Radio Shack TRS-80 Service Manual page 28

Bit 7" ENINTRO; 0 disables Disk INTRO from gener'ting
an NMI.
1
enables above.
NOTE: A
e
indicates the device is interrupting.
N,m,:
Port Address:
Access:
WANMIMASKREG'
0E4H
WRITE ONLY
MODEL III PORT BITS
Name:
Port Addren:
Access:
ROINTSTATUS·
0E0H
READ ONLY
Bit
6 ..
ENDRO; iii disables Disk ORO from generating an
NML
, enables above.
Bil 7 .. Undefined
Bit 6 .. RS-232 ERROR INT
Name:
Port Address:
Access:
RDNM 1STATUS·
0E4H
READ ONLY
Bit 5'" RS·232 RCV INT
Bit
4"
RS·232 XMIT INT
Bit 7 .. Status of Disk INTRQ: 1" False, 0 '" True
Bit 6 .. Status of Disk ORO; I " False, 0 '" True
Bit 5 .. Reset' StatUi; 1 = False, 0 - True
Bit
3 ..
lOBUS tNT
Bit 2 .. RTC INT
Bill'" CASSETTE (1500 Baud) INT F
BIt 0
~
CASSETTE (1500 Baudl tNT R
Bit 7 '" Undefined
Name:
Port Address:
Accesl:
MOD OUT
OECH
WRITEDNLY
Name:
Port Addrt$s:
Access:
CASQUT·
OFFH
WRITE ONLY
Bit 6 .. Undefined
Bit 5 '" DISWAIT; 0 di,ables video waits, 1 enables
Bit 4 .. ENEXTIO;
tJ
disabills external 10 Bus, 1 enables
Bil
3 '"
ENALTSET;
ca
disables alternate character set,
1
enables alternate video character set.
Bit
2 '"
MODSEL;
(I
enables
64
character mode,
I enables 32 character mode.
BIt
1 ' " '
CAStJlOTQRON;
0 turns
cassette motor off,
1 turns cassene motor on.
Bit II .. Undttfined
Bit 7 .. Undefined
Bit 6 ~ Undefined
Bit 5 '" Undefined
Bit 4 .. Undefined
Bit 3 '" Undfined
Bit
2 '"
Undefined
Bit 1 .. Cassette output level
Bit liI "'Cassent outpull,vel
21