1# rail
2
3## Description
4A voltage rail produced by a regulator.
5
6Voltage regulators produce one or more rails.  Each rail typically provides a
7different output voltage level, such as 1.1V.
8
9On a PMBus regulator with multiple rails, the current rail is selected using
10the PAGE command.  Subsequent PMBus commands are sent to that PAGE/rail.
11
12## Properties
13| Name | Required | Type | Description |
14| :--- | :------: | :--- | :---------- |
15| comments | no | array of strings | One or more comment lines describing this rail. |
16| id | yes | string | Unique ID for this rail.  Can only contain letters (A-Z, a-z), numbers (0-9), and underscore (\_). |
17| configuration | no | [configuration](configuration.md) | Specifies configuration changes that should be applied to this rail.  These changes usually override hardware default settings.  The configuration changes are applied during the boot before regulators are enabled. |
18| sensor_monitoring | no | [sensor_monitoring](sensor_monitoring.md) | Specifies how to read the sensors for this rail. |
19
20## Example
21```
22{
23  "comments": [ "Vdd rail on PAGE 0 of the Vdd/Vio regulator" ],
24  "id": "vdd",
25  "configuration": {
26    "volts": 1.1,
27    "rule_id": "set_page0_voltage_rule"
28  },
29  "sensor_monitoring": {
30    "rule_id": "read_ir35221_page0_sensors_rule"
31  }
32}
33```
34