MSP430F5638: Getting a USB CDC example running on the 5638

Hi Ted,

Could you refer the recommends in similar topic threads of below e2e link, it seems related to the drivers for the MSPFET detected by Device Manager:

(+) MSP430FR2355: MSP-FET430UIF is already in use - still crazy after all these years... - MSP low-power microcontroller forum - MSP low-power microcontrollers - TI E2E support forums

(+) MSP430FR6989: Error initializing emulator: MSP-FET430UIF is already in use - MSP low-power microcontroller forum - MSP low-power microcontrollers - TI E2E support forums

Regards,

Pengfei

Hi Pengfei,

Thanks for your response. The first problem is gone - the "MSP-FET430UIF is already in use" problem. I have no idea why it is gone, made no changes, just powered everything down & backup 3-4 times over 2 days. Now I can load prior working code and it runs fine on my MSP430F5638.

I still have question 2:

2. What do I need to change in this USB CDC C0_SimpleSend example to get it running on the 5638? I'm using PU for USB.

Hi Ted,

Have you try directly apply the USB example in F5638? There is no change needed about USB part, just need to change the device related part (such as pin definition) for migration.

I've looked through several files, and can't find it. Specifically which file(s) do I have to edit?

Hi Tes,

You do not need to make changes about USB driver. For example, the default USB example use P1.0 for LED output, and you could change it for your desired pin in F5638.

Have you try to directly apply the example in F5638, is there any error pop up?

YES, I'm building and loading to my custom SBC using the MSP430F5638. This board is working fine with a huge amount of code running on it. For this initial USB development, I'm ONLY building, loading, running the C0_SimpleSend example - no other code. It builds ok, seems to load ok - but I see nothing coming across USB to a terminal on the PC. As I previously stated, I'm not using ports P1 thru P9, I'm using the dedicated USB port PU.

I do see in Device Manager: Unknown USB device (Device Descriptor Request Failed)

What is the PID for MSP430F5638? And how do I do Device Descriptor?

Hi Ted,

Understood. 

For the PID modification, you could refer 2.6 Take Care if Changing the VIDs/PIDs  and Table 2. MSP430 USB API Application Examples, and PID Map of Examples Guide.

But basically, you do not need to change PID for a same type of USB example. Have you make any changes about the USB device class?

Hi Pengfei,

No changes, the properly working C0_SimpleSend project was copied from the 5529 workspace, to a 5638 workspace. The descriptors.h file is unchanged VID / PID = 0x2047 / 0x300. No code changes at all in the project.

My best guess is that I'm missing a step, that is already done, in the canned example. I can run the Descriptor Tool, but don't know what to do with it. How do I tie it to the new project? But if the VID / PID is the same, do I even need to run it?

Device Manager shows: Unknown USB device (Device Descriptor Request Failed)

Ted

Hi Ted,

I think you could check from hardware side. Please see 4 MSP430 USB Hardware Design Starting USB Design Using MSP430 for USB hardware design guide. Especially for XT2 oscillator, to make sure it has normal clock waveform in the oscillator.

My SBC msp430f5638 XT2 is running at 20 MHz with a crystal

The msp430f5529 launch pad XT2 uses a 4 MHz resonator

Looking in msp430f5638.h for USBPLL_SETCLK_xx_yy, there are no matches for 20 MHz, skips from 19.2 to 24 MHz

Where is USBPLL_SETCLK_xx_yy set in the code?

Do I have to change the XT2 crystal on my SBC?

Hi Ted,

You do not need to change the XT2 crystal you are using, and you could use PLL in MSP430 to generate desired 48MHz clock for USB, please refer  4.3 Selecting a Clock Configuration of Starting a USB Design Using MSP430 MCUs (Rev. B) for clock configuration.

I've read section 4.3 twice, it tells you nothing. Where is USBPLL_SETCLK_xx_yy set in the code?

There are too many steps, preset and not covered, in this canned example - C0_SimpleSend to get it running on a different MSP430 MCU.

This needs to be kicked up to a higher level of tech support.

Ted Fryberger said:

My SBC msp430f5638 XT2 is running at 20 MHz with a crystal

The msp430f5529 launch pad XT2 uses a 4 MHz resonator

Looking in msp430f5638.h for USBPLL_SETCLK_xx_yy, there are no matches for 20 MHz, skips from 19.2 to 24 MHz

For PLL setup you can use my attached calculator. Don't remember anymore what is acceptable USB PLL tolerance. If it is higher than 6410 than USB should work with 20 MHz XT2 just fine.

5582.MSP430USBCalc.zip

EDIT: 2500 ppm is max tolerance allowed by the USB specification, so unfortunately USB can not work with 20MHz XT2.

Thanks, so what is the max XT2 frequency for the MSP430F5638 and still work with USB?

Ted Fryberger said:

Thanks, so what is the max XT2 frequency for the MSP430F5638 and still work with USB?

19.2 MHz is crystal standard value close to 20MHz.

Thanks Zrno, I ran this for 20 MHz and confirmed your numbers - looks like I have to change XT2. Both 24, and 32 MHz look good with PLLCLK = 48 MHz, and ACC = 0 ppm.

How does -6410, compare to 0, and 2500 ppm? Why is it negative?