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MSP <--> EMULATOR explanation

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I'm trying to understand the two possible configurations of the headers on the MSP430G2, rev 1.5, at the top near the border between the emulator and the uart.

 

The silk screen seems to indicate that one configuration is appropriate for hardware uart, and the other configuration is appropriate for software uart.

 

I'm wondering, why does it matter?  Whether using a software uart or chip with a hardware uart on board, either way doesn't the TX pin of the MSP still need to go to the RX pin of the emulator (likewise for RX-TX) in order to get data back and forth from a PC?

 

And when the direction is rotated, this seems even stranger since it looks like we're connecting TX-TX and RX-RX.  So what's really going on here?

 

Thanks

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The dedicated hardware pins, on the processors that have a hardware UART, such as the 2553, are swapped from the pins used by the software serial on the non-hardware UART devices. One position is for use with hardware UART *or* software serial that uses the same Tx and Rx as the hardware UART. The other position is for  use with the TI software serial Tx and Rx.

 

Why are they different? I don't know.

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I think I understand, but why don't they keep it at the same pins (software wise)so it's pin compatible? Just du make sure that the user is always aware that he is using hardware UART or software UART?

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The dedicated hardware pins, on the processors that have a hardware UART, such as the 2553, are swapped from the pins used by the software serial on the non-hardware UART devices. One position is for use with hardware UART *or* software serial that uses the same Tx and Rx as the hardware UART. The other position is for  use with the TI software serial Tx and Rx.

 

Why are they different? I don't know.

Thank you for fully answering the question.

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I think I understand, but why don't they keep it at the same pins (software wise)so it's pin compatible? Just du make sure that the user is always aware that he is using hardware UART or software UART?

 

No idea why the pins are swapped. If I were to make a guess, the G series software came before the hardware UART, and the way the hardware modules worked out ended up with exchanging the pins. I doubt it has anything to do with making sure the user knows what they are working with. More likely it has to do with parallel development between the software side and hardware side, and the use of standard macro cells and compatibility with previous devices for port assignment and hardware blocks, but that is only a guess.

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