The RS232 3 Click Board™ as its foundation uses the SP3221E, a low power, RS232 transceiver (single driver/single receiver) solution with a 250kbps data rate from MaxLinear. The SP3221E uses an internal high-efficiency, charge-pump power supply and is compliant with EIA/TIA-232-F standards when powered by any of the mikroBUS™ power rails. This charge pump and MaxLinear's driver architecture allow the SP3221E to deliver compliant RS-232 performance from a single power supply intended for portable or handheld applications such as embedded computers, data logging devices, medical diagnostics, and remote sensors.
The SP3221E 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 LED indicator labelled as STATUS that indicates whether a valid RS232 signal is present not. This signal is also routed to the INT pin of the mikroBUS™ socket, labelled as STA. Alongside UART communication, several signals connected to the mikroBUS™ socket pins are also used to forward the information to the MCU.
For proper operation of SP3221E, this board uses a combination of two pins, EN and SHD pins routed to the CS and RST pins of the mikroBUS™ socket. The receiver is active when the AUTO ON-LINE® circuitry is enabled or when in Shutdown. The AUTO ON-LINE® feature, controlled via ON pin routed to the PWM pin of the mikroBUS™ socket, allows the SP3221E to automatically "Wake-Up" from a Shutdown state when an RS232 cable is connected, and a peripheral device is turned on. During the Shutdown, the receiver will continue to be active. If there is no activity at the receiver for a more extended period or when the SHD pin is enabled, the device goes into a Standby mode. Also, driving the EN pin to a high state forces the receiver's output into a high impedance state.
The RS232 3 Click Board™ can operate with both 3.3V and 5V logic voltage levels selected via the VCC SEL jumper. This way, it is allowed for both 3.3V and 5V capable MCUs to use the communication lines properly. However, the Click board™ comes equipped with a library that contains easy-to-use functions and an example code that can be used, as a reference, for further development.
| Type | RS232 |
| Applications | The RS232 3 Click Board™ can be used for low-power serial communications, portable serial devices, point-of-sale equipment, and many more applications |
| On-board modules | SP3221E - low-power RS232 transceiver from MaxLinear |
| Key Features | EIA/TIA-232-F standards, AUTO ON-LINE® circuitry automatically wakes up from a shutdown, minimum 250kbps data rate under load, Regulated charge pump yields stable RS-232 outputs regardless of power supply, and more |
| Interface | UART |
| Compatibility | mikroBUS |
| Click board size | L (57.15 x 25.4 mm) |
| Input Voltage | 3.3V or 5V |
This table shows how the pinout of the RS232 3 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 | ON | AUTO ON-LINE® | |
| Shutdown | SHD | 2 | RST | INT | 15 | STA | RS232 Signal Status |
| Enable | EN | 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 | 5V | Power Supply |
| Ground | GND | 8 | GND | GND | 9 | GND | Ground |
| Label | Name | Default | Description |
|---|---|---|---|
| LD1 | PWR | - | Power LED Indicator |
| LD2 | STATUS | - | Valid RS232 Signal LED Indicator |
| JP1 | VCC SEL | Left | Logic Level Voltage Selection 3V3/5V: Left position 3V3, Right position 5V |
| Description | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Supply Voltage | 3.3 | - | 5 | V |
| Data Rate | 250 | - | - | kbps |
| Operating Temperature Range | -40 | +25 | +85 | °C |
We provide a library for the RS232 3 Click Board™ as well as 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 RS232 3 Click driver.
Key functions
rs2323_generic_writeThis function writes a desired number of data bytes by using UART serial interface.
rs2323_generic_readThis function reads a desired number of data bytes by using UART serial interface.
This example demonstrates the use of the RS232 3 Click Board™ by showing the communication between the two click board configured as a receiver and transmitter.
void application_task ( void )
{
#ifdef DEMO_APP_TRANSMITTER
rs2323_generic_write( &rs2323, DEMO_TEXT_MESSAGE, strlen( DEMO_TEXT_MESSAGE ) );
log_printf( &logger, "%s", ( char * ) DEMO_TEXT_MESSAGE );
Delay_ms( 3000 );
#else
uint8_t rx_data;
if ( rs2323_generic_read( &rs2323, &rx_data, 1 ) > 0 )
{
log_printf( &logger, "%c", rx_data );
}
#endif
}
The full 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 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, 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 MikroElektronika compilers.
The RS232 3 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.
