STM32F103 BPSK pulse generator connection guide

• USB power input
  • USB host VBUS
  • VBUS (H4-1)
• USB return
  • USB host ground
  • GND (H4-5)
• Board logic rail
  • 3V3 (H3-1)
  • 3.3 V measurement point

Bench checks

• Identify the USB power input and ground in the board schematic.
• Measure roughly 3.3 V between the board logic rail and ground. Check for a short or wrong connector if the rail is low.

STM32F103C8T6 Blue Pill connector map

Compare the two phase outputs

• Primary output
  • A8 (H2-16)
  • Oscilloscope CH1
• Complementary output
  • B13 (H2-19)
  • Oscilloscope CH2
• Return
  • G (H2-2)
  • Both probe ground clips

Bench checks

• Measure a 25 µs carrier period in the middle of the burst.
• Trigger on the start of a burst. Verify that the outputs are complementary and that the programmed phase reversal occurs at the expected sample.

Original STM32F103 BPSK project, initial timing and GPIO test.

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

This guide covers the documented transmitter-side timing experiment on the bench. The archived discussion does not establish a complete modem or a receiver implementation.

STM32F103C8T6 Blue Pill

The documented blue PCB has two 20-contact headers, SWD and Micro USB. Its PC13 user LED is active low. The USB D+ pull-up varies across production boards.

• Original Spark Logic project discussion· Author’s hardware, firmware and bench notes.
• STMicroelectronics RM0008 reference manual· Timer modes, DMA request mapping and USB registers.
• STM32-base · STM32F103C8T6 Blue Pill· Board identification, connector numbering and documented net destinations.
• STMicroelectronics MCU datasheet· MCU electrical specifications and package pin functions.
• STM32F103C8T6 Blue Pill schematic· PCB power, debug, connector and peripheral wiring.