ST Microelectronics Nucleo L4R5

The ST Nucleo L4R5 Nucleo Board features The STM32L4R5 Microcontroller, an ultra-low-power microcontrollers family (STM32L4+ Series) based on the high-performance Arm® Cortex®-M4 32-bit RISC core. They operate at a frequency of up to 120 MHz.

The STM32 Nucleo-144 board provides an affordable and flexible way for users to try out new concepts and build prototypes by choosing from the various combinations of performance and power consumption features, provided by the STM32 microcontroller.

The ST Zio connector and the ST morpho headers provide an easy means of expanding the functionality of the Nucleo open development platform with a wide choice of specialized shields. The STM32 Nucleo-144 boards do not require any separate probe as they integrate the ST-LINK/V2-1 debugger/programmer.

ST Nucleo L4R5

St Microelectronics Nucleo L4R5. Copyright

Pin Mapping

ST Nucleo L4R5 Pin Map

ST Nucleo L4R5 official manual is available here

Flash Layout

The internal flash of the ST Nucleo L4R5 is organized into two banks of 1Mb each. Each bank has sectors of different size according to the following table:

Bank 1 Bank 2
Start address Size Content Start address Size Content
0x8000000 16Kb Virtual Machine 0x8100000 16Kb Bytecode Bank 7
0x8004000 16Kb Virtual Machine 0x8104000 16Kb Bytecode Bank 8
0x8008000 16Kb Virtual Machine 0x8108000 16Kb Bytecode Bank 9
0x800C000 16Kb Virtual Machine 0x810C000 16Kb Bytecode Bank 10
0x8010000 64Kb Virtual Machine 0x8110000 64Kb Bytecode Bank 11
0x8020000 128kb Bytecode Bank 0 0x8120000 128kb Bytecode Bank 12
0x8040000 128kb Bytecode Bank 1 0x8140000 128kb Bytecode Bank 13
0x8060000 128kb Bytecode Bank 2 0x8160000 128kb Bytecode Bank 14
0x8080000 128kb Bytecode Bank 3 0x8180000 128kb Bytecode Bank 15
0x80A0000 128kb Bytecode Bank 4 0x81A0000 128kb Bytecode Bank 16
0x80C0000 128kb Bytecode Bank 5 0x81C0000 128kb Bytecode Bank 17
0x80E0000 128kb Bytecode Bank 6 0x81E0000 128kb Bytecode Bank 18

Device Summary

  • Microcontroller: ARM 32-bit Cortex™-M4 CPU Core
  • Operating Voltage: 3.3V
  • Input Voltage: 7-12V
  • Digital I/O Pins (DIO): 133
  • Analog Input Pins (ADC): 9
  • UARTs: 1
  • SPIs: 1
  • I2Cs: 1
  • Flash Memory: 2Mb
  • SRAM: 640Kbyte
  • Clock Speed: 120MHz


On the ST Nucleo L4R5, the power supply is provided either by the host PC through the USB cable, or by an external Source: VIN (7V-12V), E5V (5V) or +3V3 power supply pins on CN11 or CN8. In case VIN, E5V or +3V3 is used to power the Nucleo device, using an external power supply unit or an auxiliary equipment, this power source must comply with the standard EN-60950-1: 2006+A11/2009, and must be Safety Extra Low Voltage (SELV) with limited power capability.

The ST-LINK/V2-1 supports USB power management allowing to request more than 100 mA current to the host PC. All parts of the STM32 Nucleo device and shield can be powered from the ST-LINK USB connector CN1 (U5V or VBUS).


Depending on the type of power supply choosen, the jumper JP3 must be correclty selected:

  • JP3 between pin 1 and pin 2 for E5V power supply;
  • JP3 between pin 3 and pin 4 for U5V power supply (ST-Link VBUS);
  • JP3 between pin 5 and pin 6 for VIN-5V power supply.

Please refer to the datasheet of the Nucleo-144 boards for more information on Power selection and Power supply.

Connect, Register, Virtualize and Program

The ST Nucleo L4R5 Programming port is connected to the ST-Link uploader creating a virtual COM port on a connected computer. To recognize the device, Windows machines requires drivers that can be downloaded from the ST Nucleo download page, while MAC OSX and Linux machines will recognize the device automatically.

The St-Link is also connected to the STM32 hardware UART0.

Once connected on a USB port, if drivers have been correctly installed the ST Nucleo L4R5 device is recognized by Zerynth Studio and listed in the Device Management Toolbar. The next steps are:

  • Select the ST Nucleo L4R5 on the Device Management Toolbar (disambiguate if necessary);
  • Register the device by clicking the “Z” button from the Zerynth Studio;
  • Create a Virtual Machine for the device by clicking the “Z” button for the second time;
  • Virtualize the device by clicking the “Z” button for the third time.


No user intervention on the device is required for registration and virtualization process

After virtualization, the ST Nucleo L4R5 device is ready to be programmed and the Zerynth scripts uploaded. Just Select the virtualized device from the “Device Management Toolbar” and click the dedicated “uplink” button of Zerynth Studio .. warning:: Scripts uploading and serial console connection issues on St Nucleo devices have been reported. If the upload fails also with a correctly performed reset or if the device is not able to print on the console, disconnect the device from the USB port and plug it again on another USB socket.

If also this procedure fails, try to update the ST Nucleo firmware available at this link

Firmware Over the Air update (FOTA)

The Firmware Over the Air feature allows to update the device firmware at runtime. Zerynth FOTA in the ST Nucleo L4R5 device is available for bytecode and VM.

Flash Layout is shown in table below:

Start address Size Content
0x08000000 128Kb VM Slot 0
0x08020000 384kb Bytecode Slot 0
0x08080000 128kb VM Slot 1
0x080A0000 384kb Bytecode Slot 1


FOTA Record (small segment of memory where the current and desired state of the firmware is store) for the ST Nucleo L4R5 device is allocated in 16kb sector inside the VM Slot 0 at 0x08004000 address.