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Thread: PICAXE Input Pin Types

  1. #1
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    Default PICAXE Input Pin Types

    TTL ( Vsupply > 4.5V )

    Vih : >= 2.0V
    Vil : <= 0.8V

    TTL ( Vsupply <= 4.5V )

    Vih : >= 0.25 * Vsupply + 0.8V
    Vil : <= 0.15 * Vsupply

    Schmitt Trigger (ST)

    Vih : >= 0.8 * Vsupply ( >= 4V @ 5V )
    Vil : <= 0.2 * Vsupply ( <= 1V @ 5V )


    PICAXE-08 ( 12F629 )

    Serial In TTL

    In 1 TTL
    In 2 ST
    In 3 TTL
    In 4 TTL

    Vsupply = 2.2V to 5.5V ( 4MHz )


    PICAXE-08M ( 12F683 )

    Serial In TTL

    In 1 TTL
    In 2 ST
    In 3 TTL
    In 4 TTL

    Vsupply = 2.0V to 5.5V ( 4MHz, 8MHz )


    PICAXE-08M2

    Serial In TTL

    C.1 TTL
    C.2 ST
    C.3 TTL
    C.4 TTL
    C.5 TTL

    Vsupply = 2.3V to 5.5V ( 4MHz, 8MHz, 16MHz )
    Vsupply = 2.5V to 5.5V ( 32MHz )


    PICAXE-14M ( 16F684 )

    Serial In TTL

    In 0 TTL
    In 1 TTL
    In 2 TTL
    In 3 TTL
    In 4 TTL

    Vsupply = 2.0V to 5.5V ( 4MHz, 8MHz )


    PICAXE-14M2 ( Preliminary Information )

    Serial In TTL

    B.0 Output - C.0 TTL/ST - Configurable by 'inputtype'
    B.1 TTL/ST - C.1 TTL/ST
    B.2 TTL/ST - C.2 TTL/ST
    B.3 TTL/ST - C.3 TTL/ST
    B.4 TTL/ST - C.4 TTL/ST
    B.5 TTL/ST

    Vsupply = 1.8V to 5.5V ( 4MHz, 8MHz, 16MHz )
    Vsupply = 2.5V to 5.5V ( 32MHz )


    PICAXE-18 ( 16F627A )

    Serial In ST

    In 0 ST
    In 1 ST
    In 2 ST
    In 6 ST
    In 7 ST

    Vsupply = 3.0V to 5.5V ( 4MHz )


    PICAXE-18A / PICAXE-18M ( 16F819 )

    Serial In ST

    In 0 TTL
    In 1 TTL
    In 2 TTL
    In 6 ST
    In 7 ST

    Vsupply = 4.0V to 5.5V ( 4MHz, 8MHz )


    PICAXE-18M2 ( Preliminary Information )

    Serial In TTL

    B.0 TTL - C.0 TTL
    B.1 TTL - C.1 TTL
    B.2 TTL - C.2 TTL
    B.3 TTL
    B.4 TTL - C.4 TTL
    B.5 TTL - C.5 TTL
    B.6 TTL - C.6 TTL
    B.7 TTL - C.7 TTL

    Vsupply = 1.8V to 5.5V ( 4MHz, 8MHz, 16MHz )
    Vsupply = 2.3V to 5.5V ( 32MHz )


    PICAXE-18X ( 16F88 )

    Serial In ST

    In 0 TTL
    In 1 TTL
    In 2 TTL
    In 6 ST
    In 7 ST

    Vsupply = 4.0V to 5.5V ( 4MHz, 8MHz )


    PICAXE-20M ( 16F677 )

    Serial In TTL

    In 0 TTL
    In 1 ST
    In 2 ST
    In 3 ST
    In 4 ST
    In 5 ST
    In 6 TTL
    In 7 TTL

    Vsupply = 2.0V to 5.5V ( 4MHz, 8MHz )


    PICAXE-20M2 ( Preliminary Information )

    Serial In TTL

    B.0 TTL/ST - C.0 TTL/ST - Configurable by 'inputtype'
    B.1 TTL/ST - C.1 TTL/ST
    B.2 TTL/ST - C.2 TTL/ST
    B.3 TTL/ST - C.3 TTL/ST
    B.4 TTL/ST - C.4 TTL/ST
    B.5 TTL/ST - C.5 TTL/ST
    B.6 TTL/ST - C.6 TTL/ST
    B.7 TTL/ST - C.7 TTL/ST

    Vsupply = 1.8V to 5.5V ( 4MHz, 8MHz, 16MHz )
    Vsupply = 2.5V to 5.5V ( 32MHz )


