PWM SCPI Commands

This document describes the SCPI command interface implemented in commands_pwm.c for PWM (Pulse Width Modulation) and frequency measurement/control on the Melexis IO STM32 platform.

Overview

The commands_pwm.c file provides SCPI-like commands for initializing, deinitializing, reading, and setting PWM and frequency on various pins. It also supports DMA and IRQ-based PWM input, as well as clock configuration for advanced timing features.

Supported Commands

DMA/IRQ/Clock/Deinit

Command Pattern	Description
:A0:PWM:DMA:INIT	Init A0 for PWM DMA Input
:A0:PWM:DMA?	Get A0 PWM DMA Data
:A0:PWM:IRQ:INIT	Init A0 for PWM IRQ Input
:A0:PWM:IRQ?	Get A0 PWM IRQ Data
:A0:CLK:INIT	Clock at A0 Init
:A0:CLK:FREQ	Set clock frequency at A0
:A0:DEINIT	Deinit A0 pin

PWM/Frequency/Output (A0-A3, SDA, SCL)

Command Pattern	Description
:A0:PWM:INIT	Init A0 as PWM input
:A0:PWM?	Read A0 PWM
:A0:FREQ:INIT	Init A0 as Frequency measure
:A0:FREQ?	Read A0 Frequency in Hz
:A0:OUT:INIT	Init A0 as PWM output
:A0:OUT:SET	Set A0 PWM output in Hz
:A0:OUT:SET:FREQ	Set A0 Frequency output
:A0:PWM:DEINIT	DeInit A0 PWM Out/In
...	... (same for A1, A2, A3, SDA, SCL)

Example for Other Pins

• Replace A0 with A1, A2, A3, SDA, or SCL for similar commands on those pins.

Connector/Other Pins (Commented/Planned)

• The file contains commented-out patterns for connector pins (e.g., :CON:SCLK:INIT) and other SPI/UART-related pins, which can be enabled or extended as needed.

Command Details

• DMA/IRQ/Clock/Deinit: Initialize or read PWM using DMA or IRQ, configure clock, or deinitialize.
• PWM:INIT/FREQ:INIT/OUT:INIT: Initialize pin for PWM input, frequency measurement, or PWM output.
• PWM?/FREQ?: Read PWM or frequency value from the pin.
• OUT:SET/OUT:SET:FREQ: Set PWM output duty or frequency.
• PWM:DEINIT: Deinitialize PWM on the pin.

Handler Functions

• CMD_Pwm_Init: Handles initialization and deinitialization for PWM/frequency modes.
• CMD_Pwm_Read: Reads frequency or PWM values.
• CMD_Pwm_Set: Sets PWM duty or frequency.
• CMD_PwmDmaInit, CMD_PwmDmaData: DMA-based PWM input.
• CMD_PwmIrqInit, CMD_PwmIrqData: IRQ-based PWM input.
• CMD_Clk, CMD_ClkFreq: Clock configuration.
• CMD_DeInit: Deinitialization of all PWM/clock/DMA resources.

Example Usage

• Init A0 as PWM input: :A0:PWM:INIT
• Read A0 frequency: :A0:FREQ?
• Set A1 PWM output: :A1:OUT:SET 50 (sets duty cycle)
• Set SCL frequency output: :SCL:OUT:SET:FREQ 1000 (sets frequency)
• Init A0 for PWM DMA: :A0:PWM:DMA:INIT
• Get A0 PWM DMA data: :A0:PWM:DMA? 10 (reads 10 samples)

Examples

Initialize PWM Input

Command sent:

:A0:PWM:INIT\n

Response:

(OK)>

Read PWM Value

Command sent:

:A0:PWM?\n

Response:

A0:PWM=1234
(OK)>

Set PWM Output Frequency

Command sent:

:A0:OUT:SET:FREQ 1000\n

Response:

(OK)>

Read Frequency

Command sent:

:A0:FREQ?\n

Response:

A0:FREQ=1000
(OK)>

Deinitialize PWM

Command sent:

:A0:PWM:DEINIT\n

Response:

(OK)>

Error Example (Invalid Pin)

Command sent:

:Z9:PWM:INIT\n

Response:

ERR: unknown pin
(Some error)>

Notes

• Commands are case-insensitive.
• The command interface is extensible; new pins or features can be added by updating the command table and implementing the corresponding handler logic.
• Some advanced or connector pin commands are present as comments and can be enabled as needed.