405 Line Pattern Generator
A PIC based 405 line pattern generator that produces 16 test patterns including two test cards.
This is the download page for the PICGEN article that appeared in the Autumn 2016 issue of 'The Bulletin'. The article can be downloaded from the BVWS details can be found on there website bvws.org.uk
It has been found that some TV's can display a hum bar while using the Generator. This is due to the Field Frequency not been exactly 50 Hz. In light of this the Firmware has been updated to bring the Field rate closer to 50 Hz. The file name for the new Firmware is picgen_16_18f2685_v02 which supersedes picgen_16_18f2685_v01.
In order to bring the Field Frequency closer to 50 Hz the total line length has been reduced from 99 µS to 98.66 µS. This has been achieved by reducing the line sync pulse by 0.34 µS.
If after using the new Firmware a hum bar is still displayed it may be necessary to change the Resonator for a Crystal as some Resonators Frequency tolerance can be quite large.
A 6 MHz Crystal and it's associated load Capacitors can be fitted on the same PCB. A standard size Crystal can be fitted in the two outer holes in the PCB that were to take the Resonator. The load Capacitors can be fitted on the track side of the PCB between each pin of the Crystal and the center pad. Through hole components can be tacked on or SMD size 0805 Capacitors fits nicely between the pads.
To download the Firmware Right click it and choose "Save Link As..."
This Firmware suits PIC18F2685 and PIC18LF2685 microcontrollers.
It is a mirror image of the foil so is suitable for making a PCB using the laser printer method.
All material including Downloads on these pages is provided 'as is' without warranty of any kind, either express or implied.