83C196LC Datasheet, PDF (7/22 Pages) Intel Corporation – CHMOS 16-BIT MICROCONTROLLER

Name
EXTINT
ONCE#
P0.7:2
P1.3:0
P2.7:6
P2.4
P2.2:0
P3.7:0
AUTOMOTIVE — 83C196LC, 83C196LD
Type
I
I
I
I/O
I/O
I/O
Table 4. Signal Descriptions (Continued)
Description
External Interrupt
In normal operating mode, a rising edge on EXTINT sets the EXTINT interrupt
pending bit. EXTINT is sampled during phase 2 (CLKOUT high). The minimum
high time is one state time.
In powerdown mode, asserting the EXTINT signal for at least 50 ns causes the
device to resume normal operation. The interrupt does not need to be enabled.
In idle mode, asserting any enabled interrupt causes the device to resume
normal operation.
EXTINT shares a package pin with P2.2.
On-circuit Emulation
Holding ONCE# low during the rising edge of RESET# places the
microcontroller into on-circuit emulation (ONCE) mode. This mode puts all pins
into a high-impedance state, thereby isolating the microcontroller from other
components in the system. The value of ONCE# is latched when the RESET#
pin goes inactive. While the microcontroller is in ONCE mode, you can debug
the system using a clip-on emulator.
To exit ONCE mode, reset the microcontroller by pulling the RESET# signal
low. To prevent inadvertent entry into ONCE mode, either configure this pin as
an output or hold it high during reset and ensure that your system meets the V_IH
specification.
ONCE# shares a package pin with P2.6.
Port 0
This is a high-impedance, input-only port. Port 0 pins should not be left floating.
Port 1
This is a standard bidirectional port that shares package pins with individually
selectable special-function signals.
Port 1 shares package pins with the following signals: P1.0/EPA0/T2CLK,
P1.1/EPA1, P1.2/EPA2/T2DIR, P1.3/EPA3.
Port 2
This is a standard bidirectional port that shares package pins with individually
selectable special-function signals.
P2.6 is multiplexed with the ONCE function. If this pin is held low during reset,
the device will enter ONCE mode, so exercise caution if you use this pin for
input. If you choose to configure this pin as an input, always hold it lowhigh
during reset and ensure that your system meets the V_IH specification to prevent
inadvertent entry into ONCE mode.
Port 2 shares package pins with the following signals: P2.0/TXD, P2.1/RXD,
P2.2/EXTINT, P2.6/ONCE#, P2.7/CLKOUT.
Port 3
This is a memory-mapped, 8-bit, bidirectional port with programmable open-
drain or complementary output modes. The pins are shared with the
multiplexed address/data bus, which has complementary drivers.
P3.7:0 share package pins with AD7:0.
ADVANCE INFORMATION
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