DSP System Design-Technical Issues

火辣西米秀

DSP System Design-Technical Issues [Copy link]

Q: I have two questions about C2000: 1. The RS reset pin of C240 or C2407 can be used for both input and output. Is it appropriate to drive it directly with a CMOS gate circuit (such as 74ACT04) or should it be driven with an OC gate (open collector)? 2. A large program sometimes runs abnormally, but it becomes normal after adding one or two empty instructions. What is the reason?

Answer: 1. OC gate (open collector) drive. 2. It is a pipeline problem.

Q: 1. Is there a single random function instruction in the DSP chip? 2. The calculation speed in the DSP is fast, but its I/O

How fast is the switching speed of the port? How does SP work with EPLD or FPGA?

A: 1. No. 2. It depends on the I/O you use. For HPI, the transfer rate (bytes) is about 1/4 of the CPU, and for McBSP, the bit rate (kbps) is about 1/2 of the CPU. 3. You can cascade the simulation interface and an EPLD/FPGA together.

Q: When designing a DSP system, I use the C6000 series. What is the principle of whether to pull up or pull down the DSP pins? I often hesitate when designing whether to set up/down resistors for a certain pin.

Answer: The input pins of the C6000 series generally have weak pull-up or pull-down resistors inside, so there is generally no need to consider adding external

Pull-up or pull-down resistors can be configured as needed in special cases.

Question: I am using TMS320VC5402 and downloading code through HPI, but C5402 only provides 16K words of internal storage area. Can I download the code to its external extended storage area through HPI and run it?

A: No, it can only be downloaded to the film.

Q: The circuit uses DSP. Sometimes when the reset signal is low, the voltage is also within the normal range, but the DSP fails to load the program. The current is also too large, and sometimes the clock is output. I don't know why?

A: The program cannot be loaded during reset.

Q: What issues should be paid attention to when connecting DSP and microcontroller to form a master-slave system?

A: It is recommended to use the HPI interface or connect via DPRAM.

Q: The original DSP program needs to be stored in EPROM, but the speed of EPROM is difficult to match that of DSP. How do you solve this problem now?

Answer: Use the BootLoad method to solve it.

Q: When I use 5402DSK, once it is powered on, without connecting the MIC, only connecting the earphones, and without running any programs, there is a relatively obvious noise of a certain frequency in the earphones. Sometimes it does not appear after powering on, but when the MIC is connected and the CODEC program in the example is run, this noise will appear again. The above situation usually disappears automatically after the DSK has been working for a period of time. I found on the DSP forum that others have also encountered this situation when using DSK. I made a board based on 5402DSK myself, and the components used are basically the same, and the same phenomenon occurs. What is going on? How to solve it?

Answer: There is no valid program code at the beginning, so it is in a random state after power-on. This is normal.

Q: I am using TMS320LF2407, but I cannot guarantee that I can always GO MAIN during simulation. I would like to know in detail how to set up the CMD file and the definition of VECTOR.

Answer: There may be a problem with the watchdog, turn off the watchdog. For more information about CMD file configuration, please refer to Chapter 2 of "Assembly Language Tools".

Q: When debugging the software on the TMS320VC5402 board I designed, memory error reports often appear. Excluding the mapping problem, is it the board's instability? Or is it the DSP's malfunction? How can I tell?

A: You can use the Memoryfill function to fill in some values, then refresh to see if it changes. If it does,

If it is changing, there is a problem with the memory.

Q: How to solve the problem of Flash programming: Can I first use the emulator to download to the external program storage RAM, and then the program code will write the program code from the external program storage RAM to the internal Flash ROM of F240? How to write it?

A: If you use F240, you can download the tool made by TI. Others can do this.

Q: How to access E1 signal through C5510 chip? What should I pay attention to when accessing?

Answer: Access through McBSP synchronous serial port. Note that the signal level must meet the requirements.

Q: How can I burn the .HEX program directly into FLASH through the emulator? If the DSP used is 5402, do I need to write a burning program myself? How can I achieve it? Thank you!!

Answer: Write .OUT directly. Write a program in DSP and write the main program into FLASH.

Q: What is the difference between DSP hardware design and other circuit boards?

Answer: 1. Consider timing requirements; 2. Consider EMI requirements; 3. Consider high speed requirements; 4. Consider power supply requirements.

Question: Among ADS7811, ADS7815, ADS8320, ADS8325, ADS8341, ADS8343, ADS8344, ADS8345, which one can be connected to VC33 more conveniently to complete the AD conversion of 10 analog signals (requires 16 bits, and the sampling of 10 signals must be completed within 1 millisecond. Of course, the price must also be considered)?

Answer: There are several points to consider when making a choice: 1. Total sampling rate: 1ms, 10 channels, total sampling rate is 100K, all A/Ds can meet the requirements. 2. Interface type between A/D and VC33: parallel, serial. The first two A/Ds are parallel interfaces, and the latter are serial interfaces. 3. Interface level matching. The first two A/Ds are 5V level and cannot interface with VC33; the latter are all 3.3V level and can directly interface with VC33.

Q: Sometimes the debugging success rate of the DSP circuit board is less than 50%, and there are no problems with the connection and the baseboard. How to solve it? Sometimes the DSP and CPLD have conflicts for unknown reasons. How to avoid it?

A: It seems that there may be something wrong with your hardware design, and the success rate should not be so small. The success rate of our board is over 95%.

Q: Two people are involved in the development of our project. Due to lack of consideration, one person used mnemonics to write the code.

Assembly code, another person uses algebraic symbols to write assembly code. How can these two writing methods be embedded together for debugging in CCS5000?

A: I have not used it this way. I think it can be solved by the following method: compile the program in one way into .obj separately.

obj files together with another type of program into the project, and the two can be compiled and debugged together.

Question: For DSP data buffering, can SDRAM be used instead of FIFO?

A: No

Q: What should be paid attention to when connecting ADC or DAC to DSP? For example, matching issues to ensure stable A/D sampling or no loss of D/A code.

Answer: 1. Interface mode: parallel/serial; 2. Interface level, the two must be consistent.

Q: When using F240, external interrupts are often lost. In the actual environment, the interrupts are only generated at the beginning of the program.

Sometimes the only way is to query. Is there any effective solution?

Is F2407 better?

Answer: It should have nothing to do with DSP. I suggest you simplify the interrupt service program.