# Title: RS232 Isolator 2 Click Board™ ## Description: How Does The RS232 Isolator 2 Click Board™ Work? The RS232 Isolator 2 Click Board™ as its foundation uses the ICL3221, a 3.3V powered RS232 transmitter/receiver that provides ±15kV ESD protection on its RS232 pins from Renesas. It features an automatic power-down function that occurs when the RS232 cable is removed and conserves system power automatically, and power-up again when a valid RS232 voltage is applied to any receiver input. It also ensures data rates greater than 250kbps even at worst-case load conditions. The RS232 Isolator 2 Click Board™ represents an isolated RS232 interface configuration using PS9121, an optically coupled high-speed active-low type isolator from Renesas, containing a GaAlAs LED on the input side, a photodiode, and a signal processing circuit on the output side rated for 3.75kV isolation and up to 15Mbps data rate. The RS232 transceiver ICL3221 is specified with a data rate of 250kbps and operates from a 3.0V to 3.6V external power supply header on the board's right side. In addition to the optocouplers, the TC7SZ125FU logic buffers from Toshiba Semiconductor are used to drive the necessary LED currents that usually cannot be provided by low-power MCUs or RS232 receiver outputs. The ICL3221 communicates with MCU using the UART interface with the default baud rate of 115200bps for the data transfer. It also comes equipped with the standard DB-9 connector, which makes interfacing with the RS232 simple and easy, and a red diode indicator labelled as INVALID indicates whether a valid RS232 signal is present or not. This diode always indicates whether a valid RS232 signal is present at any of the receiver inputs, giving the user a way to determine when the interface block should power down. If the interface cable is disconnected from the DB-9 connector and all the receiver inputs are floating, the ICL3221 detects invalid levels turning the LED. Reconnecting the cable restores valid levels at the receiver inputs, the diode turns off, and the power management logic wakes up the interface block. The RS232 Isolator 2 Click Board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before use with MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used, as a reference, for further development. SPECIFICATIONS Type Isolators, RS232 Applications Can be used for the isolation of RS-232 signals portable equipment, and where the low operational power consumption and even lower standby power consumption are critical. On-board modules ICL3221 - RS-232 transmitter/receiver that provides ±15kV ESD protection on its RS-232 pins from Renesas PS9121 - optically coupled high-speed active low type isolator from Renesas Key Features Low power consumption, automatic power-down, assured minimum data rate of 250kbps, an isolated RS-232 interface using Renesas digital high-speed optocouplers, and more. Interface UART Compatibility mikroBUS Click board size L (57.15 x 25.4 mm) Input Voltage 3.3V PINOUT DIAGRAM This table shows how the pinout of the RS232 Isolator 2 Click Board™ 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 NC NC 2 RST INT 15 NC NC 3 CS RX 14 TX UART TX NC 4 SCK TX 13 RX UART RX NC 5 MISO SCL 12 NC NC 6 MOSI SDA 11 NC Power Supply 3.3V 7 3.3V 5V 10 NC Ground GND 8 GND GND 9 GND Ground ONBOARD SETTINGS AND INDICATORS Label Name Default Description LD1 PWR - Power LED Indicator LD2 INVALID - Invalid RS232 Level LED Indicator J1 VISO Populated External Power Supply Header RS232 ISOLATOR 2 CLICK ELECTRICAL SPECIFICATIONS Description Min Typ Max Unit Supply Voltage - 3.3 - V External Supply Voltage VISO 3 3.3 3.6 V Isolation Voltage Range - - 3.75 kV Data Rate - - 15 Mbps Operating Temperature Range -40 +25 +85 °C ## Product type: Click Board ## Vendor: Mikroelektronika d.o.o. ## Tags: Click Board, Interface, MikroE, Renesas, RS-232, Serial Interface ## Price range: 22.4 - 22.4 GBP ## Link: https://thedebugstore.com/products/mikroe-4536-rs232-isolator-2-click-board-uk ## Compare-at price range: 32.0 - 32.0 GBP ## Options - Title: Default Title ## Collections - [New Products](https://thedebugstore.com/a/llms/collections/new-products-debug-store) - [Mikroelektronika d.o.o. 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- widget:The RS232 Isolator 2 Click Board™ as its foundation uses the ICL3221, a 3.3V powered RS232 transmitter/receiver that provides ±15kV ESD protection on its RS232 pins from Renesas. It features an automatic power-down function that occurs when the RS232 cable is removed and conserves system power automatically, and power-up again when a valid RS232 voltage is applied to any receiver input. It also ensures data rates greater than 250kbps even at worst-case load conditions.

