Commodore 128 Programmer's Reference Manual page 596

586 COMMODORE 128
0
high, then a built-in function ROM has been selected. If MS0 alone is high, U
then an external function ROM has been selected. Finally, if both are high, the
RAM that occupies the particular slot has been selected. In C64 mode, the j
PLA completely ignores these lines. J
■ I/O: This output is used to select memory mapped I/O in C128 mode. It is on
pin 13, and is also known as MS2. In C128 mode, this line always reflects the ~
polarity of the I/O bit. It is ignored by the PLA in C64 mode, and remains (j
high throughout C64 mode.
■ C128: This output directs the system to act in either C128 or C64 mode. It is
located on pin 47, and is also known at MS3. It goes low to indicate C64 j I
mode, high for C128 mode. ^
■ /Z80EN: This output is used to enable the Z80 processor and disable the
normal operation of the 8502 processor. It can be found at pin 43. It goes low : -
to indicate Z80 mode, high for all other modes. JJ
■ /CASo-CASi: CAS enables to control RAM banking. CAS0 enables the first
bank of 64K; CAS! enables the second bank of 64K. These are pins 12 and
Irrespectively. JJ
ABSOLUTE MAXIMUM RATINGS
ITEM SYMBOL RANGE UNITS
Iitput Voltage VIn -2.0 to +7.0 Vdc
Supply Voltage Vcc -2.0 to+7.0 Vdc
Operating Temperature Ta 0to70 °C
Storage Temperature Tst -55 to 150 °C
Table 16-10. Absolute Maximum Ratings for the MMU
MAXIMUM OPERATING CONDITIONS
ITEM
Voltage Variance
Input Leakage Current
Input High Voltage
Input Low Voltage
Output High Voltage
(Ioh = -200»xA. Vcc =
Output Low Voltage
(Iol = -3.2mA, Vcc =
Maximum Input Current
SYMBOL
Vcc
Ii
Vih
Vil
Von
5V ± 5%)
VOL
5V ± 5%)
Ice
RANGE
5.0 ± 5%
-1.0
Vgs+2.4 to Vcc+1.0
Vss-2.0toVss+0.8
Vss + 2.4
Vss + 0.4
250
UNITS
Vdc
M-A
Vdc
Vdc
Vdc
Vdc
mA
Table 16-11. Maximum Operating Conditions for the MMU