{ "family": "Core", "name": "ST.L4.1", "rev": "a", "tile_id": 1, "json_version": "0.34", "updated_at": "2026-06-02T12:36:00.552Z", "headline": "USB-programmable Cortex-M4", "description": "The USB-programmable Core.ST.L4.1 (formerly Core.U.1) is based on the 80-MHz 32-bit Cortex-M4 STM32L422 with 128KB flash, 40KB SRAM, and a CoreMark score of 273.55. The exposed pads provide a user-configurable combination of two fast-mode-plus I2C ports, one SPI port, three 12-bit ADCs, multiple timers, USART, an onboard comparator, and capacitive-touch input. A programmable onboard LED provides a convenient status indicator. If more I/O is needed, consider the larger Core.ST.L4.2 in a T48-22 package.", "application_notes": [ { "details": "When the chip is blank, it will default into the bootloader when connected over USB. Once there is code in the program space, you need to hold the BOOT0 pin low during reset (either power-on or via the NRST pin) to enter the bootloader.", "heading": "Bootloading" }, { "details": "The onboard LED is connected to PA8 in an active-high configuration.", "heading": "LED" } ], "package": { "pads": 12, "type": "T44", "size_x": 4000, "size_y": 4000, "size_z": 0 }, "power": [ { "max": 3.6, "min": 1.71, "type": "system", "notes": "minimum of 3.0V for USB communications", "gnd_pad": [ "1" ], "function": "", "direction": "input", "is_required": true, "max_current": "", "positive_pad": [ "10" ] } ], "components": [ { "url": "https://www.st.com/en/microcontrollers-microprocessors/stm32l422tb.html", "part": "STM32L422TB", "datasheet": "https://mosaic-component-datasheets.s3.eu-north-1.amazonaws.com/1/ST_Microelectronics-STM32L422TB.pdf", "manufacturer": "ST Microelectronics" } ], "pads": [ { "pad": "1", "geometry": { "size_x": 1000, "size_y": 400, "center_x": -1500, "center_y": 1600 }, "functions": [ { "type": "power", "function": "GND", "direction": "" } ] }, { "pad": "2", "geometry": { "size_x": 800, "size_y": 400, "center_x": -1600, "center_y": 800 }, "functions": [ { "note": "", "type": "digital", "function": "A7", "direction": "bidirectional", "is_default": true }, { "af": 4, "note": "", "type": "digital", "function": "I2C3.CLK", "direction": "bidirectional", "interface": "I2C3" }, { "af": 5, "note": "", "type": "digital", "function": "SPI1.MOSI", "direction": "bidirectional", "interface": "SPI1" }, { "note": "", "type": "analog", "function": "ADC12", "direction": "input" }, { "af": 1, "note": "", "type": "timer", "function": "TIM1.1N", "direction": "output" } ] }, { "pad": "3", "geometry": { "size_x": 800, "size_y": 400, "center_x": -1600, "center_y": 0 }, "functions": [ { "note": "", "type": "digital", "function": "A1", "direction": "bidirectional", "is_default": true }, { "af": 4, "note": "optional SMBus alert", "type": "digital", "function": "I2C1.SMBA", "direction": "", "interface": "I2C1" }, { "af": 5, "note": "", "type": "digital", "function": "SPI1.CLK", "direction": "bidirectional", "interface": "SPI1" }, { "note": "", "type": "analog", "function": "ADC6", "direction": "input" }, { "af": 1, "note": "", "type": "timer", "function": "TIM2.2", "direction": "output" }, { "af": 14, "note": "", "type": "timer", "function": "TIM15.1N", "direction": "output" }, { "note": "", "type": "other", "function": "COMP1.