Tandy 1000 HX Technical Reference Manual page 150

. TANDY COMPUTER PRODUCTS
PIN #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
PIN NAME
CLK16M
WCK
FDCCLK
RDDATA
RDD
RDW
FRES/S
RW*/SEEK
TRKO*
F/TRKO
STEP*
GND
WRDATA*
WRE
WRD
PS1
PSO
FDCDMRQ*
FDCINT
DRQ
DMA/INTE
INT+
SWITCH
+ 5V
TYPE
INPUT
OUTPUT
OUTPUT
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
r
period = 2 u s , 250 ns pulse
If SWITCH = 1, period = 1 u s , 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
1.2 DESCRIPTION OF PINS: