ISM RX 2 Click is a compact add-on board that contains a pin configurable, low current, sub-GHz EZRadio® receiver. This board features the Si4356, a standalone Sub-GHz RF receiver IC, from Silicon Labs, which provides a true plug-and-play receive option. The Si4356 features a (G)FSK/OOK demodulator, and it has a good sensitivity up to –113 dBm that allows longer operating range, while the low current consumption of 12 mA in Active and 50 nA in Stand-by Mode provides superior battery life. This Click board™ is suitable for remote low-speed communication, such as the remote keyless access, garage or gate doors control, industrial control, home automation, and similar applications where this kind of communication is applicable.

ISM RX 2 Click Click is supported by a mikroSDK compliant library, which includes functions that simplify software development.

ISM RX 2 Click is based on the Si4356, an easy-to-use, size efficient, low current wireless receiver IC, from Silicon Labs that covers the sub-GHz bands. The wide operating voltage range and low current consumption make the Si4356 an ideal solution for battery-powered applications. It has an integrated crystal oscillator and uses a single-conversion mixer to downconvert the (G)FSK or OOK modulated receive signal to a low IF frequency. The receiver demodulates the incoming data asynchronously by oversampling the incoming transmission, and the resulting demodulated signal send to the system MCU via the UART interface.

The Si4356 has a frequency range from 315 up to 917MHz and can be configured for operation using the four selector pins (SEL0 – SEL3) where the state of each of these pins is read internally at Start-Up and used to determine which pre-loaded configuration should be used. The SEL0 and SEL1 pins are used to adjust the frequency, and they are connected in such a way that the frequency of this Click board™ is fixed to 434.15MHz, while the setting of the SEL2 and SEL3 pins can be changed by using the SMD jumpers labeled as MODE SEL used to select the desired modulation (G)FSK or OOK. Additionally, this Click board™ has a low-pass RC filter on the receiver data output pin which is used to filter the output and improve sensitivity.

This Click board™ communicates with MCU using the UART interface for the data transfer, while the GPIO pins on the mikroBUS™ are used for mode selection and indication. More precisely, only one UART pin from the mikroBUS™ (RX) is used, for receiving the data. The Si4356 provides two operating modes: a Receive Mode and a Stand-by Mode. The operating mode can be changed by toggling the STBY signal routed to the CS pin on the mikroBUS™, while the MSTAT signal routed to the INT pin on the mikroBUS™ represents an interrupt and indicates the current operating mode of the device. It is also possible to reset the device by using RST pin routed to the RST pin on the mikroBUS™.

ISM RX 2 Click possesses on itself the SMA antenna connector with an impedance of 50Ω and it can be used for connecting the appropriate antenna for improved range and received signal strength.

This Click board™ is designed to be operated only with a 3.3V logic voltage level. A proper logic voltage level conversion should be performed before the Click board™ is used with MCUs with different logic levels.

• Interface: GPIO, UART
• Compatibility: mikroBUS™
• Dimensions: 42.9 x 25.4mm
• Input Voltage: 3.3V
• Supply Voltage: Min. -0.3V, Max. 3.6V
• ISM RX 2 Frequency Range: 434.15 MHz
• RX Mode Current: 12mA
• RX Input Power: +10 dBm
• Output Impedance: 50Ω
• Operating Temperature Range: Min. -40°C, Max. +85°C

• Schematic
• Si4356 Datasheet
• mikroSDK
• LibStock