The RS232 Isolator 2 Click Board™ represents an isolated RS232 interface configuration using PS9121, an optically coupled high-speed active-low type isolator from Renesas, containing a GaAlAs LED on the input side, a photodiode, and a signal processing circuit on the output side rated for 3.75kV isolation and up to 15Mbps data rate. The RS232 transceiver ICL3221 is specified with a data rate of 250kbps and operates from a 3.0V to 3.6V external power supply header on the board's right side. In addition to the optocouplers, the TC7SZ125FU logic buffers from Toshiba Semiconductor are used to drive the necessary LED currents that usually cannot be provided by low-power MCUs or RS232 receiver outputs.
The ICL3221 communicates with MCU using the UART interface with the default baud rate of 115200bps for the data transfer. It also comes equipped with the standard DB-9 connector, which makes interfacing with the RS232 simple and easy, and a red diode indicator labelled as INVALID indicates whether a valid RS232 signal is present or not.
This diode always indicates whether a valid RS232 signal is present at any of the receiver inputs, giving the user a way to determine when the interface block should power down. If the interface cable is disconnected from the DB-9 connector and all the receiver inputs are floating, the ICL3221 detects invalid levels turning the LED. Reconnecting the cable restores valid levels at the receiver inputs, the diode turns off, and the power management logic wakes up the interface block.
The RS232 Isolator 2 Click Board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before use with MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used, as a reference, for further development.
| Type | Isolators, RS232 |
| Applications | Can be used for the isolation of RS-232 signals portable equipment, and where the low operational power consumption and even lower standby power consumption are critical. |
| On-board modules | ICL3221 - RS-232 transmitter/receiver that provides ±15kV ESD protection on its RS-232 pins from Renesas PS9121 - optically coupled high-speed active low type isolator from Renesas |
| Key Features | Low power consumption, automatic power-down, assured minimum data rate of 250kbps, an isolated RS-232 interface using Renesas digital high-speed optocouplers, and more. |
| Interface | UART |
| Compatibility | mikroBUS |
| Click board size | L (57.15 x 25.4 mm) |
| Input Voltage | 3.3V |
This table shows how the pinout of the RS232 Isolator 2 Click Board™ 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 | NC | ||
| NC | 2 | RST | INT | 15 | NC | ||
| NC | 3 | CS | RX | 14 | TX | UART TX | |
| NC | 4 | SCK | TX | 13 | RX | UART RX | |
| NC | 5 | MISO | SCL | 12 | NC | ||
| NC | 6 | MOSI | SDA | 11 | NC | ||
| Power Supply | 3.3V | 7 | 3.3V | 5V | 10 | NC | |
| Ground | GND | 8 | GND | GND | 9 | GND | Ground |
| Label | Name | Default | Description |
|---|---|---|---|
| LD1 | PWR | - | Power LED Indicator |
| LD2 | INVALID | - | Invalid RS232 Level LED Indicator |
| J1 | VISO | Populated | External Power Supply Header |
| Description | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Supply Voltage | - | 3.3 | - | V |
| External Supply Voltage VISO | 3 | 3.3 | 3.6 | V |
| Isolation Voltage Range | - | - | 3.75 | kV |
| Data Rate | - | - | 15 | Mbps |
| Operating Temperature Range | -40 | +25 | +85 | °C |
We provide a library for the RS232 Isolator 2 Click Board™ and a demo application (example), developed using MikroElektronika compilers. The demo can run on all the main MikroElektronika development boards.
The package can be downloaded/installed directly from NECTO Studio The package Manager (recommended), downloaded from our LibStock™ or found on the mikroE Github account.
This library contains API for the RS232 Isolator 2 Click Board™ driver.
rs232isolator2_cfg_setup - Config Object Initialization function.rs232isolator2_init - Initialization function.rs232isolator2_default_cfg - Click the Default Configuration function.This library contains API for the RS232 Isolator 2 Click Board™ driver. This example transmits/receives and processes data from the RS232 Isolator 2 Click Board™. The library initialises and defines the UART bus drivers to send or receive data.
void application_task ( void ) {
#ifdef TRANSIVER
rs232isolator2_send_data( &rs232isolator2, demo_message );
log_printf( &logger, "%s", demo_message );
Delay_ms( 2000 );
log_printf( &logger, "------------------rn" );
#endif
#ifdef RECIEVER
rs232isolator2_process( );
if ( app_buf_len > 0 ) {
log_printf( &logger, "%s", app_buf );
rs232isolator2_clear_app_buf( );
}
#endif
}
The complete application code, and ready-to-use projects can be installed directly from NECTO Studio The package Manager (recommended), downloaded from our LibStock™ or found on the mikroE Github account.
Other mikroE Libraries used in the example:
Depending on the development board you are using, you may need a USB UART Click Board™, USB UART 2 Click Board™ or RS232 Click Board™ to connect to your PC for development systems with no UART to USB interface available on the board. The terminal available in all MikroElektronika compilers, or any other terminal application of your choice, can be used to read the message.
The RS232 Isolator 2 Click Board™ is supported with mikroSDK - MikroElektronika 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.
- device_vendor: Renesas Electronics America Inc, Toshiba Semiconductor and Storage - device_type: ICL3221ECVZ-T, TC7SZ125FU,LJ(CT - warranty: 12 months - brand: MikroE - manufacturer: Mikroelektronika d.o.o. - target_keyword: RS232 Isolator 2 Click Board - brands: gid://shopify/Metaobject/56256004319 - breadcrumbs: ["gid://shopify/Collection/447955239135","gid://shopify/Collection/241680580797","gid://shopify/Collection/241546100925"] - customhs_code: 847330 - detailed_description: {"type":"root","children":[{"type":"heading","level":3,"children":[{"type":"text","value":"How Does The RS232 Isolator 2 Click Board™ Work?"}]},{"type":"paragraph","children":[{"type":"text","value":"The "},{"type":"text","value":"RS232 Isolator 2 Click Board™","bold":true,"italic":true},{"type":"text","value":" as its foundation uses the ICL3221, a 3.3V powered RS232 transmitter/receiver that provides ±15kV ESD protection on its RS232 pins from Renesas. It features an automatic power-down function that occurs when the RS232 cable is removed and conserves system power automatically, and power-up again when a valid RS232 voltage is applied to any receiver input. It also ensures data rates greater than 250kbps even at worst-case load conditions."}]},{"type":"paragraph","children":[{"type":"text","value":""},{"type":"text","value":""},{"type":"text","value":""}]},{"type":"paragraph","children":[{"type":"text","value":"The "},{"type":"text","value":"RS232 Isolator 2 Click Board™","bold":true},{"type":"text","value":" represents an isolated RS232 interface configuration using PS9121, an optically coupled high-speed active-low type isolator from Renesas, containing a GaAlAs LED on the input side, a photodiode, and a signal processing circuit on the output side rated for 3.75kV isolation and up to 15Mbps data rate. The RS232 transceiver ICL3221 is specified with a data rate of 250kbps and operates from a 3.0V to 3.6V external power supply header on the board's right side. In addition to the optocouplers, the TC7SZ125FU logic buffers from Toshiba Semiconductor are used to drive the necessary LED currents that usually cannot be provided by low-power MCUs or RS232 receiver outputs."}]},{"type":"paragraph","children":[{"type":"text","value":"The ICL3221 communicates with MCU using the UART interface with the default baud rate of 115200bps for the data transfer. It also comes equipped with the standard DB-9 connector, which makes interfacing with the RS232 simple and easy, and a red diode indicator labelled as INVALID indicates whether a valid RS232 signal is present or not."