MUX Click

The MUX509 itself uses three control pins to perform signal switching. These pins are routed to the mikroBUS™, allowing simple interfacing with the host MCU. In addition, MUX click comes equipped with the three-pole terminal for the power supply, as well as with the standard 2.54mm 2×5 pin header for the input and output signals. This makes connecting all the wires simple and reliable, allowing the Click board™ to be operated right out of the box.

How does it work?

MUX click is equipped with the MUX509, a precise analog multiplexing IC, produced by Texas Instruments. The MUX509 can be used with a wide range of power supplies. It can handle both dual and single power supplies, as well as the symmetrical and non-symmetrical ones. This allows it to be used in a very wide range of different applications. Another property of the MUX509 IC is that it has dual inputs and dual output. Three control pins are used to switch one of four input pairs to a single output pair. Control pins labeled as A0 and A1 are routed to the mikroBUS™ and can be operated by both 3.3V and 5V MCUs. The third control pin is labeled as EN pin, used to enable the output when is set to a HIGH logic level (it is active HIGH). A0 and A1 pins are routed to RST and PWM pins of the mikroBUS™ respectively, while the EN pin is routed to the CS pin on the mikroBUS™.

The MUX509 IC is targeted towards working with differential signals, rather than working with the single-ended inputs. Each input is composed of two pins: SNA, and SNB, where N represents the channel number in the range from 1 to 4. When a specific channel is selected (N), both the SNA and SNB pins of that channel will be routed to the DA and DB output pins, respectively. For the improved stability, each signal pair is equipped with the 100nF parallel capacitor and 100Ω series resistance. The input and the output signal pins are routed to the standard 2.54mm pitch 2×5 pins header on the Click board™.

The ultra-low leakage current ensures that there is no signal interference from the inputs that are not selected by the A0 and A1 pins. A low crosstalk also ensures that the signal on one channel remains clean of interferences caused by other channels. To prevent any two inputs to be switched at the output at the same time, a break-before-make switching action is utilized. This ensures a reliable operation of the IC and the Click board™ itself.

MUX click does not use the power from the mikroBUS™ power rails, except for the LED indicator. Instead, a three-pole screw terminal is used to connect an external power supply. Having in mind the minimum input voltage of 10V or ±5V, a power supply should be connected to this terminal before operating the Click board™. Depending on the type of the used power supply (single supply or symmetrical/dual supply), it should be connected to the power supply input terminal, accordingly: GND is the reference ground connection, VSS is the negative voltage connection terminal (GND if a single power supply is used), and VDD is the positive voltage connection terminal. The input and output signals can be connected via the 2×5 pins header. As mentioned before, the MUX509 IC supports rail-to-rail operation, supporting input and output signals that  range from VSS (or GND) up to VDD. Independent power supply input allows the user to work with a wide range of signal amplitudes, depending on the application requirements, as long as the power supply stays within the limits.

More information about the MUX509 can be found in the attached datasheet. However, the Click board™ comes equipped with a library that contains easy to use functions and a usage example that may be used as a reference for the development.

Specifications

Pinout diagram

This table shows how the pinout on MUX Click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
	NC	1	AN	PWM	16	A1	Control pin 1
Control pin 0	A0	2	RST	INT	15	NC
Chip Enable	EN	3	CS	RX	14	NC
	NC	4	SCK	TX	13	NC
	NC	5	MISO	SCL	12	NC
	NC	6	MOSI	SDA	11	NC
	NC	7	3.3V	5V	10	5V	Power supply
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

MUX click electrical specifications

Software Support

We provide a library for the MUX Click as well as a demo application (example), developed using MIKROE compilers. The demo can run on all the main MIKROE development boards.

Package can be downloaded/installed directly from NECTO Studio Package Manager (recommended), downloaded from our LibStock™ or found on MIKROE github account.

Library Description

This library contains API for MUX Click driver.

Key functions

• Seelect active MUX channel

• Disable MUX device function.

• Enable MUX device function.

Example Description

Sets the current active channel. Changes the channel every 5 sec.

 void application_task ( void ) 
 { 
     uint16_t n_cnt; 

     for ( n_cnt = MUX_CHANNEL_1A_AND_1B; n_cnt < MUX_CHANNEL_END; n_cnt++ ) 
     { 
         log_printf( &logger, "      CHANNEL  S%urn", n_cnt ); 
         log_printf( &logger, "------------------------rn" ); 

         mux_active_mux_channel( &mux, n_cnt ); 
         Delay_ms ( 1000 );
         Delay_ms ( 1000 );
         Delay_ms ( 1000 );
         Delay_ms ( 1000 );
         Delay_ms ( 1000 ); 
     } 
 }

The full application code, and ready to use projects can be installed directly from NECTO Studio Package Manager (recommended), downloaded from our LibStock™ or found on MIKROE github account.

Other MIKROE Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.Mux

Additional notes and informations

Depending on the development board you are using, you may need USB UART click, USB UART 2 Click or RS232 Click to connect to your PC, for development systems with no UART to USB interface available on the board. UART terminal is available in all MIKROE compilers.

mikroSDK

This Click board™ is supported with mikroSDK – MIKROE Software Development Kit. To ensure proper operation of mikroSDK compliant Click board™ demo applications, mikroSDK should be downloaded from the LibStock and installed for the compiler you are using.

For more information about mikroSDK, visit the official page.