Can anyone tell me how to translate I/O pins on the STM32F405 to PWM channels. I am using pins 41 and 42 which seem to be TIM1_CH1 and TIM1_CH2 respectively.
PWM pwmLEDb;
PWM pwmLEDc;
pwmLEDb = new PWM(Cpu.PWMChannel.PWM_1, 500, 100, false);
pwmLEDc = new PWM(Cpu.PWMChannel.PWM_2, 500, 100, false);
pwmLEDb.Start();
pwmLEDc.Start();
Using the code above nothing happens to the LEDs on these two pins.
What am I doing wrong?
C6 = 0
A7 = 1
C7 = 2
A8 = 3
B0 = 4
B1 = 5
B5 = 6
B4 = 7
B3 = 8
B11 = 9
B10 = 10
A10 = 11
A9 = 12
A15 = 13
B8 = 14
B9 = 15
So…
Pin 41 = PA8 == PWM3
Pin 42 = PA9 == PWM12
Obvious init :whistle:
It couldn’t be less obvious! How do you know this and I don’t? I don’t even know where to look in the netmf/STM documentation. Where could I have found your answer? Teach a man to fish…
Also, does the enum go up that that far?
It hasn’t felt like it this week. This stuff is addictive.
Only goes to 8…
The information for those pins is only available on the schematic for the Cerbuino devices.
[url]http://www.ghielectronics.com/downloads/schematic/FEZ_Cerb40_II_SCH.pdf[/url]
@ Mr. John Smith - So how do you tell from that schematic which pin is which PWM channel?
@ Justin, yea, you’d also need the device datasheet 
I have both but the answer is too well hidden to be straight forward to determine. If you have any insight I’d be grateful to receive it.
@ Jason - https://ghiopensource.codeplex.com/SourceControl/latest#Solutions/FEZCerberus/platform_selector.h
Re: “Can anyone tell me how to translate I/O pins on the STM32F405 to PWM channels”
The Datasheet is wrong. Its posted in the specs section about the error in the Datasheet and Pin Maps but I cant find it now. Site Changes…
EDIT: Found it:
[b]
Known Issues
Hardware
On boards version 1.1, sockets 5 and 6 are mislabeled. These sockets have PWM feature so they should also include P socket type.
[/b]
Page removed but I had a saved copy…
Where PWM is shown to be X5 and X6 on the Datasheet, its incorrect and its actually on X3 and X4, Pins 7, 8 and 9 See below.
I have started some code on the register access to configure PMW, see: https://www.ghielectronics.com/community/codeshare/entry/931
Also I wonder if this may help some, I wrote a helper class:
public sealed class PWMChannel : PWM
{
#region PWM Pin Outs...
// X3...
// Pin 7
// Pin 8
// Pin 9
// X4...
// Pin 7
// Pin 8
// Pin 9
#endregion
#region Below does not work...
// X5...
// Pin 7
// Pin 8
// Pin 9
// X6...
// Pin 7
// Pin 8
// Pin 9
// X8...
// Pin 7
#endregion
/////////////////////////////////////////////////////////////////////////
// See for more information: //
// http://msdn.microsoft.com/en-us/library/jj633523(v=vs.102).aspx //
// http://msdn.microsoft.com/en-us/library/jj646655(v=vs.102).aspx //
/////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////
// References the Library: "Microsoft.SPOT.Hardware.PWM" //
// Add using statement: using Microsoft.SPOT.Hardware; //
///////////////////////////////////////////////////////////////
/// <summary>
/// Get or Set PWMChannel's Frequency using the inhetited member 'Frequency'...
/// </summary>
private uint ChannelFrequency
{
get { return (uint)Frequency; }
set { Frequency = value; }
}
/// <summary>
/// Get or Set the PWMChannel's Duty Cycle using the inhetited member 'DutyCycle'...
/// </summary>
private double ChannelDutyCycle
{
get { return DutyCycle; }
set { DutyCycle = value; }
}
/// <summary>
/// Channel 1 - Set for output on Pins 8 on X3.