    PICAXE-20X2 ( 18F14K22 )

    Serial In TTL

    C.0 TTL - B.0 TTL - A.0 TTL
    C.1 ST - B.1 TTL
    C.2 ST - B.2 ST
    C.3 ST - B.3 ST
    C.4 ST - B.4 ST
    C.5 ST - B.5 TTL
    C.6 TTL - B.6 TTL
    C.7 TTL - B.7 TTL

    Vsupply = 1.8V to 3.6V ( DC to 20MHz )
    Vsupply = 2.7V to 5.5V ( DC to 64MHz )


    PICAXE-28 / PICAXE-28A ( 16F872 )

    Serial In ST

    In 0 ST
    In 1 ST
    In 2 ST
    In 3 ST
    In 4 ST
    In 5 ST
    In 6 ST
    In 7 ST

    Vsupply = 4.0V to 5.5V ( DC to 20MHz )


    PICAXE-28X ( 16F873A )

    Serial In ST

    In 0 ST - PortA 0 TTL
    In 1 ST - PortA 1 TTL
    In 2 ST - PortA 2 TTL
    In 3 ST - PortA 3 TTL
    In 4 ST
    In 5 ST
    In 6 ST
    In 7 ST

    Vsupply = 4.0V to 5.5V ( DC to 20MHz )


    PICAXE-28X1 ( 16F886 )

    Serial In TTL

    In 0 ST - PortA 0 TTL
    In 1 ST - PortA 1 TTL
    In 2 ST - PortA 2 TTL
    In 3 ST - PortA 3 TTL
    In 4 ST
    In 5 ST
    In 6 ST
    In 7 ST

    Vsupply = 2.0V to 5.5V ( DC to 8MHz, internal resonator )
    Vsupply = 4.5V to 5.5V ( DC to 20MHz, external resonator )


    PICAXE-28X2 ( 18F25K22, 18F2520, 18F25K20 )

    18F25K22 = 28X2
    18F2520 = 28X2-5V
    18F25K20 = 28X2-3V

    Serial In ST

    C.0 ST - B.0 TTL - A.0 TTL
    C.1 ST - B.1 TTL - A.1 TTL
    C.2 ST - B.2 TTL - A.2 TTL
    C.3 ST - B.3 TTL - A.3 TTL
    C.4 ST - B.4 TTL
    C.5 ST - B.5 TTL
    C.6 ST - B.6 TTL
    C.7 ST - B.7 TTL

    Vsupply = 4.2V to 5.5V ( DC to 40MHz ) (5V voltage version)
    Vsupply = 1.8V to 3.6V ( DC to 64MHz ) (3V voltage version)


    PICAXE-40X ( 16F874A )

    Serial In ST

    In 0 TTL - PortC 0 ST - PortA 0 TTL
    In 1 TTL - PortC 1 ST - PortA 1 TTL
    In 2 TTL - PortC 2 ST - PortA 2 TTL
    In 3 TTL - PortC 3 ST - PortA 3 TTL
    In 4 TTL - PortC 4 ST
    In 5 TTL - PortC 5 ST
    In 6 TTL - PortC 6 ST
    In 7 TTL - PortC 7 ST

    Vsupply = 4.0V to 5.5V ( DC to 20MHz )


    PICAXE-40X1 ( 16F887 )

    Serial In TTL

    In 0 TTL - PortC 0 ST - PortA 0 TTL
    In 1 TTL - PortC 1 ST - PortA 1 TTL
    In 2 TTL - PortC 2 ST - PortA 2 TTL
    In 3 TTL - PortC 3 ST - PortA 3 TTL
    In 4 TTL - PortC 4 ST
    In 5 TTL - PortC 5 ST
    In 6 TTL - PortC 6 ST
    In 7 TTL - PortC 7 ST

    Vsupply = 2.0V to 5.5V ( DC to 8MHz, internal resonator )
    Vsupply = 4.5V to 5.5V ( DC to 20MHz, external resonator )


    PICAXE-40X2 ( 18F45K22, 18F4520, 18F45K20 )

    18F45K22 = 40X2
    18F4520 = 40X2-5V
    18F45K20 = 40X2-3V

    Serial In ST

    D.0 ST - C.0 ST - B.0 TTL - A.0 TTL
    D.1 ST - C.1 ST - B.1 TTL - A.1 TTL
    D.2 ST - C.2 ST - B.2 TTL - A.2 TTL
    D.3 ST - C.3 ST - B.3 TTL - A.3 TTL
    D.4 ST - C.4 ST - B.4 TTL
    D.5 ST - C.5 ST - B.5 TTL - A.5 ST
    D.6 ST - C.6 ST - B.6 TTL - A.6 ST
    D.7 ST - C.7 ST - B.7 TTL - A.7 ST

