A pin with 3 items in one function option really confuses me a lot!(K10)

[jelean]

It is a probles about Kinetis K10 MCU.

Usually when I want to configure a pin as the funcion I require,I need only call the following macro definition:

#define  IO_FUN_SEL(PTO, BIT, FUN)      \

    PCR(PTO,BIT) = (PCR(PTO,BIT) & (~PORT_PCR_MUX_MASK))|PORT_PCR_MUX(FUN) 

In this macro definition,the parameter FUN stands for the number sequence of function option and can be 0~7(stands for ALT0~ALT7),refer to the table below:

For example,if I want to configure the Pin PTC0(the 43rd pin) as the SPI0_PCS4,I need just define FUN as 2,namely the related code is:PORT_PCR_MUX(2).

Now please look at the Pin PTC2,there are 3 items(ADC0_SE4b,CMP1_IN0,TSI0_CH15) in the unit ALT0.

1)   So which funciton is really actived if I define the FUN as 0(PORT_PCR_MUX(0))  ?

2)   And ,if I want to configure the pin as the function wanted,what's the code?

Actually,I think that there are some other factors affecting the selection of pin function,but I can't find them.Who can tell me?

[adriansc · Accepted solution]

Hi,

In this cases these pins have multiple assignments in the same ALT configuration. The pin is configured in PCR register as 0 in MUX field: PORT_PCR_MUX(0) but after this in each module you need to select this configuration. I will use the PTC2 pin in order to explain this:

• PORTC_PCR2 = PORT_PCR_MUX(0);     //Enable ALT0 for portC2

               - If you want to use PTC2 as ADC0_SE4b you need to refer to ADCx registers, e.g:

                                ADC0_CFG2 = ADC_CFG2_MUXSEL_MASK;  //All ADxxb channels are selected

               - If you want to use PTC2 as CMP1_IN0 you need to refer to CMPx_MUXCR register, e.g:

                               CMP1_MUXCR = CMP_MUXCR_PSTM_MASK  //Pass Through Mode Eable enable, PTM is used

                                                                                                             //to enable to MUX pass through mode

                      Then you need to choose  between PSEL or MSEL fields, the Plus and Minus inputs respectively.

               - If you want to use PTC2 as TSI0_CH15 you need to refer to TSIx_PEN register, e.g:

                                 TSI0_PEN = TSI_PEN_PEN15_MASK;  //The corresponding pin is used by TSI

Hope this helps.

[jelean]

thanks a lot!:smileyhappy: