Update README.md

README.md

@@ -1,41 +1,41 @@
 # Generate BOM for Altium Projects
 
-Generate a BOM for an Altium project on AllSpice Hub using py-allspice.
+Generate a BOM output file for an Altium project on AllSpice Hub using [AllSpice Actions](https://learn.allspice.io/docs/actions-cicd).
 
 ## Usage
 
 Add the following steps to your actions:
 
 ```yaml
-# Checkout is only needed if columns.json is committed in the repo.
+# Checkout is only needed if columns.json is committed in your Altium project repo.
 - name: Checkout
   uses: actions/checkout@v3
 
 - name: Generate BOM
   uses: https://hub.allspice.io/Actions/generate-bom-altium@main
   with:
+    # The path to the Altium project file in your repo.
     project_path: Archimajor.PrjPcb
+    # A path to a JSON file mapping columns to the attributes they are from.
     columns: .allspice/columns.json
+    # [optional] The path to the output file that will be generated.
+    # Default: 'bom.csv'
     output_file_name: bom.csv
-```
-
-where `.allspice/columns.json` looks like:
-
-```json
-{
-  "part_number": ["PART", "MANUFACTURER #", "MPN"],
-  "manufacturer": ["Manufacturer", "MANUFACTURER", "MFG", "Mfg"],
-  "designator": ["Designator", "REFDES", "Refdes", "Ref"],
-  "part_id": ["_part_id"],
-  "description": ["PART DESCRIPTION", "_description"]
-}
+    # [optional] A comma-separated list of columns to group the BOM by. If empty
+    # or not present, the BOM will be flat.
+    # Default: ''
+    group_by: 'Part ID'
+    # [optional] The variant of the project to generate the BOM for. If empty
+    # or not present, the BOM will be generated for the default variant.
+    # Default: ''
+    variant: ''
 ```
 
 ### Customizing the Attributes Extracted by the BOM Script
 
 This script relies on a `columns.json` file. This file maps the Component
 Attributes in the SchDoc files to the columns of the BOM. An example for
-`columns.json` is:
+`columns.json` file content is:
 
 ```json
 {
@@ -69,3 +69,20 @@ attributes from overriding any of your own. You can use these like:
 By default, the script picks up a `columns.json` file from the working
 directory. If you want to keep it in a different place, or rename it, you can
 pass the `--columns` argument to the script to specify where it is.
+
+## Variants
+
+To generate the BOM for a variant of the project, pass the `--variant` argument
+to the script. For example:
+
+```yaml
+- name: Generate BOM
+  uses: https://hub.allspice.io/Actions/generate-bom-altium@main
+  with:
+    project_path: Archimajor.PrjPcb
+    columns: .allspice/columns.json
+    output_file_name: bom-lite.csv
+    variant: 'LITE'
+```
+
+When no variant is given, the BOM is generated without considering any variants.