Oscilocopio Dso Nano V2

BenF V3 firmware users guide for Seeed Studio DSO Nano V1 and V2

BenF V3 firmware users guide

DSO Nano V1

DSO Nano V2

Page 1 of 19

2012.01.01

V3.6

Revision 4

Introduction
The BenF V3 firmware has been developed to overcome some of the limitations and issues with the official firmware releases. In particular this applies to improved SD card support, a more advanced noloss sampling algorithm and a more intuitive user interface. The firmware is designed to run on Seeed Studio DSO Nano V1 and V2 hardware. It may or may not work with hardware supplied by other manufacturers. The firmware is free of charge to individuals in its binary format and is put into the public domain in the hope that it will be useful for others and not only the author. Any use of thisfirmware is at your own risk. No express or implied warranty is granted for the firmware or related documentation and under no circumstance can the author be held responsible for any direct or consequential damage that may arise from using it.

Background
The DSO Nano first appeared in the market fall 2009 with a compact attractive design and a very competitive price. Despite its limited bandwidth,the Nano is nonetheless and excellent tool for a range of practical measuring tasks such as basic electronics design/repair and auto/marine diagnostics. The stock firmware however is very basic and despite a few updates along the way, much is still left to be desired. Even with the most recent official 2.5e release, we’re not much further than a pretty enclosure with potential. To realize thispotential, a complete rewrite of the firmware was needed. A key feature of any digital oscilloscope is its data acquisition capability and to get this right we need a three phase approach to sampling. That is pre-fetch, trigger-fetch and post-fetch. An acquisition must run uninterrupted until a trigger is found (forever if need be) while the sampling buffer is continually reused in a round-robinfashion. No samples must be lost or disregarded during the entire acquisition cycle. When a trigger is found, its position in the Page 2 of 19 2012.01.01 V3.6 Revision 4

buffer is marked and acquisition continues until the entire sampling buffer is filled with data. The data from this acquisition cycle is then displayed with the trigger point centered on the screen. The official DSO Nano firmware isusing the simplistic single phase acquisition model. That is start acquisition, stop acquisition and then search for a trigger. An issue with this approach is that the trigger (the data of interest) may arrive while we’re not acquiring data and so will be lost. This makes it more or less unfit for digital analysis (e.g. SPI, I2C, RS-232, RS-485) and also of limited use for signals like electronicignition (narrow, infrequent pulses) and many (if not most) other real life measuring and fault finding challenges.

Page 3 of 19

2012.01.01

V3.6

Revision 4

Feature Summary
Thanks to Seeed Studio and its DSO forum, sufficient information has been provided to allow the stock firmware to be replaced with a custom version. Based in part on the official 2.5e source release, V3 hasbeen developed as a complete new firmware replacement. Fixes and new features include the following:  Three phase sampling (pre-fetch, trigger-fetch, post-fetch) guaranteed never to miss infrequent events  More efficient screen update (10-100 times faster than version 2.5e)  Eliminate all flickering and stuck pixels  Code is re-written to allow full compile time optimization (much faster, compactand more responsive code)  A number of overflow bugs have been fixed (calculations for large time/div settings)  Scan has been replaced with a proper continues real-time scan mode  Configuration profiles can be saved to and restored from SD card or flash memory (default power on settings).  Waveforms can be saved to and restored from SD cards  Screen capture can be saved to bitmap files on...