IBM 560E manual Bits, 0071, Mask, 0070

RT/CMOS

Address

and

NMI

Mask

Register

(Hex

0070)

The

NMI

mask register is used with the

RT/CMOS

data

register (hex

0071)

to

read from and write to the RT/CMOS

RAM

bytes.

Attention

The

operation

following

a

write to

hex

0070

should

access

hex

0071;

otherwise,

intermittent

failures

of

the RT/CMOS

RAM

can

occur.

Bit

Function

7

NMI

mask

6–0

RT/CMOS

RAM

address

Figure

2-13. RT/CMOS

Address and NMI Mask Register

(Hex

0070)

Bit 7

When this write-only bit is set to 1, the NMI is masked

(disabled). This bit is set

to

1 by a power-on reset.

Bits

6–0

These

bits

are

used

to

select

RT/CMOS

RAM

addresses.

RT/CMOS

Data

Register

(Hex

0071)

The

RT/CMOS

data

register is used with the

RT/CMOS

address

and

NMI

mask

register

(hex

0070)

to

read

from

and

write

to

the

RT/CMOS

RAM

bytes.

Bit

Function

7–0

RT/CMOS

data

Figure

2-14. RT/CMOS

Data Register

(Hex

0071)

ThinkPad 560/560E System Board 2-17