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FEZ Domino: Minimum SPI clock?


#1

I am curious if there is a minimum SPI Clock rate on the FEZ Domino. I have been experimenting with Newhaven Displays which apparently want a SPI clock of 100Khz. If I try to run the display with a higher clock rate, it drops characters, but if I try to reduce the clock to 100Khz, I get a System.InvalidOperationException when I try to write to the Display.


            SPI.Configuration spiConfig = new SPI.Configuration((Cpu.Pin)FEZ_Pin.Digital.Di9, false, 0, 0, true, true, 100, SPI.SPI_module.SPI1);
            spiInterface = new SPI(spiConfig);
...
            spiInterface.Write(data); // exception thrown here.


The slowest clock I can successfully set is 200Khz, but the display drops characters at that speed.


#2

This is one thing we are trying to improve in the release coming shortly.

More details come in few days


#3

Hi, I was wondering if there has been any progress on lowering the clock rate, I’m trying to talk to one of these http://www.sparkfun.com/products/760 and it has a minimum clock speed of 125KHz, I’m trying to run at 150Hz (the lowest I can seem to set) but it’s dropping data.

Cheers,

Stephen.


#4

Next SDK is coming out in few days and it will include the low SPI clock rate.


#5

Thanks for the update, I’ll keep an eye out for it.


#6

I’m also interested in low SPI clock. I was happy to find the nbew framework (from April 21th).
Unfortinatly I found that the minimun clock frequnecy ist still around 150kHz.
I also found that the version number of the assemlby is still 4.1.5.0 instead of 4.1.5.1
Could that be the reason that the new version does not work?

Thanks

Regards

Daniel


#7

What device are you using and please provide code example.


#8

I’m using FEZ Panda II board. The code I use is the following:


using System;
using System.Threading;

using Microsoft.SPOT;
using Microsoft.SPOT.Hardware;

using GHIElectronics.NETMF.FEZ;

namespace FEZ_Panda_II_Application1
{
    public class Program
    {
        public static void Main()
        {
         SPI.Configuration MyConfig = new SPI.Configuration((Cpu.Pin)FEZ_Pin.Digital.Di0,false,0,0,false,true,10,SPI.SPI_module.SPI1);
            SPI MySPI = new SPI(MyConfig);
            byte[] tx_data = new byte[8]; 
            byte[] rx_data = new byte[8];
   
            while (true) {
                MySPI.WriteRead(tx_data, rx_data);           
            }
        }

    }
}

With frequency o 150kHz instead of the used 10kHz no expection is raised.

Regards

Daniel


#9

Please double check that you installed the latest SDK the version number should be 4.1.5.1 when you look up hardware capabilities in MFDeploy.


#10

I checked the version and it is definitely 4.1.5.0
I desintalled the GHI SDK, checked that all files are gone and installed the latest SDK again with the same results.
I checked the versions of all DLL files in the assemblies directory and all are with version 4.1.5.0 except of the file “GHIElectronics.NETMF.W5100.Dhcp.dll” which has 4.1.5.1

Regards

Daniel


#11

There is a file called “release notes” right in the GHI SDK installed on your PC. Please open it and match it to this http://www.tinyclr.com/release-notes/


#12

I checked, it matches.


**********************************************************
GHI Electronics, LLC
NETMF SDK for NETMF v4.1
**********************************************************
SDK Version 1.0.14
April 11, 2011
======================================


#13

Jack,

Please update the firmware and then recheck the firmware version number using MFDeploy. There is a video under the download page on how to do that. Firmware version number should be 4.1.5.1

[quote]SDK Version 1.0.14 April 11, 2011
• USBizi (FEZ Mini, FEZ Domino, FEZ Rhino, FEZ Panda) V 4.1.5.1
[/quote]


#14

sorry it was my mistakte. :-[
After upgrading the internal firmware everything works fine down to 1kHz.
Thanks you for your great support.

Regards

Daniel