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1TE DIN Rail eBus to USB Type-C Adapter

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jkyprian/ebus2usb

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ebus2usb - 1TE DIN Rail eBUS to USB Type-C Interface

eBUS is a serial 2-wire serial data-bus, often used in heating, solar energy, and other building automation systems. This project provides an interface to access an eBUS via USB. It uses a series transistor regulator circuit with a low IZT zener diode to extract the operating voltage from the eBUS, an ADuM1201 for the galvanic isolation, and a STM32 microcontroller for the UART to USB conversion. Power consumption on the eBUS side is between 475uA (eBUS low/8V) and 750uA (eBUS idle high/24V), making the interface qualify as a class 0 device with respect to the eBUS specification. It has been designed to fit into an CNMB/1/2 1TE DIN rail enclosure by CAMDENBOSS. The interface is intended to be used with ebusd. Note that the firmware is currently just a proof-of-concept and only implements a basic uart to USB bridge. Support for the ebusd enhanced protocol is planned for the near future.

Images

Schematic

Schematic

PCB Layout

PCB Layout

When ordering at JLCPCB, remove the mouse bites and cut the boards yourself. Otherwise JLCPCB will charge you for two designs.

BOM

Designator Footprint Quantity Value LCSC Part #
C1, C2, C7 C0805 3 10u C15850
C10, C3, C4, C5, C6, C8, C9 C0603 7 100n C14663
C11, C12 C0805 2 1u C28323
D1, D2, D4 SOT-23-3 3 BAV99 C2500
D3 SOD-123 1 5V6, Onsemi MMSZ4690* C152307
D5 SOD-123 1 24V/1W, KDZVTR24B, MM1W24 C209605, C438336
D6 SOD-123 1 7V5/1W, KDZVTR7.5B, MM1W7V5 C209594, C382950
D7 LED_0603 1 LED C72043
D8, D9, D10 D3.0mm 3 3mm LED CHANZON 3mm diffused LED
J1 MSTBA_2,5_2-G-5,08 1 MSTBA 2,5/2-G-5,08 C3697
J2, J6 Molex_PicoBlade_53047-0210 2 Molex 53047-0210 C114130
J3, J7 Molex_PicoBlade_53047-0410 2 Molex 53047-0410 C504989
J4 TC2030-NL 1 Tag-Connect 6-Pin "No Legs" TC2030-NL Plug-of-Nails TC2030-CTX-NL-STDC14
J5 HRO_TYPE-C-31-M-12 1 HRO TYPE-C-31-M-12 C165948
J8 PinHeader_1x02_P1.27mm 1 Harwin M50-3530242 C2881948
Q1, Q2 SOT-23-3 2 BC817-40, S9013J3 C52801, C6749
R1, R2, R3 R0603 3 100K C25803
R10 R0603 1 47K C25819
R12, R13 R0603 2 5K1 C23186
R14 R0805 1 100K C149504
R15, R16 R0805 2 15K C17475
R4 R0603 1 4K7 C23162
R5 R0603 1 300K C23024
R6 R0603 1 51K C23196
R7 R0603 1 2M C22976
R8 R0603 1 10K C25804
R9 R0603 1 0R C21189
U1 SO08 1 AZV3002, TSX3702 C5123396, C2970396
U2 SO08 1 ADuM1201, π122U31 C9669, C471590
U5 SOT-23-6L 1 SRV05-4 C85364
U6 SOT-23-3 1 XC6206P332MR C5446
U7 LQFP-32 1 STM32L412KBT6, STM32F042K6T6 C529438, C69216

* Low IZT of 50uA is required. Other manufacturers than Onsemi may not qualify. For example, MMSZ4690 from Jiangsu Changjing Elec. Tech. is not recommened.