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TMS570LS3137: Pull up register values of MIBSPI pins

manzoor iftequar
Prodigy 95 points
Part Number: TMS570LS3137

I need clarity on below items

1. Push\pull setting of MIBSPI pins are applicable only if we use MIBSPI pins(CS,CLK,MOSI,SIMO) as GIO ?

2. In my project we are using MIBSPI functionality and as part of GIO code I am setting push\pull properties of all the peripherals pins used as pull enable and pull down.

including that of MIBSPI(CS,CLK,MOSI,SIMO).

But for (CS,CLK,MOSI,SIMO) pins I am seeing my setting in GIO code are not written into push pull register instead they are always pulled up.

on further investigation from datasheet I found the default pull state for MIBSPI pins which is mostly Pulled up

except for some pins Ex:

N2HET1[15]/MIBSPI1NCS[4] - default state is pulled down

But in pull select register of MIBSPI I always see MIBSPI1NCS[4] as pulled up.

Note : my code is using N2HET1[15] as GIO with pull down setting.

 

Can you clarify why the MIBSPI pull register says pulled up for pin N2HET1[15]/MIBSPI1NCS[4] ?

  • 0
    TI__Guru**** 186256 points

    If the ball N1 (N2HET1[15]/MIBSPI1NCS[4]) is used as MibSPI pin, the default pull-type is pull-up, and after reset the pull type is programmable.

    Is there a external pull on N2HET1[15]/MIBSPI1NCS[4] pin? 

  • 0 in reply to QJ Wang
    Prodigy 95 points

    Hi Wang,

    in that case datasheet SPNS162 Rev C is wrong to say default pull is pull down for (N2HET1[15]/MIBSPI1NCS[4])  ? Referring table 4-10 of SPNS162 Rev C.

    currently we have not connected anything on pin (N2HET1[15]/MIBSPI1NCS[4]) which is configured as input with pull down configuration.

  • 0
    Prodigy 95 points

    Hi Wang 

    any help on this ?

    I don't understand why my setting of pull enable and pull down for MibSPI pins are not working.

  • +1 in reply to manzoor iftequar
    TI__Guru**** 186256 points

    The pin N1 (N2HET1[15]/MIBSPI1NCS[4]) is pulled down after reset. The default functionality of pin N1 is N2HET1[15], and default signal direction is input. To pull this up, clear PDIS register, then write 1 to bit 15 of PSEL register. 

    To use this pin as MibSPI1CS[4],  pinmux should be configured:

    The default pull for MibSPI1CS4 is HIGH rather than DOWN (in datasheet), writing 0 to bit 4 of PSEL register will pull this pin to LOW.

    This is a literature bug in TMS570LS3137 datasheet.

    The correct statement should "PullHigh" for both N1 and P1 pin.