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Member Since 28 Dec 2010
Offline Last Active Oct 21 2016 11:28 PM

Topics I've Started

Bug: Netduino DHCP requests not asking for DNS

10 July 2013 - 04:12 PM

My Netduino Plus 2 (v4.2.2.2 Jan 26 2013) is working at home with networking, then I bring it to work today and network time protocol requests are failing.  I do some digging, and the DNS entry is my home router, not my work DNS.  DHCP is enabled, and the other parameters are okay (IP, subnet, router, etc.)


So I used WireShark to capture the relevant DHCP packets.  Netduino should be requesting DNS options but is not.  The BOOTP option 55 only includes Subnet Mask, Router, and Broadcast Address.  It should also include DNS as a requested parameter.  The DHCP server at home supplies the DNS entry anyways, but the DHCP server at work appears to be strictly complying with the parameter request and doesn't supply the DNS entry if not requested.


Option: (55) Parameter Request List Length: 3 Parameter Request List Item: (1) Subnet Mask Parameter Request List Item: (3) Router Parameter Request List Item: (28) Broadcast Address


There should be at least one more item included:

  Parameter Request List Item: (6) Domain Name Server


Relevant packet dump from work is attached.

I2C Software Workaround for Plus 2

30 November 2012 - 07:46 AM

This SoftwareI2CBus class can be used to help workaround Netduino Plus 2 I2C problems.

I was able to successfully read from my I2C EEPROM. Another advantage is that you can choose to use different pins too.

(Note this leverages a software I2C driver written by our peers over at tinyclr and GHI. Note that a portion must be downloaded from the tinyclr site (link will show when you try to compile). The value I added was to replace the custom APIs with ones more compatible with the standard I2C APIs. Known issue: read/write timeouts are either fixed or otherwise ignored.)

Good luck guys! The Netduino Plus 2 is a great platform, and hopefully this can help one or two folks that hit the early defects in I2C.

Usage comparison between hardware and software I2C:

#define I2C_SOFTWARE
            SoftwareI2CBus i2cbus = new SoftwareI2CBus(Pins.GPIO_PIN_A5, Pins.GPIO_PIN_A4);
            SoftwareI2CBus.I2CDevice i2c = i2cbus.CreateI2CDevice(new I2CDevice.Configuration(0x50, 400));
            I2CDevice i2c = new I2CDevice(new I2CDevice.Configuration(0x50, 400));

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