+", "direction": "input" } ] }, { "pad": "4", "geometry": { "size_x": 800, "size_y": 400, "center_x": -1600, "center_y": -800 }, "functions": [ { "type": "digital", "function": "B6", "direction": "bidirectional", "is_default": true }, { "af": 4, "type": "digital", "function": "I2C1.CLK", "direction": "bidirectional", "interface": "I2C1" }, { "af": 14, "type": "timer", "function": "TIM16.1N", "direction": "output" }, { "af": 1, "note": "external trigger", "type": "timer", "function": "LPTIM1.ETR", "direction": "input" }, { "af": 7, "type": "digital", "function": "USART1.TX", "direction": "output", "interface": "USART1" }, { "af": 9, "note": "", "type": "other", "function": "G2.IO3", "direction": "" } ] }, { "pad": "5", "geometry": { "size_x": 800, "size_y": 400, "center_x": -1600, "center_y": -1600 }, "functions": [ { "type": "digital", "function": "B7", "direction": "bidirectional", "is_default": true }, { "af": 4, "type": "digital", "function": "I2C1.DAT", "direction": "bidirectional", "interface": "I2C1" }, { "af": 1, "type": "timer", "function": "LPTIM1.2", "direction": "output" }, { "af": 7, "type": "digital", "function": "USART1.RX", "direction": "input", "interface": "USART1" }, { "af": 9, "note": "", "type": "other", "function": "G2.IO4", "direction": "" } ] }, { "pad": "6", "geometry": { "size_x": 800, "size_y": 400, "center_x": 1600, "center_y": -1600 }, "functions": [ { "note": "", "type": "digital", "function": "A12", "direction": "bidirectional", "is_default": true }, { "af": 5, "type": "digital", "function": "SPI1.MOSI", "direction": "output", "interface": "SPI1" }, { "af": 1, "note": "external trigger", "type": "timer", "function": "TIM1.ETR", "direction": "input" }, { "af": 7, "note": "RS232 ready-to-send / RS485 driver-enable", "type": "digital", "function": "USART1.RTS_DE", "direction": "bidirectional", "interface": "USART1" }, { "af": 10, "type": "digital", "function": "USB.DP", "direction": "bidirectional", "interface": "USB" } ] }, { "pad": "7", "geometry": { "size_x": 800, "size_y": 400, "center_x": 1600, "center_y": -800 }, "functions": [ { "note": "", "type": "digital", "function": "A11", "direction": "bidirectional", "is_default": true }, { "af": 5, "type": "digital", "function": "SPI1.MISO", "direction": "output", "interface": "SPI1" }, { "af": 1, "type": "timer", "function": "TIM1.4", "direction": "output" }, { "af": 2, "note": "break input to disable PWM output", "type": "timer", "function": "TIM1.BKIN2", "direction": "input" }, { "af": 12, "note": "break input to disable PWM output based on COMP1 output", "type": "timer", "function": "TIM1.BKIN2_COMP1", "direction": "input" }, { "af": 7, "note": "RS232 clear-to-send", "type": "digital", "function": "USART1.CTS", "direction": "bidirectional", "interface": "USART1" }, { "af": 6, "type": "other", "function": "COMP1.OUT", "direction": "output" }, { "af": 10, "type": "digital", "function": "USB.DM", "direction": "bidirectional", "interface": "USB" } ] }, { "pad": "8", "geometry": { "size_x": 800, "size_y": 400, "center_x": 1600, "center_y": 0 }, "functions": [ { "note": "", "type": "digital", "function": "B4", "direction": "bidirectional", "is_default": true }, { "af": 4, "type": "digital", "function": "I2C3.DAT", "direction": "bidirectional", "interface": "I2C3" }, { "af": 5, "type": "digital", "function": "SPI1.MISO", "direction": "output", "interface": "SPI1" }, { "af": 7, "note": "RS232 clear-to-send", "type": "digital", "function": "USART1.CTS", "direction": "bidirectional", "interface": "USART1" }, { "af": 9, "note": "", "type": "other", "function": "G2.IO1", "direction": "" } ] }, { "pad": "9", "geometry": { "size_x": 800, "size_y": 400, "center_x": 1600, "center_y": 800 }, "functions": [ { "note": "", "type": "digital", "function": "A4", "direction": "bidirectional", "is_default": true }, { "af": 5, "type": "digital", "function": "SPI1.CS", "direction": "bidirectional", "interface": "SPI1" }, { "af": 14, "note": "break input to disable PWM output", "type": "timer", "function": "LPTIM2.OUT", "direction": "output" }, { "type": "other", "function": "COMP1.