TMC2310 DSP in underwater target detection and parameter estimation

　　1.2 Main functions

　　1.3 Structure and pins

　　TMC2310 consists of five main parts: two arithmetic units (AE0, AE1), on-chip coefficient ROM, control logic unit and external interface circuit. The logic block diagram is shown in Figure 1. Each arithmetic unit includes a multiplication sequence circuit and a multiply-add arithmetic logic circuit block. The chip uses an 88-pin PGA package.

The pin definition is as follows:

VDD VSS power input pin, using a single +5V power supply

CLK system clock input pin

　Read signal, active low level

　Write signal, active low level

SEMSEL external memory selection signal output pin

SCEN scaling output enable pin

DONE system work end flag output pin

CMD0~CMD1 control command input pins

W0~W16 dual-function data bus, used to input window functions, filter coefficients, and output the shift index of the scaler and the last overflow

AD0～AD9 external data memory address bus

RG0～RG18 real part bidirectional data bus

IM0～IM18 Imaginary part bidirectional data bus

　　1.4 Configuration register

　　There are two 16-bit configuration registers (CR1, CR2) in the TMC2310 chip, which are used to program the TMC2310. Their main purposes are as follows:

CR1 is used to set the processing function, conversion length, output format and scaling method of the chip;

CR2 is mainly used to set the addressing mode and the number of conversion channels (1 to 64 channels).

　　2 Circuit design

　　Since TMC2310 is a programmable dedicated DSP device, we use a TMS320C25 DSP device to cooperate with it, using a master-slave structure, parallel processing method, and a peripheral shared memory array to form a processing module. In addition to programming and controlling TMC2310, TMS320C25 also completes some subsequent processing and auxiliary operations (such as data extraction, integration, etc.) in the form of parallel computing. The entire circuit system adopts modular design to facilitate debugging and expansion. The schematic block diagram of the signal processing module is shown in Figure 2.

　　In Figure 2, a dual-port RAM array that works in a ping-pong manner is designed between TMC2310 and TMS320C25. It has four functions: (1) Store the data to be processed (the real part data is placed in the REM block, and the imaginary part data is placed in the REM block). IMM block); (2) stores the coefficients or parameters required by TMC2310 (placed in the WDM block); (3) stores the output results of TMC2310 and caches them as TMC2310 intermediate results; (4) constitutes the operation memory of TMS320C25. In order to facilitate the system construction and meet real-time needs, an IDT7025 dual-port RAM (8K×16) is used to form a RAM area shared between TMS320C25 and the outside world, so as to exchange and communicate data with the outside world in real time. This dual-port RAM area also works in a ping-pong manner to enhance the module's tolerance.

　　The ping-pong working mode control logic of the circuit is controlled by TMS320C25 according to the beat timing of the system. The control circuit ensures that CAA12 and CAB12 are mutually exclusive, and CAL12 and CAR12 are mutually exclusive. The entire circuit is simple, compact, coordinated and orderly. Due to the adoption of VLSI device design, the circuit design is greatly simplified, easy to debug, powerful, reliable in performance, and large in throughput (the data throughput rate of completing 1024-point FFT is 2.343M words/second).

　　3 Software design

　　The main tasks of TMS320C25 are: (1) Programming and control management of TMC2310 according to functional needs; (2) Exchanging data with TMC2310; (3) Complete some processing operations (such as sampling, integration, numerical and parameter calculations, etc.) ; (4) Communicate with the system (such as data input and output and the establishment of functions and methods, etc.). We divide these contents into different subroutines and design them according to modules, which is convenient for debugging and easy function expansion.

　　The software mainly consists of a main program and several subprogram modules. The main modules include: TMC2310 setting and control; communication with the outside; data output, data loading, coefficient loading and more than a dozen operation sub-modules. Due to limited space, only the main program flow chart is given below (see Figure 3).

　　Applying TMC2310 to the detection and estimation of underwater targets, it has the characteristics of fast speed, powerful functions, programmability, and easy operation. The signal processing module we developed using it is small in size and easy to expand. The system formed can work reliably in environments such as aircraft and ships. In the past few years, many tests and trials in pools, lakes and seas have proven that its design is reasonable and its application is successful, and it has been put into small batch production. In addition, it can also be used in many fields such as radar, communications and virtual instruments, and has good application prospects.