87C196 Intel Corporation, 87C196 Datasheet - Page 9

• Manufacturer Part Number: 87C196
• Description: CHMOS 16-BIT MICROCONTROLLER
• Manufacturer: Intel Corporation

PORT 3 and 4
P2 7 CLKOUT
P2 6 HLDA
P2 5 HLD
(CB only)
P2 4 INTOUT
P2 3 BREQ
(CB only)
P2 2 EXTINT
P2 1 RXD
P2 0 TXD
PORT 1 EPA0– 7
PORT 0 ACH0 –7
EPORT
(CB only)
TXCAN
RXCAN
Symbol
8-bit bidirectional I O ports with open drain outputs These pins are shared with the
multiplexed address data bus which has strong internal pullups
Output of the internal clock generator The frequency is the oscillator frequency
CLKOUT has a 50% duty cycle Also LSIO pin when not used as CLKOUT
Bus Hold Acknowledge Active-low output indicates that the bus controller has
relinquished control of the bus Occurs in response to an external device asserting the
HLD
Bus Hold Active-low signal indictes that an external device is requesting control of the
bus Also LSIO when not used as HLD
Interrupt Output This active-low output indicates that a pending interrupt requires use
of the external bus Also LSIO when not used as INTOUT
Bus Request This active-low output signal is asserted during a HOLD cycle when the
bus controller has a pending external memory cycle Also LSIO when not used as
BREQ
A positive transition on this pin causes a maskable interrupt vector through memory
location 203CH Also LSIO when not used as EXTINT
Receive data input pin for the Serial I O port Also LSIO if not used as RXD
Transmit data output pin for the Serial I O port Also LSIO if not used as TXD
Dual function I O port pins Primary function is that of bidirectional I O System function
is that of High Speed capture and compare EPA0 and EPA2 have another function of
T2CLK and T2DIR of the TIMER2 timer counter
8-bit high impedance input-only port These pins can be used as digital inputs and or as
analog inputs to the on-chip A D converter These pins are also used as inputs to
EPROM parts to select the Programming Mode
8-bit bidirectional standard and I O Port These bits are shared with the extended
address bus A16– A19 for CB PLCC A16 – A23 for CB QFP Pin function is selected on
a per pin basis
Push-pull output to the CAN bus line
High impedance input-only from the CAN bus line
signal Also LSIO when not used as HLDA
Name and Function
87C196CA 87C196CB
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