/// </summary>
public static PWMChannel Channel_1 = new PWMChannel(Cpu.PWMChannel.PWM_1, 10, 0, GlobalVariable.InvertChannel_1);
/// <summary>
/// Channel 2 - Set for output on Pins 9 on X3.
/// </summary>
public static PWMChannel Channel_2 = new PWMChannel(Cpu.PWMChannel.PWM_2, 10, 0, GlobalVariable.InvertChannel_2);
/// <summary>
/// Channel 3 - Set for output on Pins 8 on X4.
/// </summary>
public static PWMChannel Channel_3 = new PWMChannel(Cpu.PWMChannel.PWM_3, 10, 0, GlobalVariable.InvertChannel_3);
/// <summary>
/// Channel 4 - Set for output on Pins 9 on X4.
/// </summary>
public static PWMChannel Channel_4 = new PWMChannel(Cpu.PWMChannel.PWM_5, 10, 0, GlobalVariable.InvertChannel_4);
/// <summary>
/// Stop Set Parameters and Start PWM on the desired Configuration...
/// </summary>
/// <param name="frequency_Hz">The Frequency in Hertz</param>
/// <param name="dutyCycle">Duty Cycle expressed in Percentage EG: 0.5 gives 50% Duty Cycle of the Frequency</param>
/// <param name="invert">Inverts the Output Pin</param>
public void Configure(uint frequency_Hz, double dutyCycle)
{
this.Stop();
ChannelFrequency = frequency_Hz;
ChannelDutyCycle = dutyCycle;
this.Start();
}
/// <summary>
/// All Stop! Stops the Channel's PWM...
/// </summary>
public void ChannelStop()
{
this.Stop();
}
/// <summary>
/// Standard Constructor, explicit PWM Inheritance.
/// </summary>
/// <param name="channel">The Cpu.PWMChannel Channel</param>
/// <param name="frequency_Hz">The Frequency in Hertz</param>
/// <param name="dutyCycle">Duty Cycle expressed in Percentage EG: 0.5 gives 50% Duty Cycle of the Frequency</param>
/// <param name="invert">Inverts the Output Pin</param>
private PWMChannel(Cpu.PWMChannel channel, uint frequency_Hz, double dutyCycle, bool invert) : base(channel, frequency_Hz, dutyCycle, invert)
{
Debug.Print("PWMChannel Class Instantiated - First Constructor called...");
}
/// <summary>
/// Standard Constructor, explicit PWM Inheritance.
/// </summary>
/// <param name="channel">The Cpu.PWMChannel Channel</param>
/// <param name="period">The period of the pulse in microseconds.</param>
/// <param name="duration">The duration of the pulse in microseconds. This value should be a fraction of the period parameter.</param>
/// <param name="scale">PWM.ScaleFactor Enumeration - Provides scale factor values for duration and period.</param>
/// <param name="invert">Inverts the Output Pin</param>
private PWMChannel(Cpu.PWMChannel channel, uint period, uint duration, PWM.ScaleFactor scale, bool invert) : base(channel, period, duration, scale, invert)
{
Debug.Print("PWMChannel Class Instantiated - First Constructor called...");
}
} // END of Class...
This code does actually make some features come to life, EG: PWM Changes are much better…
To Use this Code:
PWMChannel.Channel_1.Configure(184000, 0.5);
All the best
Chris
Just to help out some more, I wanted to share some information, some I just gained by experimenting.
NOTE: PAx, or PCx relates to the GPIO Port, EG: GPIOC, or GPIOA where x is the Number of the Pin 0 - 15 for each GPIO Port.
Also NOTE: Each Timer can have multiple Channels, Channel 1 through 4 for most Timers. The CCMR1 and CCMR2 Register control the functionality of the Channels. These Channels have nothing to do with the Cpu.PWMChannel.PWM_x Channels in the Microsoft Class.
Pin to Channel to Timer Mapping is as follows. See attached Picture: