ST90158 - I/O PORTS
INPUT/OUTPUT BIT CONFIGURATION (Cont’d)
Figure 50. Basic Structure of an I/O Port Pin
I/O PIN
PUSH-PULL
TRISTATE
OPEN DRAIN
WEAK PULL-UP
TTL / CMOS
(or Schmitt Trigger)
TO PERIPHERAL
INPUTS AND
INTERRUPTS
OUTPUT SLAVE LATCH
ALTERNATE
FROM
FUNCTION
PERIPHERAL
OUTPUT
INPUT
BIDIRECTIONAL
ALTERNATE
FUNCTION
OUTPUT
INPUT
OUTPUT
BIDIRECTIONAL
OUTPUT MASTER LATCH
INPUT LATCH
INTERNAL DATA BUS
Figure 51. Input Configuration
Figure 52. Output Configuration
I/O PIN
I/O PIN
OPEN DRAIN
PUSH-PULL
TTL / CMOS
TTL
TRISTATE
(or Schmitt Trigger)
(or Schmitt Trigger)
TO PERIPHERAL
INPUTS AND
TO PERIPHERAL
INPUTS AND
OUTPUT SLAVE LATCH
OUTPUT SLAVE LATCH
INTERRUPTS
INTERRUPTS
OUTPUT MASTER LATCH
INPUT LATCH
OUTPUT MASTER LATCH
INPUT LATCH
INTERNAL DATA BUS
INTERNAL DATA BUS
n
n
n
92/199
9