Spark Logic

1Bitsy connection guide

1Bitsy 1Bitsy v1.0d wiring guide with power, signal assignments, and bench checks.

1Bitsy v1.0d

74 contacts Current package

1BitSquared and Piotr Esden-Tempski · STM32F415RGT6 in LQFP-64 · 2.54 mm side and lower through-holes · Micro-USB B · 1.27 mm Cortex debug header.

Power the board over USB

Required

Use a 5 V USB host or supply with a Micro-B cable. The board already includes a series diode, 3.3 V regulator and decoupling. Use USB as the sole supply during these examples.

USB VBUS and ground feed the 1Bitsy. A voltmeter measures the onboard 3.3 V rail against ground.USB source1Bitsy v1.0d5 V VBUSP24-1 VBUSGNDP24-5 GND15/29 3V3DMM VDMM COM

Bench checks

  • Measure about 3.3 V at contact 15 or 29 relative to GND at contact 1 or 16.
  • Check that a peripheral draws only the current allowed by the fitted regulator and the USB source.

1Bitsy v1.0d schematic, power and USB blocks.

Connection scenarios

Enter the USB ROM bootloader

Disconnect the USB cable. Close the J1 solder jumper on the back with power off, keep PB2 low, and reconnect to the host using a data cable. The board couples the VBUS edge to BOOT0 through C15. Reopen J1 with power off to resume ordinary USB power-up.

C15 1 µF (on board) between USB power-up edge through closed J1 and BOOT0USB power-up edge through closed J1C15 1 µF (on board)BOOT0

Bench checks

  • Check the device enumerates as STM32 DFU (0483:DF11). A charge-only cable cannot enumerate.
  • If using the factory demo firmware, the documented User-button shortcut is another way to request DFU. This shortcut depends on the firmware in Flash.

1Bitsy v1.0d schematic, USB and MCU blocks; 1Bitsy Quickstart Guide.

1Bitsy v1.0d wiring map

Highlighted contacts are used in the required step or selected circuit. Select a contact to inspect it.

Component side · USB connector at the top
Lower expansion holes · inner row
Left to right, component side. Between VBAT and PB0.
Lower expansion holes · outer row
Left to right, component side. Between 3V3 and GND.
X3 Cortex debug header · upper row
Left to right, component side, with USB above X3.
X3 Cortex debug header · lower row
Left to right, component side.
P24 Micro-USB B
Connector pin order. Use a Micro-B data cable.
Auxiliary GPIO and switch
Contact identifiers. See the component-side drawing for locations.
Rear USB pads
Left to right, solder side, with USB at the top.
Rear debug pads
PCB pad identifiers. See the solder-side drawing for locations.
Rear boot jumper and RTC footprint
PCB pad identifiers. See the solder-side drawing for locations.
Selected pin details

P24-5 · USB_GND

Supply return · Ground

USB connector return, bonded to board ground.

1Bitsy v1.0d schematic

Electrical limits · Pin in the reference

Models and documents

Board revision v1.0d with STM32F415RGT6. Numbered contacts use the official board legend. IDs beginning with P, X, J or SW refer to PCB designators. The hardware archive also documents revisions v1.0a, v1.0b and v1.0c. Confirm the revision on the back before using this map.

1Bitsy v1.0d
STM32F415RGT6 · 1 MiB Flash · 192 KiB SRAM including 64 KiB CCM · 4 KiB backup SRAM.