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

Connect a Serial Wire Debug probe

With USB powering the board and target-power output disabled on the probe, connect a keyed 10-position Cortex cable to X3. For individual wiring, match each signal to the probe’s target connector and use short leads.

1Bitsy X3 and probe wiring for Serial Wire Debug. Reset and trace are optional.1Bitsy X3Debug probe1 VTrefVTref input2 SWDIOSWDIO4 SWCLKSWCLK3/5 GNDGND9 GNDDetectGNDDetect10 NRSTnRESET (opt.)6 SWOSWO (opt.)

Bench checks

  • Confirm the cable orientation against pin 1 and the connector key.
  • Read the target ID, then halt or reset the core from the debugger. If the firmware prevents an attach, use the probe’s connect-under-reset mode with NRST connected.

1Bitsy v1.0d schematic, X3; 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

SW1-2 · PC1

Input · Inputs

User pushbutton node. The 10 kΩ pull-up reads HIGH when released and LOW when pressed. PC1 also supports ADC channel 11.

1Bitsy v1.0d schematic; ST DS8597 Rev 9, Tables 7 and 9

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.