1. Basics of the `ato` language¶

ato is a domain specific language (DSL) for describing electronic circuit boards.

It's heavily inspired by, and attempts to largely follow the syntax of Python 🐍 for consistency and familiarity.

Basic types¶

The most basic types in ato are a module and an interface.

A signal is a special built-in type of interface that represents a single electrical interface.

A component is a subclass of a module that expects to represent a single physical component.

You can also define you own types, in a similar way to define a class in Python. Like classes in most modern languages, we can subclass and inherit from blocks.

module SomeModule:
    signal some_signal
    signal gnd
    some_variable = "some value"

module SubclassedModule from SomeModule:
    # inherits all the signals and variables from SomeModule
    # we don't need to declare the signals again,
    # but we will replace the value of some_variable
    some_variable = "some other value"

module Test:
    signal gnd
    # creates an instance of the SubclassedModule
    subclassed_module = new SubclassedModule
    # connects the some_signal of the SubclassedModule to the gnd of Test
    subclassed_module.gnd ~ gnd

Info

You can subclass a module as a component, but not the other way around. A component is expected to represent a specific component.

Configuring blocks¶

Configuration of a module or interface is done by assigning to it's attributes.

some_instance.value = 100ohm +/- 10%

Unlike Python, you don't need to state self. and instead any assignments you make within the scope of a block, are automatically assigned to the block.

There are a number of built-in attributes that influence the behavior of the compiler with respect to the block.

Setting the package attribute, for example, will make the compiler select only components with the specified package to be used in that component's slot.

Connecting it up¶

Any interface can be connected to any other interface of the same type using the ~ operator.

some_signal ~ another

Units and tolerances, assertions and maths¶

Remember how NASA slung a rocket straight into Mars because of a metric/imperial boo boo?

How about we don't do that again.

Units¶

Resistors's resistances must be a resistance; whether 1.23Ω (option+Z on OSx), 1.23ohm, 4.56Kohm, 7.89Mohm or similar.

Any attribute of any block may have a unit attached written (without a space) after any number.

Unsurprisingly, caps capacitances need to be a capacitance; eg. 23.4uF, various limits in volts, amperes, degrees and so on.

Add units.

Tolerances¶

Another unfamiliar first-class language feature when dealing with the physical world is the ability (and generally requirement) to spec tolerances for attributes.

You could try find a 10kΩ resistor, but my money says you won't - it'll likely be at least 10kΩ +/- 0.1% (which you can write!)

Tolerances can be written in the forms of: - 1V to 2V - 3uF +/- 1uF - 4Kohm +/- 1%

These are hopefully sufficiently intuitive as to not warrant further explanation 🤞

Units and Tolerances¶

With Units and Tolerances together, we can define physical attributes.

There's quite a few legal ways to combine them!

3V to 3.6V perhaps for a supply rail
3V +/- 10mV maybe for a reference
4.7uF +/- 20% for a generic cap
even 25lb +/- 200g 🤣

Sweet, so now I've got all these values around the place... what can I do with them?¶

Maths

There are two things that atopile can do for you with these values: 1. Check that assertions about their relationships to one another are true 2. Solve systems of constraints based on these relationships for find component values

This maths is all done including the units and tolerances, so you can be sure absolutely sure everything always works.

Use the assert keyword to apply constraints on the values of attributes to one another.

Supported operators are currently <, > and within (all are inclusive of the bounds).

a = 1 ± 0.1
b = 2 ± 0.2
c: resistance  # variable declaration without assignment

assert a < b  # always true before 0.9 and 1.1 (the bounds of a) are both lower than the bounds of b (1.8 and 2.2)
assert a > b  # always false --> Will yield a failure at compile time
assert c within 1Kohm to 10Kohm  # first solved for, then the solution is independently checked at the end of the build

I'm not sure about you, but I (Matt) am pretty dumb and don't love working too hard. Perhaps you've got a better method, but generally when I'm trying to find resistor values for something even as simple as a voltage divider, I guess one that seems approximately right, then calculate the other - giving me something that doesn't exist, before finally checking through a few other options close-by until finding a pair that works.

This is fine and dandy as long as you only care about the ratio of a voltage divider, but as soon as you need to check what that does for your regulators output voltage? Ergh, fine! What about the extremes of the tolerances on those resistors? Fine I'll do it once - but I swear if someone goes to tweak those values for whatever reason, I am unlikely to be pleased.

So, let's get atopile to do it for us!

atopile will automatically solve systems of constraints for you with free variables, and check that the values of attributes are within their tolerances.

Specialization¶

The -> operator will specialize a module from it's existing instance, to an instance of the type on the right hand side.

some_instance -> AnotherModuleType

This is useful for configuring a previously specified topology.

Imports¶

You can import assets by specifying what you want to import and where you want to import it from using the following syntax within your .ato files:

from "where.ato" import What, Why, Wow

Notes on that statement: - add quotes on the "where.ato" - it's a string - What, Why and Wow are capitalized because they are in the source file. It has to match precisely - it's a type and types should be capitalized, though this isn't enforced and you can import things other than types from other files

The import statements are with respect to the current project (the root of which is where your ato.yaml is placed), or within the standard library (.ato/modules/)

Warning

You'll likely see import statements in the form of import XYZ from "abc.ato". This is a legacy syntax and will be removed in the future. Please use the new syntax.

It also doesn't support importing multiple things on the same line.

1. Basics of the ato language¶