}]},{"type":"paragraph","children":[{"type":"text","value":"This diode always indicates whether a valid RS232 signal is present at any of the receiver inputs, giving the user a way to determine when the interface block should power down. If the interface cable is disconnected from the DB-9 connector and all the receiver inputs are floating, the ICL3221 detects invalid levels turning the LED. Reconnecting the cable restores valid levels at the receiver inputs, the diode turns off, and the power management logic wakes up the interface block."}]},{"type":"paragraph","children":[{"type":"text","value":"The "},{"type":"text","value":"RS232 Isolator 2 Click Board™","bold":true},{"type":"text","value":" can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before use with MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used, as a reference, for further development."}]},{"type":"heading","level":3,"children":[{"type":"text","value":"SPECIFICATIONS"}]},{"type":"paragraph","children":[{"type":"text","value":"Type\nIsolators, RS232\nApplications\nCan be used for the isolation of RS-232 signals portable equipment, and where the low operational power consumption and even lower standby power consumption are critical.\nOn-board modules\nICL3221 - RS-232 transmitter/receiver that provides ±15kV ESD protection on its RS-232 pins from Renesas PS9121 - optically coupled high-speed active low type isolator from Renesas\nKey Features\nLow power consumption, automatic power-down, assured minimum data rate of 250kbps, an isolated RS-232 interface using Renesas digital high-speed optocouplers, and more.\nInterface\nUART\nCompatibility\nmikroBUS\nClick board size\nL (57.15 x 25.4 mm)\nInput Voltage\n3.3V"}]},{"type":"heading","level":3,"children":[{"type":"text","value":"PINOUT DIAGRAM"}]},{"type":"paragraph","children":[{"type":"text","value":"This table shows how the pinout of the "},{"type":"text","value":"RS232 Isolator 2 Click Board™","bold":true},{"type":"text","value":" corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns)."}]},{"type":"paragraph","children":[{"type":"text","value":"Notes\nPin\n\nPin\nNotes\nNC\n1\nAN\nPWM\n16\nNC\nNC\n2\nRST\nINT\n15\nNC\nNC\n3\nCS\nRX\n14\nTX\nUART TX\nNC\n4\nSCK\nTX\n13\nRX\nUART RX\nNC\n5\nMISO\nSCL\n12\nNC\nNC\n6\nMOSI\nSDA\n11\nNC\nPower Supply\n3.3V\n7\n3.3V\n5V\n10\nNC\nGround\nGND\n8\nGND\nGND\n9\nGND\nGround"}]},{"type":"heading","level":3,"children":[{"type":"text","value":"ONBOARD SETTINGS AND INDICATORS"}]},{"type":"paragraph","children":[{"type":"text","value":"Label\nName\nDefault\nDescription\nLD1\nPWR\n-\nPower LED Indicator\nLD2\nINVALID\n-\nInvalid RS232 Level LED Indicator\nJ1\nVISO\nPopulated\nExternal Power Supply Header"}]},{"type":"heading","level":3,"children":[{"type":"text","value":"RS232 ISOLATOR 2 CLICK ELECTRICAL SPECIFICATIONS"}]},{"type":"paragraph","children":[{"type":"text","value":"Description\nMin\nTyp\nMax\nUnit\nSupply Voltage\n-\n3.3\n-\nV\nExternal Supply Voltage VISO\n3\n3.3\n3.6\nV\nIsolation Voltage Range\n-\n-\n3.75\nkV\nData Rate\n-\n-\n15\nMbps\nOperating Temperature Range\n-40\n+25\n+85\n°C"}]},{"type":"heading","level":3,"children":[{"type":"text","value":" "}]}]} - summary:The RS232 Isolator 2 Click Board™ is a compact add-on board containing a fully isolated transceiver that provides secure and easy UART to RS-232 conversion. This board features the ICL3221, a 3.3V powered RS-232 transmitter/receiver that provides ±15kV ESD protection on its RS232 pins from Renesas. This Click Board™ is characterised by an assured minimum data rate of 250kbps. It features an automatic power-down function and uses high-speed digital optocouplers to isolate the RS-232 interface for 3.75kV isolation. It also possesses an LED indicator indicating a valid RS-232 signal at any receiver input. This Click Board™ is suitable for isolation of RS-232 signals portable equipment, where the low operational power consumption and even lower standby power consumption are critical.
The RS232 Isolator 2 Click Board™ is supported by a mikroSDK compliant library, which includes functions that simplify software development. This Click Board™ comes as a fully tested product, ready to be used on a system equipped with the mikroBUS™ socket.