Tandy 1000 SL Technical Reference Manual page 169

TANPY COMPUTER PRODUCTS
1.2 DESCRIPTION OF PINS:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
CLKl6M INPUT
WCK OUTPUT
FDCCLK OUTPUT
RDDATA
RDD
RDW
FRES/S
RW*/SEEK
F/TRKO
TRKO*
STEP*
GND
WRDATA*
WRE
WRD
PS1
PS 0
FDCDMRQ*
FDCINT
DRQ
DMA/ INTE
I NT+
SWITCH
t5v
INPUT
OUTPUT
OUTPUT
INPUT
INPUT
INPUT
OUTPUT
OUTPUT
OUTPUT
INPUT
INPUT
INPUT
INPUT
OUTPUT
OUTPUT
INPUT
INPUT
INPUT
INPUT
DESCRIPTION
Frequency
=
16.0000 Tolerance = loopmm
If SWITCH = 0, period
= 2
us, 250 ns pulse
If SWITCH = 1, period
= 1 us, 250 ns pulse
If SWITCH
= 0,
then CLK16M/4
If SWITCH = 1, then CLK16M/2
Serial data from FDD
Serial data from FDC
Read Data Window
Step pulses to move head to another cylinder
Specifies seek mode when high
From FDD, indicating head is on track
0
To FDC, indicating head is on track
0
Moves head of FDD
Ground
Serial Data to FDD
Write Enable
Serial Data from FDC
Write precompensation status
Write precompensation status
DRQ delayed by 1.0 usec.
Interrupt request
FDC DMA Request
DMA request and FDC interrupt enable
Interrupt request generated by FDC
0
= low density drive
1
=
high density drive
+5 Volts
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2