Part Number:MSP430F5659
Hi,
I'm trying to invoke the USB TI-BSL with a hard reset, but it looks like the device fails to enumerate (I get a "Device Descriptor Request Failed" in Windows' Device Manager).
I have attached a simplified version of the current circuit. Basically, we use USB on the MSP430 (not continuously), so D+ is pulled-up to USB_PUR with a 1.4k resistor. We have a button used with a GPIO, but if this button is pressed for more than 10 seconds, then a chip (U8 on the schematic) forces the RST_SBWTDIO of the MSP430 to 0V, thus resetting the device. When this reset occurs, we want to then connect the USB, release the button, and force the MSP430 to go into TI-BSL mode. From what I've read, I need to pull USB_PUR to VUSB through a 100 Ohm for that to happen.
Now, when I do this, I see that our main firmware isn't called after the device has reset, so the MSP430 is probably in the BSL, but it doesn't enumerate correctly via USB. Furthermore, if I have the USB already connected before entering the "hard reset" mode with the button, then even though the MSP430 is reset, it's still enumerated on the computer. It only disconnects when I release the button, then I get a "USB device not recognized".
What modification to the circuit do you suggest? Should the hard reset control the Vcc of the MSP430 instead of the RST_SBWTDIO?
Thank you,
Fred
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