HydraBus v1.0 Rev1.4 Schematic/Board Layout are available on github, everything is done with the amazing KiCad PCB

HydraBus: Hardware license CC BY-NC 4.0 (for commercial license contact info@hydrabus.com)

For more details on the hardware see also http://hydrabus.com/hydrabus-1-0-specifications

Revision 1.4 (vs Rev 1.3)

• The BOM has been optimized to find/buy most of the parts on lcsc.com
• HydraBus v1 Rev1.4 is fully designed under KiCad 5.1.5-2 (Latest official stable release), before it was designed with Eagle 6.x
• 8MHz Crystal Y1 has been replaced by a SMD part (Yangxing Tech X50328MSB2GI) on top side of the PCB with better performances
  • Frequency Tolerance @25°C X50328MSB2GI +/-10ppm vs FOXSLF/080-20 +/-30ppm.
  • Operating Temperature X50328MSB2GI -40°C / +85°C vs FOXSLF/080-20 -20°C / +70°C.
• Capacitors C1 & C2 for the 8MHz Crystal are changed to 18pF (before it was 27pF) to prevent some USB issues on some board which does not work correctly with STM32F405 USB DFU (embedded in ROM).
• Decoupling capacitors (100nF replaced by 220nF, 1uF replaced by 2.2uF) are modified to use less references with higher value which also reduce the noise.
• microSD connector part replaced by compatible part HOAUC HYC77-TF09-200UBTN/BOOT DFU and RESET switch replaced by compatible part HYP (Hongyuan Precision) 1TS002G-2700-3500-CTTo summarize there is no any functional change between HydraBus v1 Rev1.4 and previous versions.

For more details see:

• https://github.com/hydrabus/hydrabus/tree/master/hardware/HydraBus_1_0_Rev1_4_Kicad

HydraBus v1.0 Rev1.4 is now available for purchase:

• https://hydrabus.com/buy-online