MSP430i2041 FET JTAG problem "Unknown device"

Hi Michal,

Thanks for providing so much information - it is really helpful for narrowing down your issue. Looking at your schematic, the connections look correct for SBW, and the FET firmware version is new enough that it should support this device.

-Have you ever loaded code to these devices before (e.g. did it work once and then never again)? What code?

-Which code are you trying to load now - is it one of the TI code examples?

The reason I ask is that the i2xx parts are different from most MSPs in that they require the code project to have some Start-Up Code (SUC) included in them that runs at startup, and if this SUC is not included in the project then the part won't start up right and you'll have problems connecting to the device - if you use the provided code examples for the part from TI Resource Explorer MSPWare in CCS, you won't have a problem because this code is already included. There are also other reasons why previously-loaded code can make it hard to load new code (e.g. an error or WDT timeout causes the part to reset before the tool can get control of it) - so this is why I was wondering if the issue occurred even with parts that were never used before and were blank.

Another thing to try would be removing the 2.2nF pulldown Cap from the RST pin - just to see if this helps. The reason would be if there's a lot of other capacitance on this pin from long traces/wires it could maybe be causing issues with the timing for SBW on this pin.

Michal Rogowski said:

1) Can I keep JTAG pins 5(TMS), 3(TDI), 11(RST/NMI) floating or should I pull them to the GND? 

I always just leave them floating (except RST/NMI - this should be pulled up, but you need this pin for SBW connection anyway - it looks like it already has correct pullup R and pulldown C in your schematic). In software you can set the other (TMS, TDI) GPIO to be pulled high or low when you aren't in JTAG mode (or use them for some other function) - the JTAG function will override the GPIO setting when the TEST pin is pulled high by the FET tool - see www.ti.com/lit/pdf/slau320 as well as the device datasheet if you want more information about the TEST pin.

Michal Rogowski said:

2) How does FET detects that I'll be using the SBW instead of 4wire JTAG? 

In CCS, I believe it determines whether it should use either SBW or 4-wire JTAG by trying both of them and seeing if it gets the correct response from the device - it can put the device into either 4-wire JTAG or SBW mode by doing a different entry sequence on the TEST and RST pins (see http://www.ti.com/lit/pdf/slau320  for more information about how the FET works and entry sequences if you are curious). On some software tools like the Fet-Pro430 Lite software, you instead have to specify in the tool if you are using SBW or JTAG - it doesn't try both like CCS does. So it depends on the software being used.

Regards,

Katie