host's needs.

[0024] Such as figure 2 In the "Main Program Start", initialize the DSP frequency and peripheral ports, "Set I2C" port parameters, set TLV320AIC23 to asynchronous mode, enable the right channel output, and "McBSP1 parameter setting" to adopt frame synchronization, sending mode, configuration Sending register: one-way frame, the frame length is the number of elements plus 1, each element is 32Bit, the detailed configuration is as follows:

[0025] MCBSP_Config mcbspCfg1={

[0026] 0x30000000, //Serial Port Control Reg.(SPCR)

[0027] 0x00A000A0, //Receiver Control Reg.(RCR)

[0028] 0x00400140, //Transmitter Control Reg. (XCR)

[0029] 0x117F1F03, //Sample-Rate Generator Reg.(SRGR)

[0030] 0x00000000, //Multichannel Control Reg.(MCR)

[0031] 0x00000000, //Receiver Channel Enable(RCER)

[0032] 0x00000000,//Transmitter Channel Enable(XCER)

[0033] 0x00000F00 //Pin Control Reg.(PCR)

[0034] };

[0035] If the program is not closed, it will always wait for the interrupt INT6 in a loop; the interrupt "INT6" program first reads the "waveform parameters" from the host, "automatically generated buffer length" L = f s *f d /f, where f s Is the sampling frequency, fd is the normalized frequency, that is, the number of waveform cycles in the length L, f is the signal frequency required by the user, and then two buffers Ping_DA[] and Pong_DA[] are opened in the DSP, which are L1 And L2, and L=L 1 +L 2 , As the EDMA waveform data buffer, use the following algorithm to "waveform synthesis" for the function y(t)

[0036] for(i=0; i

[0037] {Ping_DA[i]=y(2*pi*fd*i/(L 1 +L 2 ))*0x7FFFFFFF;

[0038] Pong_DA[i]=y(2*pi*fd*(i+L/2)/(L 1 +L 2 ))*0x7FFFFFFF;

[0039] };

[0040] Among them, 0x7FFFFFFF is the 24-bit full-scale amplitude quantization value of AIC23. Take sine as an example. When fd is 3 and the output frequency is 750, the buffer length is 128. As long as the waveform function y(t) can be given, it can be The corresponding waveform is generated by the above algorithm. Note that L=f s *f d The result calculated by the /f formula may not be an integer, or even an irrational number. At this time, if only the integer part is taken, the generated waveform will be distorted. The buffer length should be adjusted according to the accuracy by combining L and f in the above formula d At the same time magnify A times, if the frequency accuracy required by the system is γ, the selection of A is A = AL L ≥ 1 γ Confirm that the number of cycles of the waveform generated in the buffer of length A·L at this time becomes A·f d , The amplitude of the output waveform is adjusted by the output amplitude of TLV320AIC23.

[0041] Such as image 3 In the “EDMA parameter setting”, the ping buffer (Ping_DA) and the pong buffer (Pong_DA) are connected end to end through the EDMA channel chain, and alternately send data to McBSP1. When one is sending data, the other receives the newly generated CPU Data, ensure the parallelism of sending and data processing, but when the buffer can store a full cycle of data, it is pre-generated during initialization, and DSP processing is no longer needed after entering the loop; when the data sampling rate is constant, change the two The length of the buffer changes the time length of the data waveform. EDMA and the channel chain are configured as a multi-channel link mode, and only the pong buffer length is changed every time a new waveform is generated; for the waveform that cannot be given the waveform function y(t) To generate, as long as the sampled data of a given waveform is sent to the DSP buffer by the USB interface of the computer, the signal can also be generated by the above technique.