I2C_mux.c

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// DOCUMENTAZIONE DOXYGEN
/// \file 
 
/*! \page I2C_mux_page
*\brief  <span style="color:red;"> <b> The mux which distributes the I2C in the board  </b> </span>
*\tableofcontents
 
 \b SUMMARY:
*\arg \ref user_use_of_I2C_mux
 
 
*\section user_use_of_I2C_mux User use of I2C mux
<hr width="75%" size="10" align="left">
\n The managing of this chip is made with only one function, the I2C_mux_select_ch() with input parameters: <i> uint8_t scheda_su_scheda_giu, uint8_t I2C_mainboard, uint8_t  canale_da_abilitare</i>
that allows to select which of the 4 possibile I2C channels has to be used. The scheme od the mux, the \b TCA9546APWR, is as in \ref Figure_I2C_mux. It has a reset 
pin that is set as a first action at the call of the function. The chip has 4 I2C's to which send the input I2C. Thhe outpus can be individually activated or 
can be activated in parallel. Our choice is for the individual selection. Obviously, there is also the possibility to de-activate all the outputs.
\n The board manages 2 boxes so the first parameter \b scheda_su_scheda_giu is which of the boxes we want consider. \b scheda_su_scheda_giu 
can be \b 0 or \b 1.
\n The parameter  \b canale_da_abilitare allows to select which of the 4 channels is to be enabled: 
    - #I2C_mux_disabilita_tutto , this unset all the channels
    - #I2C_mux_abilita_0            , this enables channel 0
    - #I2C_mux_abilita_1                , this enables channel 1
    - #I2C_mux_abilita_2                , this enables channel 2
    - #I2C_mux_abilita_3                , this enables channel 3
 
\n The parameter \b scheda_su_scheda_giu allows to select which of the 2 board to communicate:
 -  #I2C_mux_Scheda_su
 -  #I2C_mux_Scheda_giu 
    
    \n Whenever the I2C is used, the I2C_mux must be set as a first step. Then, the I2C_mux is the last to be idled:
 
<span style="color:orange;"> <I>
\code {.c}
  function_which_set_some_device( I2C_mux_Scheda_su, device_to_set){
 
        I2C_mux_select_ch( I2C_mux_Scheda_su, I2C_mainboard,   I2C_to_enable_for_the_device);  //I2C_to_enable_for_the_device is any of the above I2C_mux_abilita_x
        
        //Now what we need to do
        
        I2C_mux_select_ch( I2C_mux_Scheda_su,  I2C_mainboard,  I2C_mux_disabilita_tutto);  //Now deselect the chip
    }
\endcode
</I> </span>
    
\n We set A0 to \b 1 in \ref Figure_I2C_address_of_I2C_mux below and the I2C address of the chip is then (considering that the 3 MSb are fixed to 1) \b 0x71:
 
*\anchor Figure_I2C_address_of_I2C_mux
*\image html I2C_address_of_I2C_mux.png "Figure_I2C_address_of_I2C_mux 1: I2C base address of I2C mux" width=30%
*\image latex I2C_address_of_I2C_mux.png "Figure_I2C_address_of_I2C_mux 1: I2C base address of I2C mux" width=30%
    
The address set on the mainboard is defined in:
 - #I2C_mux_address_mainboard.
 
 
 \n The datasheet of the I2C mux is here: <a href="./File_pdf/tca9546a_multiplexer_i2c.pdf"  target=_blank><b>TCA9546A datasheet</b></a> .
 
 The codes for mamnaging the mux are: 
 - \ref  I2C_mux.h  
 - \ref I2C_mux.c.
    
*\anchor Figure_I2C_mux
*\image html I2C_mux_TCA9546.png "FigureI2C_mux 2: I2C mux scheme" width=70%    
*\image latex I2C_mux_TCA9546.png "FigureI2C_mux 2: I2C mux scheme" width=70%   
 
 
 
<!-- pappa -->  
 
*/
 
 
#include "tutti_gli_header.h"
 
//#define I2C_mux_disabilita_tutto 0
//#define I2C_mux_abilita_0        1
//#define I2C_mux_abilita_1        I2C_mux_abilita_0 * 2
//#define I2C_mux_abilita_2        I2C_mux_abilita_1 * 2
//#define I2C_mux_abilita_3        I2C_mux_abilita_2 * 2
 
ARM_DRIVER_I2C * I2C_mux;
 
 
//Queste 2 andranno cancellate
uint8_t scheda_su_scheda_giu_provvisorio=I2C_mux_Scheda_giu;
volatile uint8_t scheda_su_scheda_giu=I2C_mux_Scheda_giu;
 
