Microsoft RAMCard C-97200 - Manual (Page 26)

$C083
—
16253 0011 Selects RAMCard RAM read, BANK 2, and
write-enables RAMCard RAM if address ac
cessed twice consecutively
$C088
—16248
1000 Selects RAMCard RAM read, BANK 1, and
RAMCard RAM write-protect
$C089
—16247
1001 Selects Apple on-board ROM read, BANK 1,
and write-enables RAMCard RAM if address
accessed twice consecutively
$CO8A
-16246
1010 Selects Apple on-board ROM read, BANK 1,
and RAMCard RAM write-protect
$CO8B
—16245
1011 Selects RAMCard RAM read, BANK 1, and
write-enables RAMCard RAM if address ac-
cessed twice consecutively
NOTE: If RAMCard RAM was already in a write-enabled state, only a
angle access of a write-enable control address ($C081, $C083, $C089,
$C08B) is necessary to remain in a write-enable state until a write-
protect control address is accessed. (This state applies immediately
following power on.)
Additional Technical Details
The topics in these sections include status bits, the LED Indicators on
RAMCard, and RAMCard hardware details.
Status Bits
Whenever a read is performed to any of the control addresses which
alter RAMCard functions, the lower four bits of data returned show
the status JUST PRIOR to the read.
The four status hits (not to be confused with the bits of the control
address) indicate:
BANK SELECT
—
When BANK I is selected, status bit 0 will be
high. When BANK 2 is selected, status hit 0 will be low. This
state applies immediately following power on.
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