Tandy 1000 HX Technical Reference Manual page 20

• TANDY COMPUTER PRODUCTS •
14
MEMR*
CLK
OSC
NMI
RDYIN
RESET
BREQ*
AEN
IR2
IR3
IR4
0
0
0
I
I
0
I
0
I
I
I
MEMORY READ STROBE
CPU CLOCK
OSCILLATOR
NON-MASKABLE
INTERRUPT
SYSTEM WAIT
SYSTEM RESET
BUS REQUEST
BUS GRANT
INTERRUPT REQUEST*2
INTERRUPT REQUEST*3
INTERRUPT REQUEST*4
Alternate external
source
7.16MHz, 50% duty cycle
or
4.77MHz, 33% duty cycle
SOURCE: U23
Drive - 75/7.5 UL
14.32MHz, 50% duty
cycle
SOURCE: U23
Drive - 75/7.5 UL
To System NMI
Load: 1/1 UL, U16
SOURCE: OPEN-COLLECTOR
OR 3-STATE BUFFERS
Load: 1 UL and 1.0K ohm
pull-up. 10/0.9 UL
Set LOW by Peripherals
(I/O or Memory) to
extend READ or WRITE
cycles.
Power On or Manual
SOURCE: U23
Drive: 75/7.5 UL
From external masters
Load: 1 UL and 10K ohm
pull-up. 10/0.9 UL
To external masters
SOURCE: U23
Drive - 75/7.5 UL
To system interrupt
controller
Load: 1 UL and 2.2K
pull-down