UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Karen's PICL

Phil__G · 21st Aug 2021, 11:09 pm

..forgot to say, on the NIBL 'restore' idea, I've found that you usually get away with just the two bytes of the 1st line number, but strictly there are 4 bytes that could need resetting. Using the # prefix for hex, on page 1 its
@#111F = #0D (documented as a dummy line end)
@#1120 = msb of 1st line number, usually zero
@#1121 = lsb of 1st line number, usually 10 but use 1 if unsure
@#1122 = 1st line byte count including line number and CR, this is corrupted by a scmp DLD as part of the power-up page test

on page 2 its
@#2001 = #0D
@#2002 = msb of 1st line number
@#2003 = lsb of 1st line number
@#2004 = 1st line byte count including line number and CR, this is corrupted by a scmp DLD as part of the power-up page test

Also found that programs that make use of TOP dont work in rom, you need to run something in page 1 to establish TOP and variable/string storage, then switch to page 2 and continue with these values. The TOP value reported by page 2 cant be used for R/W storage if its in rom!

21st Aug 2021, 11:09 pm	#40
Phil__G Octode Join Date: Mar 2011 Location: North Yorkshire, UK. Posts: 1,119	Re: Karen's PICL - PCB available ..forgot to say, on the NIBL 'restore' idea, I've found that you usually get away with just the two bytes of the 1st line number, but strictly there are 4 bytes that could need resetting. Using the # prefix for hex, on page 1 its @#111F = #0D (documented as a dummy line end) @#1120 = msb of 1st line number, usually zero @#1121 = lsb of 1st line number, usually 10 but use 1 if unsure @#1122 = 1st line byte count including line number and CR, this is corrupted by a scmp DLD as part of the power-up page test on page 2 its @#2001 = #0D @#2002 = msb of 1st line number @#2003 = lsb of 1st line number @#2004 = 1st line byte count including line number and CR, this is corrupted by a scmp DLD as part of the power-up page test Also found that programs that make use of TOP dont work in rom, you need to run something in page 1 to establish TOP and variable/string storage, then switch to page 2 and continue with these values. The TOP value reported by page 2 cant be used for R/W storage if its in rom!