General > General Technical Chat
are drawing normal schematics a dying art?
Terry Bites:
See my post: Can anyone still use a pencil?
https://www.eevblog.com/forum/projects/can-anyone-still-use-a-pencil/msg3810782/#msg3810782
It must be a shotage of envelope backs an fag packets.
VK3DRB:
--- Quote from: Berni on November 18, 2021, 07:41:29 am ---...The one annoying thing to clearly show are UART lines. There is no strictly defined master/slave since both nodes are symmetrical while you do have to cross over the RX and TX lines for it to work. So naming the nets becomes tricky. This is where the Altium direction arrows on the schematic sheet ports help, but sometimes i have UART going into a connector. I started drawing extra direction arrows there too in order to show what way the data is flowing.
--- End quote ---
The TX and RX pin on a chip's schematic symbol should always be in reference to that chip. The TX and RX lines on a board connector should be in reference to the board. Some people name the net labels with the reference in the name eg: "MCU-TX" meaning it is a TX from the MCU chip.
In my opinion, a very good idea is to use direction arrows in the device symbols. With Altium, for example, a microcontroller's symbol will have the TX line shown as an output and the RX line the receiving chip as an input. This makes it so much easier to read - no confusion and no ambiguity! The library symbol stays the same, but the instance on the schematic is modified showing the respective directions. The only risk here is if you carelessly do a symbol update from the library, it can be overwritten.
penfold:
The RX and TX ‘issue’ is one reason I quite like keeping the number of ‘functions’ per sheet lower, because naturally in the hierarchy it gives an additional planning stage to define signal directions, altium makes it clear enough if there’s any violations that aren’t visible. So along with sensible naming, pin directions and annotations (fewer components… more room to annotate!) it makes everything easy to review, rather than “oh that’s not right, what was it meant to be” it’s “is what I intended to do correct and does it match what I drew”, doesn’t necessarily eliminate page turning, but it gives page turning a very defined objective to prove or disprove a single statement
Berni:
--- Quote from: VK3DRB on November 25, 2021, 12:21:22 am ---The TX and RX pin on a chip's schematic symbol should always be in reference to that chip. The TX and RX lines on a board connector should be in reference to the board. Some people name the net labels with the reference in the name eg: "MCU-TX" meaning it is a TX from the MCU chip.
--- End quote ---
Yes in a lot of cases it is possible to have a sensible "Master" on that UART bus. In those causes i prefer to name the lines as being TX from the MCUs point of view. For example a MCU talking to a GPS receiver or Bluetooth module or something.
But sometimes things become tricky. I had cases where two MCUs talk to each other on the same board (It was some small MCU doing time critical stuff) or you have two MCUs on separate boards talking to each other over a connector or cable. For clarity you want to maintain naming of the connector pins on both sides so that its easy to follow the signal from schematic to schematic. Yet both are a MCU talking UART to some pins on a connector.
So the directional schematic ports in Altium are really nice for making this more clear. Where i have a UART bus just going into a connector (or something else without direction) i manually add some graphical arrows to it, so its clear what direction its flowing just by looking at the connector.
But this is just 1 small part of it. There are plenty worse ways to make schematics into a confusing mess.
AlienRelics:
--- Quote from: Miyuki on November 16, 2021, 08:37:39 am ---Oh, thanks, I did not know it is called Fritzing
--- End quote ---
No, it is called a pictorial diagram. This particular program is called Fritzing.
--- Quote ---It looks like a great way to explain to non-technical people where to put what wire :-+
It is a totally different thing that schematics
--- End quote ---
Very true, and sad. I blame Make: Magazine for destroying the art of drawing clear, cogent schematics. They have these bastardized half-schematic, half-pictorial diagrams with an IC being shown as a block with 14 pins and no labels. It requires you to break out the datasheets and redraw the circuit to figure out what is going on.
I guess the question is, do you just want to assemble other people's projects? Or learn how they work so you can change them and even design your own?
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version