Normal Floppy Mode
Normal mode. Register 3F3 contains only bits 0 and 1. When this register is read, bits 2 - 7 are a
high impedance.
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
REG 3F3 Tri-state Tri-state Tri-state Tri-state Tri-state Tri-state tape sel1 tape sel0
Enhanced Floppy Mode 2 (OS2)
Register 3F3 for Enhanced Floppy Mode 2 operation.
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
REG 3F3 Reserved Reserved
Drive Type ID
Floppy Boot Drive
tape sel1 tape sel0
Table 7 - Drive Type ID
DIGITAL OUTPUT REGISTER REGISTER 3F3 - DRIVE TYPE ID
Bit 1
Bit 0
Bit 5
Bit 4
0
0
1
1
0
1
0
1
L0-CRF2 - B1
L0-CRF2 - B3
L0-CRF2 - B5
L0-CRF2 - B7
L0-CRF2 - B0
L0-CRF2 - B2
L0-CRF2 - B4
L0-CRF2 - B6
Note:
L0-CRF2-Bx = Logical Device 0, Configuration Register F2, Bit x.
20
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