CCS/TMS320F28379D: TMS320F28379D controlCARD

Sabina,

Our USB expert is out of the office until next week. Because of this, I expect a delay in providing an answer until Tuesday. I will see if anyone can help you before he returns.

In the meantime if you can provide any additional details regarding the setup that may help provide a response (Dec 5th)

Regards
Lori

We use usb_dev_bul_cpu1 example as is (without any changes) and for improve USB speed communication  we try to change PLL speed from 50 MHz..

after any change of PLL  PC doesn't recognize  USB driver .

SysCtlClockSet(SYSCTL_OSCSRC_XTAL | SYSCTL_PLL_ENABLE | SYSCTL_IMULT(20) |

SYSCTL_SYSDIV(2));

SysCtlAuxClockSet(SYSCTL_OSCSRC_XTAL | SYSCTL_PLL_ENABLE |

SYSCTL_IMULT(12) | SYSCTL_SYSDIV(4));

What changes should be done here for increment PLL speed? Why this change influence to USB driver recognition from PC side?

Hi Sabrina,

For the USB to function on F2837xD, the AUX PLL needs to be clocked at 60MHz.

Also, we are not able to achieve the full 12Mbps. This is due to a couple of reasons. 1) To request more data (DATA IN packets) the host needs to send more requests. This may require OS kernel programming, and seems to be a limitation on the execution of the program on the Windows PC. 2) The USBlibrary is fairly complex on our C2000 devices. Because of the numerous function calls and cases to handle, the C2000 throughput is limited by its MIPS.

Regards,
sal

HI Sal ,
thank you , do you see any other way to speed up communication to the PC via USB ? any workaround to OS kernel limitation in a differnent confirguration ?
regards
Carlo

Hi Carlo,

I am unaware of a good way to speed up the OS kernel sending DATA IN packets.

I suggest using at least -O2 on the device MCU code though. This may give you some better performance on the C28x side. Make sure you are using compiler optimizations.

sal

Hi Sabrina,

You can hook up a USB analyzer to see how many packets are getting NAKed by the MCU or the PC. I doubt that the PC is dropping packets. I suspect the bottle neck is MIPS of the C2000.

I have achieved similar performance as you have. I profiled it by using the bulk device and a modified PC bulk example to test the throughput.

I am not sure what you are asking in regards to the interrupts. The USB examples do use interrupts.

You may like to try using SPI for your communication. You should be able to get some better performance.

sal

 Hi Sal,

Do you mean Millions of Instructions per Second - MIPS? Does it mean that we can not achieve 12Mbs with USB at all? What is the real max speed that we can achieve with USB with TMS320F28379D? Do you have any example that run with this speed ? Or send us what changes should be done for it...

Another question:

we can not install BULK driver of our embedded PC.

Did you have redistributable for Bulk driver install on PC embedded system?

Thanks,Sabina

Hi Sal,

in the post

https://e2e.ti.com/support/microcontrollers/c2000/f/171/p/419729/1495772

you wrote:.." We have been able to achieve throughput between 7 and 8 Mbps (875 KB/s - 1 MB/s) using bulk transfers with the F2837xD. This is slightly under the full speed maximum of 12Mbps. .."

Could you pls send us this example.

Thanks,Sabina

Sabrina,

Please try these ZIPs. There is a C2000 CCS project and a PC application. They have only been slightly modified from what is released in C2000Ware.

Regards,

sal

USB_Bulk_Stress_Test.zip

usb_dev_bulk_stress.zip

Hi Sal,

Thank you very much. I run your examples and get 6Mbs speed! it is enough good for us, but we have some additional questions:

1. Per spec we should achieve 12Mbs. Is it possible?
2. We can not install bulk driver on our embedded PC. Do you have any redistributable file for this driver? pls see systrace.txt with errors that we get:
   /cfs-file/__key/communityserver-discussions-components-files/171/systrace.txt

 Thanks,Sabina

Hi Sabrina,

That is good to hear?

1. As I have mentioned before, there are multiple possibilities for a bottleneck to greater throughput. Likely, it is is the C2000 processor speed which is the bottleneck.

2. Please see if a patch to the drivers work for you. See Lori Heustess' reply with a ZIP file on this thread. e2e.ti.com/.../646121

Regards,
sal

Hi Sal,

1. Processor speed is 200Mhz, and usb module requires 60 Mhz,  We need 12Mbs. Why  the processor speed is a bottleneck?

2. It doesn't help. We get the same problem.

1. The USBlib is fairly complex. There are many function calls which make it expensive (cycle wise) to execute.

2. Try uninstalling your drivers and then re-installing them. What OS are you using?

sal

Hi Sal,

In windows embedded 64 bits it work

In windows embedded 32 bits - doesn't 't work.

Thanks,Sabina

Hi Sal,

I have tried these example you posted but they haven't worked properly. The Visual Studio is stucked in the following line: 

dwError = ReadUSBPacket(hUSB, szBuffer, ECHO_PACKET_SIZE, &ulRead,INFINITE, NULL);   

being unable to receive any data from de DSP.

And the CodeComposer project, at one time, it seems that it jumps to a file called usbringbuf.c and stucks in here:

while(*pui32Val >= ui32Size)    // Line 101
{
*pui32Val -= ui32Size;
}

Please, could you tell me, if you know, what the problem could be with this?

Thank you very much

Make sure the C2000 is executing the proper CCS project. It should be doing nothing except writing to its USB Buffers to send data to the host PC when a DATA IN packets arrives.

sal