greeeg 460 Posted June 10, 2014 Share Posted June 10, 2014 Ohh, that's unfortunate. Did you try a 0 ohm? Recommended if you never intend to use the physical fuse blow feature. I don't have a problem changing the pin layout of my boards, but I would love to have the added benefit of a serial channel. Especially since now mspdebug has a bsl-driver that should work through a FET, I always seems to software disabling the JTAG on my FRAM ICs, and having to do a BSL erase to fix them. This serial channel obviously wouldn't be compatible with the default SPY-BI-TAG adapters. From what I can gather from perusing through the FET source code. If there is a voltage >1.7volts on the VIN pin, the UIF will create a internal voltage to match that is used to drive the programming pins. So if we place our RX pin on the TAG pin 4. The UIF will always be outputting VCC from TAG pin 2. The TEST/VPP pin is only driven when the user initiates a fuse blow, obviously putting the TX on this pin means that users can not use this feature. But if you are rewiring your target boards in this way they are also incompatible with this feature. I don't think it's such a loss, since alot of MSP's have a software fuse that will protect code. so we can place our TX pin on TAG pin 6? Proposed O RESET/SBWTDIO . . VCC (IN) [OUT from FET] TEST/SBWTCK . . RX (IN) [OUT from FET] GND . . TX (OUT) [IN to FET] O O If your target is self powered, don't connect the VCC pin? Another option could be to replace the SPY-BI-TAG connect with our own custom adapter, that could support the TX/RX serial lines? Quote Link to post Share on other sites
Fred 453 Posted June 10, 2014 Share Posted June 10, 2014 I'll try 0 ohm when I get home tonight, although it's a little confusing if that leaves the UIF open to damage. To me this note describes either using 330 ohm or effectively going with figure 2.3 (0 ohm to TCK and VPP not connected): R2 protects the JTAG debug interface TCK signal from the JTAG security fuse blow voltage that is supplied by the TEST/VPP pin during the fuse blow process. If fuse blow functionality is not needed, R2 is not required (populate 0 ?) and do not connect TEST/VPP to TEST/SBWTCK. You're right that serial would be useful and it's not possible with TagConnect's own SPY_BI_TAG adapter. It would be good if we can preserve some compatibility with it though. Not just because that's what I've started using, but because that's what somebody who's bought what TagConnect sell would get. I wonder if a couple of modifications to the SPY_BI_TAG would allow TX/RX to be connected as in your diagram? I can see reference to TX/RX being on pins 12 and 14 of the JTAG connector (figure B80 p154). Damn - I think the serial back channel is only supported on the new MSP-FET and not the FET430-UIF. Quote Link to post Share on other sites
spirilis 1,265 Posted June 10, 2014 Share Posted June 10, 2014 I think it would be good to switch it over to use TCK. And preserve the UART for non-FET430UIF users... I'll take a look at the schematic/etc again later to confirm @@greeeg 's layout. Quote Link to post Share on other sites
Fred 453 Posted June 10, 2014 Share Posted June 10, 2014 I'll add the TX/RX connections on my next test board. Whilst they won't work with the UIF, I can check that having them connected to the MCU doesn't interfere with its operation. Quote Link to post Share on other sites
Fred 453 Posted June 14, 2014 Share Posted June 14, 2014 Proposed O RESET/SBWTDIO . . VCC (IN) [OUT from FET] TEST/SBWTCK . . RX (IN) [OUT from FET] GND . . TX (OUT) [IN to FET] O O If your target is self powered, don't connect the VCC pin? Another option could be to replace the SPY-BI-TAG connect with our own custom adapter, that could support the TX/RX serial lines? I etched another board and can confirm this layout works fine with a FET430-UIF, a SBY_BI_TAG adapter and TagConnect cable. Connecting the TX/RX to the device doesn't interfere with operation either (but obviously doesn't do anything). greeeg 1 Quote Link to post Share on other sites
spirilis 1,265 Posted June 20, 2014 Share Posted June 20, 2014 Finally getting around to updating my diptrace footprints with this new pinout... coming up with an eZFET adapter board and revisiting my G2955 launchpad design with the new footprint. More to come! Quote Link to post Share on other sites
spirilis 1,265 Posted June 20, 2014 Share Posted June 20, 2014 eZFET Adapter board, updated to reflect the new pin locations (just ordered 6 from oshpark)- Gerbers: OSH_TC2030_eZFET_Adapter_v3_0.zip DipTrace footprints for TC2030 + SBW, optionally eZFET UART: TC2030-TI-SBW-eZFET.zip chicken and greeeg 2 Quote Link to post Share on other sites
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