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MSP430F6779 4 wire SPI STE pin?

Berk CAKIR1
Prodigy 30 points
Other Parts Discussed in Thread: MSP430F6779

Hi,

I am using MSP430F6779 in my project. In datasheet, on Table 16 : Port Mapping Mnemonics and Functions, There is PM_UCXXSTE pins, but in Table 5 : Terminal Functions – PEU Package, There is no explanation about STE pin.

How can I use SPI Slave mode?

Where to connect the STE pin?

Best regards

Berk ÇAKIR

  • 0
    Guru 227245 points

    You should take a look into the users guide. It explains how the USCI module works.

  • 0 in reply to Jens-Michael Gross
    Prodigy 30 points

    Yes it explains how it works. There is no information abaout which pin(s) should I use for UCxSTE.

    about MSP430F471X7, I know which pin is STE. It is written in pin configuration but in MSP430F6779 there is no explanation about STE pin.

    is UCxSTE pin or register value? If pin which pin(s) have that function? If I can use anypin as STE, why it is not explained in Datasheet and User Guide

    "In 4-pin slave mode, UCxSTE is used by the slave to enable the transmit and receive operations and is rovided by the SPI master. When UCxSTE is in the slave-active state, the slave operates normally. When UCxSTE is in the slave- inactive state:

    • Any receive operation in progress on UCxSIMO is halted.
    • UCxSOMI is set to the input direction.
    • The shift operation is halted until the UCxSTE line transitions into the slave transmit active state.
    The UCxSTE input signal is not used in 3-pin slave mode. "

  • 0 in reply to Berk CAKIR1
    Guru 227245 points

    Berk CAKIR1 said:
    MSP430F6779 there is no explanation about STE pin.

    There is - just not where you are looking for it.

    If you take a closer look at the other pins with USCI function, you'll see that they are preceded by a "PM_". This means these pin functions are the default mapping for this pin, but can be remapped using the port mapping controller.

    The STE function, because seldom required, is by default not mapped to any pin. However, the mapping functions table in the port mapping controller section of the datasheet tells you which mapping value can be used to map this function to any mappable port pin.

    Berk CAKIR1 said:

    is UCxSTE pin or register value? If pin which pin(s) have that function? [...]The UCxSTE input signal is not used in 3-pin slave mode. "


    Neither pin nor register value. It is a signal, as you quoted yourself from the datasheet. Signals can come from a register bit, an input pin (if mapped) or an internal state or module output.
    However, due to the function of the STE signal, as explained in the users guide, only an external input makes any sense.

  • 0 in reply to Jens-Michael Gross
    Prodigy 30 points

    Now, I know what "PM" means. :)

    Thank you.

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