    Vsupply = 4.2V to 5.5V ( DC to 40MHz ) (5V voltage version)
    Vsupply = 1.8V to 3.6V ( DC to 64MHz ) (3V voltage version)

    Serial In Summary

    TTL = 08, 08M, 08M2, 14M, 18M2, 20M, 20X2, 28X1, 40X1

    ST = 18, 18A, 18M, 18X, 28, 28A, 28X, 40X, 28X2-3V/5V, 40X2-3V/5V


    Vsupply Summary

    4.5V to 5.5V = 28X1 (16/20MHz), 40X1 (16/20MHz)
    4.2V to 5.5V = 28X2-5V, 40X2-5V
    4.0V to 5.5V = 18A, 18M, 18X, 28, 28A, 28X, 40X
    3.0V to 5.5V = 18
    2.7V to 5.5V = 20X2 (32/64MHz)
    2.5V to 5.5V = 08M2 (32MHz)
    2.3V to 5.5V = 08M2 (4/8/16MHz), 18M2 (32MHz)
    2.2V to 5.5V = 08
    2.0V to 5.5V = 08M, 14M, 20M, 28X1 (4/8MHz), 40X1 (4/8MHz)
    1.8V to 5.5V = 18M2 (4/8/16MHz)
    1.8V to 3.6V = 20X2, 28X2-3V, 40X2-3V ( 4/8/16MHz )
    Last edited by hippy; 14-01-2013 at 22:33. Reason: Added 14M2, 20M2

  2. #2
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    Great list!

  3. #3
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    hippy, can you add the 28X (16F873A) and 40X(16F874A)? Serial In and Port C inputs are all ST.

    By coincidence, I found it out just this week. I am in the process of upgrading my current project from 28X (ST) to 40X1 (TTL) because I need the extra I/O and more programme space. I found my interrupts that worked on the 28X didn't interrupt on the 40X1. Luckily a small hardware mod overcame the problem.
    Last edited by inglewoodpete; 18-01-2008 at 04:49.

  4. #4

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    Excellent! Thanks for taking time to do this. I've copied and printed a hard copy for future reference.

    Rusty Bates

  5. #5
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    Added the missing 28, 28A, 28X, 40X, 28X2 and 40X2 parts, and also added information about Vsupply.
    Last edited by hippy; 18-01-2008 at 17:18. Reason: Forgot the 40X

  6. #6
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    Just to clarify, in the Vsupply Summary, are you saying that, for instance, the 28X1 running at 4/8MHz wants a minumum of 2.0V (and should be reliable at or above that), but at 16/20MHz wants 4.5V to 5.5V?

    Does this further imply that for, say, the 08M, the chip should be reliable running with DISABLEBOD down to 2V--below the approximately 3V at which Brown-Out Detection will turn the chip off? (That would say nothing, of course, about the viability of the rest of the circuit at 2V, or the risk that draw from a turned-on part could cause a dip below 2V.)

  7. #7
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    Quote Originally Posted by lbenson View Post
    Just to clarify, in the Vsupply Summary, are you saying that, for instance, the 28X1 running at 4/8MHz wants a minumum of 2.0V (and should be reliable at or above that), but at 16/20MHz wants 4.5V to 5.5V?
    Yes, that's what the official datasheets say. In practise you would probably get away with lower figures as the datasheet is quite conservative in it's figures.

    Yes to second question too (28X1 also has internal BOD to watch out for). However it may 'operate' but not 'download' at lower voltages.
    PICAXE Technical Support

  8. #8
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    Many thanks to Technical for the corrections and filling in the missing pieces ( especially all the additional port pins for the X1's / X2's ).

    Also to confirm that PICAXE's will often run lower than the minimum the datasheets state; I've run 18X's (4.0V-5.5V) at 3V3 without noticing any problems, but that doesn't mean it's always guaranteed. Best to use lower (4MHz) speeds when possible.

  9. #9
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    Re voltages.
    Found that a 28X1 will download at low voltages (that's because it switches to 4MHz for the download - doesn't it?).
    With setfreq em16 and an external resonator, it often starts at 4MHz if the voltage is anything around 4.25 or less - but sometimes it does start at 16MHz.

    If started at 16Mhz on say 4.5V, it seems to keep running down to 3.5V (there is not a lot of load on it) but will switch back to 4MHz if reset while on low power.
    Last edited by BCJKiwi; 20-01-2008 at 23:05.
    BCJ

  10. #10
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    Added PICAXE-20M to table.

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