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Old 30 October 2011, 12:38   #115
Toni Wilen
WinUAE developer
 
Join Date: Aug 2001
Location: Hämeenlinna/Finland
Age: 42
Posts: 19,682
Gayle PCMCIA reset

I was implementing AROS m68k card.resource and noticed something interesting..

There are two methods to reset the card (activate CC_RESET line)

Method 1:

Activate: write to address 0x00A40000.B
Deactivate: read address 0x00A40000.B

Method 2:

Activate: set address 0x00DA9000.B bits 0 and 1.
Deactivate: clear bits 0 and 1.

Normally bits 0 and 1 do following:

Bit 0 = if set, hardware reset Amiga if PCMCIA card removed
Bit 1 = if set, cause bus error exception if PCMCIA card removed
(=does not make sense to have both set)

Interestingly A600 Gayle supports both methods, A1200 Gayle (I have AA-Gayle-R5) supports only second method. (I have heard rumors that some older AA-Gayle revisions support this method too? Can anyone confirm?)

Kickstart ROM code only uses method 1 = this explains A1200 PCMCIA reset problems (without using software or hardware fix)

I guess OS developers were never told about this hardware design change..

Final interesting feature: A600 Gayle reset features are completely separate, activating reset with method 1 and then clearing it with method 2 won't clear the reset state. (Or vice versa)
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