 
 /*! \brief The I2C mux
 
 *\param[in] scheda_su_scheda_giu one of the 2 boards that the postfrontend manages
 *\param[in] mainboard_postmainboard for selecting the I2C mux on mainboard, if I2C_mainboard, 
                         or postmainboard, if I2C_postmainboard
 *\param[in] canale_da_abilitare the channel of the mux to be enabled
 *\return No Parameters
 
 *\snippetlineno I2C_mux.c fun_I2C_mux_select_ch
 */
 //! <!-- [fun_I2C_mux_select_ch] -->
void I2C_mux_select_ch( uint8_t scheda_su_scheda_giu, uint8_t mainboard_postmainboard , uint8_t  canale_da_abilitare){
        tappo=0;
    if (scheda_su_scheda_giu==I2C_mux_Scheda_giu){ /* Determine which I2C to use for one board or the other */
        I2C_mux = &Driver_I2C1;  //board down
        GPIO_PinWrite(Reset_I2C_mux_down.porta_num, Reset_I2C_mux_down.pin_num, 0); //Let's reset the mux
        GPIO_PinWrite(Reset_I2C_mux_postfrontend_down.porta_num, Reset_I2C_mux_postfrontend_down.pin_num, 0); //Let's reset the mux of the postfrontend
        Aspetta_tanti_ms(2);
        GPIO_PinWrite(Reset_I2C_mux_down.porta_num, Reset_I2C_mux_down.pin_num, 1);
        GPIO_PinWrite(Reset_I2C_mux_postfrontend_down.porta_num, Reset_I2C_mux_postfrontend_down.pin_num, 1); //Let's reset the mux of the postfrontend
    }else if (scheda_su_scheda_giu>=I2C_mux_Scheda_su){
        I2C_mux = &Driver_I2C0;  //board up
        GPIO_PinWrite(Reset_I2C_mux_up.porta_num, Reset_I2C_mux_up.pin_num, 0); //Let's reset the mux
        GPIO_PinWrite(Reset_I2C_mux_postfrontend_up.porta_num, Reset_I2C_mux_postfrontend_up.pin_num, 0); //Let's reset the mux of the postfrontend
        Aspetta_tanti_ms(2);
        GPIO_PinWrite(Reset_I2C_mux_up.porta_num, Reset_I2C_mux_up.pin_num, 1);     
        GPIO_PinWrite(Reset_I2C_mux_postfrontend_up.porta_num, Reset_I2C_mux_postfrontend_up.pin_num, 1); //Let's reset the mux of the postfrontend     
    }
    
    //I2C_mux_address
    if ( (scheda_su_scheda_giu==I2C_mux_Scheda_giu)||(scheda_su_scheda_giu>=I2C_mux_Scheda_su)){
        if(mainboard_postmainboard==I2C_mainboard){
            I2C_mux -> MasterTransmit( I2C_mux_address_mainboard, &canale_da_abilitare, 1,false);
            while( I2C_mux -> GetStatus().busy);  // White transmission complete
            if( Error_bad_operation) ERROR_codifica_errore(scheda_su_scheda_giu, error_address_I2C0  , I2C_Error_I2C_mux, 1 );
            I2C_mux -> MasterReceive( I2C_mux_address_mainboard, &tappo, 1,false);  //Read back, not needed
            while( I2C_mux -> GetStatus().busy);
        }else if(mainboard_postmainboard==I2C_postmainboard){
            if(scheda_su_scheda_giu == I2C_mux_Scheda_giu){
                 //! <!-- [error_example] -->
                        I2C_mux -> MasterTransmit( I2C_mux_address_postmainboard_down, &canale_da_abilitare, 1,false);
                        while( I2C_mux -> GetStatus().busy);  // White transmission complete
                        if( Error_bad_operation) ERROR_codifica_errore(scheda_su_scheda_giu, error_address_I2C0  , I2C_Error_I2C_mux, 1 );
                //! <!-- [error_example] -->
                        I2C_mux -> MasterReceive( I2C_mux_address_postmainboard_down, &tappo, 1,false);  //Read back, not needed
                        while( I2C_mux -> GetStatus().busy);                
            }else{
                        I2C_mux -> MasterTransmit( I2C_mux_address_postmainboard_up, &canale_da_abilitare, 1,false);
                        while( I2C_mux -> GetStatus().busy);  // White transmission complete
                        if( Error_bad_operation) ERROR_codifica_errore(scheda_su_scheda_giu, error_address_I2C0  , I2C_Error_I2C_mux, 1 );
                        I2C_mux -> MasterReceive( I2C_mux_address_postmainboard_up, &tappo, 1,false);  //Read back, not needed
                        while( I2C_mux -> GetStatus().busy);                        
            }           
        }
    }
    
}
 //! <!-- [fun_I2C_mux_select_ch] -->