[Coco] How does the SCS line / GIME Setting Work?

[Darren A]

On 6/19/10, jdaggett at gate.net wrote:
> The MC2 bit of the INIT0 ($FF90) register controls what is encoded onto the
> S BUSS when
> the MPU addresses in the range of $FF40 to $FF5F. Only a 16 bit window is
> active at
> anytime. When the MC2 bit is set then we have the standard SCS which is
> encoded as $011
> on the S BUS and then when the MPU addresses in the range of $FF40 to $FF4F
> then bit #6
> of the LS138 is asserted low.

---

That is not correct.  When the MC2 bit is set, the entire 32-byte
range of FF40-FF5F causes bit 6 of the LS138 to go low. This matches
the way the SAM works.

Darren