-", "direction": "input" } ] }, { "pad": "10", "geometry": { "size_x": 800, "size_y": 400, "center_x": 1600, "center_y": 1600 }, "functions": [ { "note": "1.71-3.6V (>=3.3V for USB)", "type": "power", "function": "V+", "direction": "input" } ] }, { "pad": "11", "geometry": { "size_x": 400, "size_y": 800, "center_x": 400, "center_y": 1600 }, "functions": [ { "note": "internal pull-down defaults to run mode, hold high during reset to enter bootloader", "type": "system", "function": "BOOT0", "direction": "input", "is_default": true }, { "type": "digital", "function": "H3", "direction": "bidirectional" } ] }, { "pad": "12", "geometry": { "size_x": 400, "size_y": 800, "center_x": -400, "center_y": 1600 }, "functions": [ { "note": "active-low reset with internal pull-up", "type": "system", "function": "NRST", "direction": "input" } ] } ], "interfaces": [ { "name": "I2C1", "type": "I2C", "parameters": { "modes": [ "master, slave" ], "addresses": [ { "address": "programmable" } ], "address_bits": [ 7 ], "max_clock_speed": "1MHz" }, "pad_assignments": [ { "pad": "3", "role": "bus", "function": "I2C1.SMBA" }, { "pad": "4", "role": "bus", "function": "I2C1.CLK", "is_required": true }, { "pad": "5", "role": "bus", "function": "I2C1.DAT", "is_required": true } ], "mutually_exclusive": [ "USART1" ] }, { "name": "I2C3", "type": "I2C", "parameters": { "modes": [ "master, slave" ], "addresses": [ { "address": "programmable" } ], "address_bits": [ 7 ], "max_clock_speed": "1MHz" }, "pad_assignments": [ { "pad": "2", "role": "bus", "function": "I2C3.CLK", "is_required": true }, { "pad": "8", "role": "bus", "function": "I2C3.DAT", "is_required": true } ] }, { "name": "SPI1", "type": "SPI", "parameters": { "modes": [ "master, slave" ], "max_clock_speed": "40Mhz (master), 20MHz (slave)" }, "pad_assignments": [ { "pad": "3", "role": "bus", "function": "SPI1.CLK", "is_required": true }, { "pad": "7", "role": "bus", "function": "SPI1.MISO" }, { "pad": "8", "role": "bus", "function": "SPI1.MISO" }, { "pad": "9", "role": "other", "function": "SPI1.CS" }, { "pad": "2", "role": "bus", "function": "SPI1.MOSI" }, { "pad": "6", "role": "bus", "function": "SPI1.MOSI" } ] }, { "name": "USB", "type": "USB", "parameters": { "modes": [] }, "pad_assignments": [ { "pad": "6", "role": "bus", "function": "USB.DP", "is_required": true }, { "pad": "7", "role": "bus", "function": "USB.DM", "is_required": true } ] }, { "name": "USART1", "type": "USART", "parameters": { "modes": [] }, "pad_assignments": [ { "pad": "4", "role": "bus", "function": "USART1.TX", "is_required": true }, { "pad": "5", "role": "bus", "function": "USART1.RX", "is_required": true }, { "pad": "6", "role": "bus", "function": "USART1.RTS_DE" }, { "pad": "7", "role": "bus", "function": "USART1.CTS" }, { "pad": "8", "role": "bus", "function": "USART1.CTS" } ], "mutually_exclusive": [ "I2C1" ] } ], "config": { "gpio": { "kind": "padconfig", "group": "Pinmux", "label": "GPIO pad configuration", "perPad": { "fields": { "exti": { "kind": "select", "when": { "direction": "in" }, "default": "none", "options": [ { "value": "none" }, { "value": "rising" }, { "value": "falling" }, { "value": "both" } ] }, "pull": { "kind": "select", "default": "none", "options": [ { "value": "none" }, { "value": "up" }, { "value": "down" } ] }, "speed": { "kind": "select", "default": "medium", "options": [ { "value": "low" }, { "value": "medium" }, { "value": "high" }, { "value": "very-high" } ] }, "direction": { "kind": "select", "default": "in", "options": [ { "value": "in" }, { "value": "out" } ] }, "output_default": { "kind": "select", "when": { "direction": "out" }, "default": "low", "options": [ { "value": "low" }, { "value": "high" } ] } } }, "appliesTo": { "selector": "pads.", "whereValueDerived": { "role": "gpio" } } }, "pads": { "kind": "padmux", "group": "Pinmux", "label": "Pad function assignments", "perPad": { "2": { "label": "Pad 