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Old 30 August 2015, 13:16   #332
Toni Wilen
WinUAE developer
 
Join Date: Aug 2001
Location: Hämeenlinna/Finland
Age: 42
Posts: 19,522
I looked at wrong diagram, A2386SX floppy controller has 16MHz crystal and 1.4M floppy control rate register should have value of 0 but BIOS sets 2 (which equals 720k floppy). For some odd reason both 720k and 1.4M BIOS settings use rate value 2. (1.2M and others use correct values)

My guess is that there is some hidden non-emulated IO bit that BIOS uses to detect if drive is Amiga 1760k drive (which runs at halved speed = 1.4M floppy bit rate equals 720k floppy) or real 1.4M PC drive and BIOS thinks 1760k drive is in use, not real PC 1.4M drive.

(btw, if you take screenshots from VGA mode display, please untick "scale if smaller than display size" checkbox to get 1:1 pixel mapping)
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