ST10 STMICROELECTRONICS [STMicroelectronics], ST10 Datasheet - Page 22

• Manufacturer Part Number: ST10
• Description: 16-BIT MCU WITH 32K BYTE ROM
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

ST10C167
XI - PARALLEL PORTS
The ST10C167 provides up to 111 I/O lines orga-
nized into eight input/output ports and one input
port.
All port lines are bit-addressable, and all input/out-
put lines are individually (bit-wise) programmable
as input or output via direction registers. The I/O
ports are true bidirectional ports which are
switched to high impedance state when config-
ured as inputs.
The output drivers of five I/O ports can be config-
ured (pin by pin) for push/pull operation or
open-drain operation via control registers. During
the internal reset, all port pins are configured as
inputs.
The input threshold of Port 2, Port 3, Port 7 and
Port 8 is selectable (TTL-or CMOS-like), where
the special CMOS-like input threshold reduces
noise sensitivity due to the input hysteresis.
The input thresholds are selected with bit of
PICON register dedicated to blocks of 8 input pins
(2-bit for port2, 2-bit for port3, 1-bit for port7, 1-bit
for port8).
22/65
All pins of I/O ports also support an alternate pro-
grammable function:
– Port0 and Port1 may be used as address and
– Port 2, Port 7 and Port 8 are associated with the
– Port 3 includes the alternate functions of timers,
– Port 4 outputs the additional segment address
– Port 5 is used as analog input channels of the
– Port 6 provides optional bus arbitration signals
All port lines that are not used for alternate func-
tions may be used as general purpose I/O lines.
data lines when accessing external memory.
capture inputs or with the compare outputs of
the CAPCOM units and/or with the outputs of
the PWM module.
serial interfaces, the optional bus control signal
BHE and the system clock output (CLKOUT).
bits A16 to A23 in systems where segmentation
is enabled to access more than 64K Byte of
memory.
A/D converter or as timer control signals.
(BREQ, HLDA, HOLD) and chip select signals.