Sending Boards off for Fabrication

Sending Boards off for Fabrication#

I have had a busy few days and have finally got around to sending some more boards off for fabrication. This time, the boards are the RS485 non-isolated board and the revised Digital I/O Expander Board.

The RS485 board has had a few tweaks. I have reintroduced 22 ohm series resistors on the A and B lines, with associated solder jumpers so that they can be bypassed if necessary. Apart from that, the design is largely the same as the previous version, except that I have moved to smaller screw terminals than last time.

The non-isolated RS485 board is aimed at bench, cabinet, and room-scale deployments, where a simple common-ground RS485 interface is suitable. The isolated version will be aimed more at larger multi-room deployments or industrial installations, where electrical isolation is required or strongly preferred.

The Digital I/O Expander Board has been more heavily revised. After thinking through the purpose of the board again, I decided to expand the amount of I/O available. The new version now has 16 logic-level inputs and 16 logic-level outputs, all intended for 3.3 V logic-level signalling.

That should hopefully be enough for most input control applications. At the very least, this board should give me more options when I start running out of pins on a microcontroller or development board.

I may also investigate an I2C bus version of the board in future, especially if I find that some applications need more I/O than makes sense to handle through the current approach.

I also received the NUCLEO-G071RB and NUCLEO-G070RB boards that I ordered previously. These should allow me to start experimenting properly with USB-C Power Delivery and eventually work towards a USB-C PD test and negotiation board.

That project is further down the pipeline, but it is useful to have the core development boards in hand. The X-NUCLEO-DRP1M1 daughterboard should come in handy for this work, as it gives me a ready-made platform for exploring USB-C Power Delivery behaviour before designing my own board.

I also received the NUCLEO-G070RB board so that I can investigate the capabilities of the lower-cost STM32G0 variant. It will be interesting to see where the lower-cost device is sufficient, and where the additional USB-C/PD features of the G071 make it the better fit.

For now, the main focus is getting the RS485 and Digital I/O boards fabricated, assembled, and tested. Once validated, they should become useful building blocks for control panels, industrial interfaces, test fixtures, and small embedded systems.

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