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MSP430F2121 to 430G migration - Timer_A3

appleWiz
Prodigy 120 points
Other Parts Discussed in Thread: MSP430F2121

Hi Folks,

I am contemplating a move to the 'value line' for a product which uses the MSP430F2121. It uses Timer_A3 to generate pulses from the 'TA' pin. But the '430G23x2 family has completely mixed up the pins used for the timer I/O.

Is there any kind of guide or migration document for the 'G' series that might help me understand the change in the timer I/O pins please?

I cannot commit to a PCB layout until I am sure of the pin functions. Specifically the datasheet SLAS722E page 14 shows P1.1-3, suggesting a range of pins can be used, but there is no description of registers to select which pin?

Thanks,

Rob

 

  • Guru 227245 points

    The notation is still the same. Just the mapping to the pins has changed and needs to be adjusted inthe code.

    TA0 is TA0, TA1 is TA1 etc. (on chips with more than one timer, the notation is TA0.0 for TA0 of the first timerA and TA1.0 for TA0 of the second timerA.)

    The pin layout is part of the device datasheet. The pin functions are listed there on teh pin layout drawing as well as in a separate pin function table.

    Note that some of the G2 family members only have a Timer_A2 with two CCR units rather than 3, while the G2xx3 units have two Timer_A3.

  • in reply to Jens-Michael Gross
    Prodigy 120 points

    Hi Jens-Michael,

    >TA0 is TA0, TA1 is TA1 etc. (on chips with more than one timer, the notation is TA0.0 for TA0 of the first timerA and TA1.0 for TA0 of the second timerA.)

    I find these tables in TI datasheets very unclear. They have changed the notation to accommodate the 'G' series and it doesn't tie up well with the SLAU144 family datasheet.

     

    >The pin layout is part of the device datasheet. The pin functions are listed there on the pin layout drawing as well as in a separate pin function table.

    The pins are listed, but the table is not easy to understand. I have to use both the CCR0 input and output. On the '430G2312 the pins will have to be:

    P1.1 input

    P1.5 output

    But P1.5 clashes with the JTAG interface. I think the solution will be to rewrite my code to avoid using the CCR0 out0, and then choose one of the port2 basic I/O pins.

     

    >Note that some of the G2 family members only have a Timer_A2 with two CCR units rather than 3, while the G2xx3 units have two Timer_A3.

    I am using '430G2312, which states 3 capture/compare registers. So OK there at least!

     

    aW

  • in reply to appleWiz
    Guru 227245 points

    appleWiz said:
    They have changed the notation to accommodate the 'G' series and it doesn't tie up well with the SLAU144 family datasheet.

    Not only the G series. Other MSPs too have more than one TimerA now.  But since the old notation still exists, it is difficult to have both notations side-by-side in a documentation.
    However, neither one is or has ever been used as a symbol for coding (unlike the TimerA vectors), so one could assume that anyone who wants to deal with processor target board layout won't have problems to interpret the device datasheet. It's not rocket science, but also nothing I would recommend for electronics newbies. Some thinking is always required.

    appleWiz said:
    I have to use both the CCR0 input and output.

    At the same time? Sunds liek a conflict anyway. Either you input TA0.0 as a trigger or you output it as a PWM/trigger signal.
    On most MSPs with higher pin count, there's only one pin and both, input or output. But not shared then with anything else.

    appleWiz said:
    On the '430G2312 the pins will have to be:
    P1.1 input
    P1.5 output
    But P1.5 clashes with the JTAG interface

    P1.1 serves as output as well as input, for TA0CCR0, depending on the P1DIR.1 bit.
    P1.5 is an alternative output.
    P2.2 is an alternative input (which can be selected in the TACCFG0 register). So if you use P2.2 as input and P1.1 as output...

    Yes, checking the available hardware options before making a PCB is always a good idea.

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