- manufacturer: Mikroelektronika d.o.o. - warranty: 12 months - backorder_label: If no stock shown above, check availability - attachments: [{"download_file":[{"download_file":"RS232 3 Click Board™ Schematic"}],"download_filetype":[{"download_filetype":"pdf"}]},{"download_file":[{"download_file":"MaxLinear SP3221E RS-232 Transceiver Datasheet"}],"download_filetype":[{"download_filetype":"pdf"}]}] - subtitle: RS-232 Transceiver with Auto-Start - feature_1: Based on the SP3221E - low-power RS232 transceiver from MaxLinear - feature_2: EIA/TIA-232-F standards, AUTO ON-LINE® circuitry automatically wakes up from a shutdown, minimum 250kbps data rate under load, Regulated charge pump yields stable RS-232 outputs regardless of power supply, and more - feature_3: Can be used for low-power serial communications, portable serial devices, point-of-sale equipment, and many more applications - mpn: MIKROE-5109 - mpn: MIKROE-5109 - custom_label_0: Click Board - google_product_category: Electronics - condition: new - custom_product: false - key_feature_2: EIA/TIA-232-F standards, AUTO ON-LINE® circuitry automatically wakes up from a shutdown, minimum 250kbps data rate under load, Regulated charge pump yields stable RS-232 outputs regardless of power supply, and more - key_feature_3: Based on the P3221E - low-power RS232 transceiver from MaxLinear - key_feature_4: Can be used for low-power serial communications, portable serial devices, point-of-sale equipment, and many more applications - key_feature_5: mikroBUS: UART Interface - device_vendor: MaxLinear, Inc. - device_type: SP3221EEA-L/TR - warranty: 12 months - brand: MikroE - manufacturer: Mikroelektronika d.o.o. - target_keyword: RS232 3 Click Board - brands: gid://shopify/Metaobject/56256004319 - breadcrumbs: ["gid://shopify/Collection/447955239135","gid://shopify/Collection/241680580797"] - customhs_code: 847330 - detailed_description: {"type":"root","children":[{"type":"heading","level":3,"children":[{"type":"text","value":"How Does The RS232 3 Click Board™ Work?"}]},{"type":"paragraph","children":[{"type":"text","value":"The "},{"type":"text","value":"RS232 3 Click Board™","bold":true,"italic":true},{"type":"text","value":" as its foundation uses the SP3221E, a low power, RS232 transceiver (single driver/single receiver) solution with a 250kbps data rate from MaxLinear. The SP3221E uses an internal high-efficiency, charge-pump power supply and is compliant with EIA/TIA-232-F standards when powered by any of the mikroBUS™ power rails. This charge pump and MaxLinear's driver architecture allow the SP3221E to deliver compliant RS-232 performance from a single power supply intended for portable or handheld applications such as embedded computers, data logging devices, medical diagnostics, and remote sensors."}]},{"type":"paragraph","children":[{"type":"text","value":""}]},{"type":"paragraph","children":[{"type":"text","value":"The SP3221E 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 LED indicator labelled as STATUS that indicates whether a valid RS232 signal is present not. This signal is also routed to the INT pin of the mikroBUS™ socket, labelled as STA. Alongside UART communication, several signals connected to the mikroBUS™ socket pins are also used to forward the information to the MCU."}]},{"type":"paragraph","children":[{"type":"text","value":"For proper operation of SP3221E, this board uses a combination of two pins, EN and SHD pins routed to the CS and RST pins of the mikroBUS™ socket. The receiver is active when the AUTO ON-LINE® circuitry is enabled or when in Shutdown. The AUTO ON-LINE® feature, controlled via ON pin routed to the PWM pin of the mikroBUS™ socket, allows the SP3221E to automatically \"Wake-Up\" from a Shutdown state when an RS232 cable is connected, and a peripheral device is turned on. During the Shutdown, the receiver will continue to be active. If there is no activity at the receiver for a more extended period or when the SHD pin is enabled, the device goes into a Standby mode. Also, driving the EN pin to a high state forces the receiver's output into a high impedance state."}]},{"type":"paragraph","children":[{"type":"text","value":"The "},{"type":"text","value":"RS232 3 Click Board™","bold":true},{"type":"text","value":" can operate with both 3.3V and 5V logic voltage levels selected via the VCC SEL jumper. This way, it is allowed for both 3.3V and 5V capable MCUs to use the communication lines properly. However, the Click board™ comes equipped with a library that contains easy-to-use 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\nRS232\nApplications\nThe RS232 3 Click Board™ can be used for low-power serial communications, portable serial devices, point-of-sale equipment, and many more applications\nOn-board modules\nSP3221E - low-power RS232 transceiver from MaxLinear\nKey Features\nEIA/TIA-232-F standards, AUTO ON-LINE® circuitry automatically wakes up from a shutdown, minimum 250kbps data rate under load, Regulated charge pump yields stable RS-232 outputs regardless of power supply, and more\nInterface\nUART\nCompatibility\nmikroBUS\nClick board size\nL (57.15 x 25.4 mm)\nInput Voltage\n3.3V or 5V"}]},{"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 3 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\nPin\nNotes\nNC\n1\nAN\nPWM\n16\nON\nAUTO ON-LINE®\nShutdown\nSHD\n2\nRST\nINT\n15\nSTA\nRS232 Signal Status\nEnable\nEN\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\n5V\nPower Supply\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\nSTATUS\n-\nValid RS232 Signal LED Indicator\nJP1\nVCC SEL\nLeft\nLogic Level Voltage Selection 3V3/5V: Left position 3V3, Right position 5V"}]},{"type":"heading","level":3,"children":[{"type":"text","value":"RS232 3 CLICK ELECTRICAL SPECIFICATIONS"}]},{"type":"paragraph","children":[{"type":"text","value":"Description\nMin\nTyp\nMax\nUnit\nSupply Voltage\n3.3\n-\n5\nV\nData Rate\n250\n-\n-\nkbps\nOperating Temperature Range\n-40\n+25\n+85\n°C"}]},{"type":"heading","level":3,"children":[{"type":"text","value":" "}]}]} - summary:The RS232 3 Click Board™ is a compact add-on board representing a universal usable RS232 transceiver. This board features the SP3221E, a low-power RS232 transceiver from MaxLinear. The SP3221E uses an internal high-efficiency, charge-pump power supply and is compliant with EIA/TIA-232-F standards when powered by any of the mikroBUS™ power rails. The AUTO ON-LINE® feature allows the SP3221E to automatically "Wake-Up" from a Shutdown state when an RS232 cable is connected and a peripheral device is turned on. When not connected or not in use, the SP3221E will automatically shut down, drawing less supply current. This Click board™ is suitable for low-power serial communications, portable serial devices, point-of-sale equipment, and many more applications.
The RS232 3 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.