manufacturing testing using MSP-FET430UIF

steve wenner said:

I have an array of 2x5 MSP4305328 boards that are being built in manufacturing.  I am trying to program them using SPI-BY wire interface with an MSP-FET430UIF.  I have a switch which supplies power from the UIF to the correct DUT.  The SPI-BY wire interface goes through an TS3A4741 switch.  These digital switches on the 9 other targets seem to allow the SPI-BY wire signals to pass through even with a pulldown resistor of 100k on the IN pins.  In essence it seems like the SPI-BY wire signals are back biasing the silicon switches somehow.  Does TI have a solution or recommended solution for using the MSP-FET430UIF to program one at a time an array of MSP430s over SPI-BY wire??

There are flashers with possibility of programing 8 target devices at once (in parallel) like MSP-GANG.

in SBW, TEST signal is for one-way communication (flasher > target), and selecting (or turning on/off) can be done for example with sn74lvc1g125/126 (or something similar). RESET signal is for two-way complication, and selecting (or turning on/off) can be done with logic that supports auto-direction sensing (right now, can't find right chip, but something like TXB0108).

(Maybe I am wrong) but I will not use analog switch (TS3A4741) for that.

Instead of MSP-FET430UIF, perhaps you may want to consider gang programmers.

SBW protocol is very sensitive to signal timing. Switches with auto-direction sensing are likely too slow to ensure a proper SBW operation. If at all, then an analog switch would be the better choice. Providing that its internal resistance as well as capacitance are low enough to not cause any timing problems.