SW version history (partly):

version 8.3:

- New base version for PCB HW V 3.01

- Change of quality measurement towards new approach

- New setup option Ratio for quality measurement

- Exclusion of frequency measurement

version 7.01

- fix timing issue for EADOGM LCD-displays with PIC at 32 MHz (too short data hold time); not relevant for standard 16x2 LCD-displays 

HW version history:

version 3.01:

- Complete redesign of PCB to fit into enclosure TB-2B from TEKO

- Change of quality measurement towards new approach (#swings to be counted via comparator hyteresis)

- Better decoupling of oscillator by using Schottky diode

- DC coupling for buffer and comparator, switchable resistor network

- Exclusion of external frequency measurement

- Switch towards battery supply only

- Exclusion of 2nd display type and 2nd button type

version 2.3

- third PCB version

- introduction of latching relays to save power

- change of quarz from 20 MHz to 8 MHz. Together with PIC PLL this will lead to a PIC frequency of 32 MHz for further SW improvements

- change of boost converter from TPS61222 to MCP1640. The MCP 1640 is able to deliver a lot more power.

version 2.2

- design of new PCB version, not yet tested

- exclusion of TPS61222 boost converter and change of layout to allow supply by the other 2 supply options

version 2.1.1

- design of new PCB version, but actually changed it manually on available PCB version 2

- change on the peak detektor to closed loop design and reducted parasitic inductance

version 2.1

- design of new PCB version, but actually changed it manually on available PCB version 2

- change on the peak detektor to open loop design for faster slew rates

version 2

- second PCB version

- redesign DUT configuration unit to save one relay; reduction of parasitic capacity and current consumption

- redesign of oscillator for lower parasitic capacity; introduction of negative supply chain to enable measurement against ground

- redesign of power supply section with negative supply chain and introduction of batterie support via boost converter

- introduction of multiple assembly alternatives for LCD, buttons for easier housing

- discontinuation of Reset button and corresponding parts

- introduction of 4 mm panel sockets for better mechanical stability

- introduction of simple functionality to measure external frequency

- optimization of layout for better power supply, ground plane

version 1

- first PCB version

- several iterations on software, some changes on layout; basically all of the functionallity available

version 0.1

- prototype on breadboard Eurocard size with basic functionallity

version 0.0

 - prototype on solderless breadboard to test basic idea