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Posts: 79 | Thanked: 719 times | Joined on May 2014 @ Buenos Aires, Argentina
#18
We have just released an update of the Hackerbus white paper, with quite a number of improvements (see below).

Link to the latest version of the document:

http://neo900.org/stuff/papers/hb.pdf

There are several significant changes. The highlights:

- Hackerbus now uses a dedicated USB High-Speed host port, with D+/D- directly accessible on the main Hackerbus connector (replacing two GPIOs). This reduces the risk of upsetting regular USB (OTG) operation.

- Access to USB OTG is still possible, but now uses spring-loaded contacts on the user circuit. This allows the mating contacts in the Neo900 to be simple PCB holes (instead of large header pins), reducing the risk of interference and signal degradation.

- More details on current limits and over-current protection.

- The optional (shared with GPIO) regulated power rail is now 2.7 V instead of 3.3 V. This simplifies the circuit (we already have a 2.7 V rail for various components, but may not have a 3.3 V rail), and most chips that operate with 3.3 V also accept 2.7 V.

- Appendix describing the board-to-board connection between BOB and LOWER. We need to consider this also for the Hackerbus design as it affects the placement of items and each imposes constraints on the other.

This specific version is at
http://neo900.org/stuff/papers/hb-20160211.pdf

The source can be found at
http://neo900.org/git/?p=misc;a=tree;f=hb

As always, comments are welcome.

- Werner
 

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