2", "default": "A7", "options": [ { "value": "A7", "derived": { "role": "gpio" } }, { "af": 4, "value": "I2C3.CLK", "interface": "I2C3" }, { "af": 5, "value": "SPI1.MOSI", "interface": "SPI1" }, { "value": "ADC12", "derived": { "role": "analog" } }, { "af": 1, "value": "TIM1.1N", "derived": { "role": "timer-output" } } ] }, "3": { "label": "Pad 3", "default": "A1", "options": [ { "value": "A1", "derived": { "role": "gpio" } }, { "af": 4, "value": "I2C1.SMBA", "interface": "I2C1" }, { "af": 5, "value": "SPI1.CLK", "interface": "SPI1" }, { "value": "ADC6", "derived": { "role": "analog" } }, { "af": 1, "value": "TIM2.2", "derived": { "role": "timer-output" } }, { "af": 14, "value": "TIM15.1N", "derived": { "role": "timer-output" } }, { "value": "COMP1.+" } ] }, "4": { "label": "Pad 4", "default": "B6", "options": [ { "value": "B6", "derived": { "role": "gpio" } }, { "af": 4, "value": "I2C1.CLK", "interface": "I2C1" }, { "af": 14, "value": "TIM16.1N", "derived": { "role": "timer-output" } }, { "af": 1, "value": "LPTIM1.ETR", "derived": { "role": "timer-input" } }, { "af": 7, "value": "USART1.TX", "interface": "USART1" }, { "af": 9, "value": "G2.IO3" } ] }, "5": { "label": "Pad 5", "default": "B7", "options": [ { "value": "B7", "derived": { "role": "gpio" } }, { "af": 4, "value": "I2C1.DAT", "interface": "I2C1" }, { "af": 1, "value": "LPTIM1.2", "derived": { "role": "timer-output" } }, { "af": 7, "value": "USART1.RX", "interface": "USART1" }, { "af": 9, "value": "G2.IO4" } ] }, "6": { "label": "Pad 6", "default": "A12", "options": [ { "value": "A12", "derived": { "role": "gpio" } }, { "af": 5, "value": "SPI1.MOSI", "interface": "SPI1" }, { "af": 1, "value": "TIM1.ETR", "derived": { "role": "timer-input" } }, { "af": 7, "value": "USART1.RTS_DE", "interface": "USART1" }, { "af": 10, "value": "USB.DP", "interface": "USB" } ] }, "7": { "label": "Pad 7", "default": "A11", "options": [ { "value": "A11", "derived": { "role": "gpio" } }, { "af": 5, "value": "SPI1.MISO", "interface": "SPI1" }, { "af": 1, "value": "TIM1.4", "derived": { "role": "timer-output" } }, { "af": 2, "value": "TIM1.BKIN2", "derived": { "role": "timer-input" } }, { "af": 12, "value": "TIM1.BKIN2_COMP1", "derived": { "role": "timer-output" } }, { "af": 7, "value": "USART1.CTS", "interface": "USART1" }, { "af": 6, "value": "COMP1.OUT" }, { "af": 10, "value": "USB.DM", "interface": "USB" } ] }, "8": { "label": "Pad 8", "default": "B4", "options": [ { "value": "B4", "derived": { "role": "gpio" } }, { "af": 4, "value": "I2C3.DAT", "interface": "I2C3" }, { "af": 5, "value": "SPI1.MISO", "interface": "SPI1" }, { "af": 7, "value": "USART1.CTS", "interface": "USART1" }, { "af": 9, "value": "G2.IO1" } ] }, "9": { "label": "Pad 9", "default": "A4", "options": [ { "value": "A4", "derived": { "role": "gpio" } }, { "af": 5, "value": "SPI1.CS", "interface": "SPI1" }, { "af": 14, "value": "LPTIM2.OUT", "derived": { "role": "timer-output" } }, { "value": "COMP1.-" } ] }, "11": { "label": "Pad 11", "default": "BOOT0", "options": [ { "value": "BOOT0", "derived": { "role": "system" } }, { "value": "H3", "derived": { "role": "gpio" } } ] } }, "derives": "catalog.pads" }, "clock": { "kind": "select", "group": "Clock", "label": "Clock configuration", "default": "medium", "options": [ { "label": "Low (8MHz, MSI)", "value": "low", "firmware_contract": [ { "type": "clock", "source": "msi", "sysclk_mhz": 8 } ] }, { "label": "Medium (16MHz, MSI)", "value": "medium", "firmware_contract": [ { "type": "clock", "source": "msi", "sysclk_mhz": 16 } ] }, { "label": "High (48MHz, MSI)", "value": "high", "firmware_contract": [ { "type": "clock", "source": "msi", "sysclk_mhz": 48 } ] }, { "label": "Max (80MHz, HSI16 + PLL)", "value": "max", "firmware_contract": [ { "pll": true, "type": "clock", "source": "hsi16", "sysclk_mhz": 80 } ] } ] }, "bootloader": { "kind": "multiselect", "group": "Bootloader", "label": "Programming methods", "default": [], "options": [ { "value": "USB_DFU" }, { "value": "USART1" }, { "value": "USART2" }, { "value": "USART3" }, { "value": "I2C1" }, { "value": "I2C3" }, { "value": "SPI1" } ] }, "interfaces": { "kind": "instances", "group": "Interfaces", "label": "Interfaces", "derives": "catalog.interfaces", "defaults": { "role": { "kind": "select", "when": { "enabled": true }, "default": "master", "options": [ { "value": "master" }, { "value": "slave" } ] }, "speed": { "max": 1000000, "min": 100000, "kind": "number", "unit": "Hz", "when": { "enabled": true }, "default": 400000 }, "enabled": { "kind": "boolean", "default": false } }, "perInstance": { "USB": { "fields": { "role": { "kind": "select", "when": { "enabled": true }, "default": "device", "options": [ { "value": "host" }, { "value": "device" } ] }, "deviceClass": { "kind": "select", "when": { "enabled": true }, "default": "cdc", "options": [ { "value": "none" }, { "value": "cdc" }, { "value": "hid" }, { "value": "dfu" }, { "value": "msc" } ] } }, "netlist": { "when": { "enabled": true }, "buses": [ { "bus": "usb", "tag": "USB.bus", "signalsFrom": "interfaces.USB.pad_assignments" } ] }, "requires": { "predicates": { "pads.6": "USB.DP", "pads.7": "USB.DM" } }, "firmware_contract": { "entries": [ { "via": "register", "type": "register", "value": 1, "register": "RCC.CLK_EN.USB" } ] } }, "I2C1": { "fields": { "address": { "max": 119, "min": 8, "kind": "number", "unit": "7-bit", "when": { "role": "slave" }, "default": 66 } }, "netlist": { "when": { "enabled": true }, "buses": [ { "bus": "i2c", "tag": "I2C1.bus", "signalsFrom": "interfaces.I2C1.pad_assignments" } ] }, "requires": { "predicates": { "pads.4": "I2C1.CLK", "pads.5": "I2C1.DAT" } }, "firmware_contract": { "entries": [ { "via": "register", "type": "register", "value": 1, "register": "RCC.CLK_EN.I2C1" } ] } }, "I2C3": { "fields": { "address": { "max": 119, "min": 8, "kind": "number", "unit": "7-bit", "when": { "role": "slave" }, "default": 66 } }, "netlist": { "when": { "enabled": true }, "buses": [ { "bus": "i2c", "tag": "I2C3.bus", "signalsFrom": "interfaces.I2C3.pad_assignments" } ] }, "requires": { "predicates": { "pads.2": "I2C3.CLK", "pads.8": "I2C3.DAT" } }, "firmware_contract": { "entries": [ { "via": "register", "type": "register", "value": 1, "register": "RCC.CLK_EN.I2C3" } ] } }, "SPI1": { "netlist": { "when": { "enabled": true }, "buses": [ { "bus": "spi", "tag": "SPI1.bus", "signalsFrom": "interfaces.SPI1.pad_assignments" } ] }, "requires": { "predicates": { "pads.3": "SPI1.CLK" } }, "firmware_contract": { "entries": [ { "via": "register", "type": "register", "value": 1, "register": "RCC.CLK_EN.SPI1" } ] } }, "USART1": { "netlist": { "when": { "enabled": true }, "buses": [ { "bus": "uart", "tag": "USART1.bus", "signalsFrom": "interfaces.USART1.pad_assignments" } ] }, "requires": { "predicates": { "pads.4": "USART1.TX", "pads.5": "USART1.RX" } }, "firmware_contract": { "entries": [ { "via": "register", "type": "register", "value": 1, "register": "RCC.CLK_EN.USART1" } ] } } } } }, "features": { "led": { "kind": "led", "color": "red", "label": "Status LED", "control": { "pin": "PA8", "via": "gpio", "polarity": "active-high" }, "center_x": 1650, "center_y": 350, "rotation": 90 }, "clock": { "kind": "clock", "sources": [ { "type": "hsi16", "description": "16MHz internal RC", "frequency_mhz": 16 }, { "type": "msi", "description": "Multi-speed internal RC (100kHz-48MHz)", "frequency_mhz": 4 }, { "type": "hsi48", "description": "48MHz internal RC (USB)", "frequency_mhz": 48 } ], "boot_source": "hsi16" } } }