Treasure Hunter P.I. Mark Paul's firmware

Treasure Hunter P.I. Mark Paul's firmware
I have built the detector as detailed on geotech (seems a lot has gone misssing there)
Marks firmware assembles OK. And the detector runs. I used the PIC16F84A as the 16C84 is hard to get. Clock is at 4MHz.
Using the re comended coil, the coil drive circuit uses too much current and pulls down the battery voltage st oping the uP
Using a coil with a lot of turns and a high resistance all features of the detector work fine but for obvious reasons the power
is too low. The pulse width is far too long and is the problem.

Have others built this detector with Mark's firmware version? Were there later modifications to the design? I have found a few errors in the schematic but the board is OK. I have researched this design here and everywhere I could for weeks now. I have found very little still exists??? Can anyone shed light on this.
Regards Eric

http://www.thunting.com/smf/specific_brands_reviews/treasure_hunter_pi_mark_pauls_firmware-t60437.0.html;new#new

It apears that the firmware from mark is flawed. It allows the pulse width to be reduced but will not store the new settings so that after power down and power up again it reverts to the long pulse width and high current.
Eric

Firmware has been modified detector working and accepts commands.
Thanks Mark, Mark and Maxine for all the work and a good design.
Eric.