
80C196KB USER’S GUIDE
270651 – 48
NOTE:
*
Must be driven high or low.
**
V
SS3
was formerly the CDE pin. The CDE function is no longer available. This pin must be connectd to V
SS
.
Figure 13-9. 80C196KB Minimum Hardware Connections
left floating, they can float to a mid voltage level and
draw excessive current. Some pins such as NMI or
EXTINT may generate spurious interrupts if left un-
connected.
14.0 SPECIAL MODES OF
OPERATION
The 80C196KB has Idle and Powerdown Modes to re-
duce the amount of current consumed by the chip. The
80C196KB also has an ONCE (ON-Circuit-Emulation)
Mode to isolate itself from the rest of the components
in the system.
14.1 Idle Mode
The Idle Mode is entered by executing the instruction
‘IDLPD
Ý
1’. In the Idle Mode, the CPU stops execut-
ing. The CPU clocks are frozen at logic state zero, but
the peripheral clocks continue to be active. CLKOUT
continues to be active. Power consumption in the Idle
Mode is reduced to about 40% of the active Mode.
The CPU exits the Idle Mode by any enabled interrupt
source or a hardware reset. Since all of the peripherals
are running, the interrupt can be generated by the HSI,
HSO, A/D, serial port, etc. When an interrupt brings
the CPU out of the Idle Mode, the CPU vectors to the
corresponding interrupt service routine and begins exe-
cuting. The CPU returns from the interrupt service
routine to the next instruction following the ‘IDLPD
Ý
1’ instruction that put the CPU in the Idle Mode.
In the Idle Mode, the system bus control pins (ALE,
RD, WR, INST, and BHE), go to their inactive states.
Ports 3 and 4 will retain the value present in their data
latches if being used as I/O ports. If these ports are the
ADDR/DATA bus, the pins will float.
It is important to note the Watchdog Timer continues
to run in the Idle Mode if it is enabled. So the chip
must be awakened every 64K state times to clear the
Watchdog or the chip will reset.
14.2 Powerdown Mode
The Powerdown Mode is entered by executing the in-
struction, ‘IDLPD
Ý
2’. In the Powerdown Mode, all
internal clocks are frozen at logic state zero and the
oscillator is shut off. All 232 bytes of registers and most
peripherals hold their values if V
CC
is maintained.
Power is reduced to the device leakage and is in the uA
range. The 87C196KB (EPROM part) will consume
more power if the EPROM window is not covered.
69
数控原理与维修
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Содержание 80C196KB Series
Страница 1: ...November 1990 80C196KB User s Guide Order Number 270651 003 http www agreenleaf cn...
Страница 59: ...80C196KB USER S GUIDE Figure 11 7 Ideal A D Characteristic 270651 37 55 http www agreenleaf cn...
Страница 60: ...80C196KB USER S GUIDE Figure 11 8 Actual and Ideal Characteristics 270651 38 56 http www agreenleaf cn...
Страница 61: ...80C196KB USER S GUIDE Figure 11 9 Terminal Based Characteristic 270651 39 57 http www agreenleaf cn...
Страница 70: ...80C196KB USER S GUIDE Figure 13 5 Reset Sequence 80C196KB Reset Sequence 270651 45 66 http www agreenleaf cn...
Страница 83: ...80C196KB USER S GUIDE 270651 80 Figure 15 14 AC Timing Diagrams 79 http www agreenleaf cn...
Страница 84: ...80C196KB USER S GUIDE 270651 81 270651 84 Figure 15 14 AC Timing Diagrams Continued 80 http www agreenleaf cn...