IBM 5150 PC Technical Reference (6025005, August, 1981) (PDF)

Interrupt 6
DMA 2
100 Disk Format
1 Head, 45 cylinders, 8 sectors/TRK, 512 bytes/sector,MFM.
FDC Constants
N: H'02', SC: 08, HUT: F, SRT: C, GPL FORMAT: H'05',
GPL RD/WR: 2A, HLT: 01, (8ms track-track)
Drive Constants
HD Load 35 ms
HD Settle 25 ms
Motor Start 500 ms
Comments
1. Head loads with drive select, wait HD Load time before RD/WR
2. Following access, wait HD Settle time before RD/WR
3. Drive motors should be off when not in use. Only A or B and C or D
may run simultaneously. Wait Motor Start time before RD/WR ,..-.....,
4. Motor must be on for drive to be selected.
5. Data Errors can occur while using a Home Television as the
system display. Locating the TV too close to the diskette area can
cause this to occur. To correct the problem, move the TV away
from, or to the opposite side of the System Unit.
System I/O Channel Interface
All signals are TTL compatible:
MPUL 5.5 Vdc
LPUL 2.7 Vdc
MPDLO.5 Vdc
LPDL -0.5 Vdc
The following lines are used by this adapter.
+DO-7 (Bidirectional, Load: 1 74LS; Driver: 74LS 3-state) ~
These eight lines form a bus by which all commands,
status, and data are transferred. Bit 0 is the loworder
bit.
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