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Nguyenvanhieu , 10-25-2016, 10:23 AM

Hi Robert,
I want to ask you something about importing reference schematic because i see that its not easy.Please,follow these question below :
1.What is your key word when you search gg for reference,e.g for IMX6 REX: reference schematic,reference design,development board... or something?BecauseI only find 1 reference schematic.
2.Why do you know reference sch trusted?
3.Do you do like that when design schematic? See on reference schematic,delete something you dont need,check and update reference schematic and follow design guide to complete preliminary schematic?
4.If pheripheral you need is not in reference schematic,will you design it by yourself?
Thank you so much.

robertferanec , 10-26-2016, 05:58 AM

@Nguyenvanhieu, these are very good questions.

1) You need to go on the chip manufacturer website and download everything from there. Very often this kind of documentation is behind Login and in restricted area.

2) I only trust reference schematics with working boards.

3) If you do not need something, you can delete it (but you have to double check if you can leave it unconnected) or leave it unfitted.

4) Yes. But for ARM boards it is important to do some home work before you decide on the final chip / solution. Let's say, you need a HDMI input for iMX6. If your reference board (SabreSD) doesn't have the peripheral then:

- have a look if the chip manfacturer (NXP) doesnt have reference boards for the same chip (iMX6) but with the peripheral you need (e.g. check Sabre AI). If not:
- have a look if boards with same chip (iMX6) from other manufacturers (e.g. Wandboard) do not use the peripheral. If not:
- have a look what chips you could use (for HDMI input) and search if someone has connected something (google for iMX6 + chip names). If not:
- you need to buy development board of the chip (HDMI input development board), wire it up to your reference board and try to make it work

If you need to connect a new peripheral, usually you get reference schematic. The circuit / connection is not a problem. Problem is software support (writing drivers may be hard and time consuming) and communication support (many times the same protocol used for communication between chips has a lot of variants and sometimes chips don't want to talk together correctly - even if they should).

robertferanec , 10-27-2016, 06:43 AM

Theoretically, you do not have to understand software, practically it's useful to understand it. If you know how software is working on the board, you will understand better how to design hardware which will be easy to make work in the software. To write some drivers is very difficult (especially if you do not have a driver expert in your company .... ).