ST72C334N2B6 STMicroelectronics, ST72C334N2B6 Datasheet - Page 44

• Manufacturer Part Number: ST72C334N2B6
• Description: Microcontrollers (MCU) Flash 8K SPI/SCI
• Manufacturer: STMicroelectronics

Specifications of ST72C334N2B6

• Data Bus Width: 8 bit
• Program Memory Type: Flash
• Program Memory Size: 8 KB
• Data Ram Size: 384 B
• Interface Type: SCI, SPI
• Maximum Clock Frequency: 8 MHz
• Number Of Programmable I/os: 44
• Number Of Timers: 16 bit
• Operating Supply Voltage: 3.2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• Package / Case: SDIP-56
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8 bit
• Lead Free Status / Rohs Status: No

ST72334J/N, ST72314J/N, ST72124J
I/O PORTS (Cont’d)
6.1.3 I/O Port Implementation
The I/O port register configurations are summa-
rised as following.
Standard Ports
PA5:4, PC7:0, PD7:0, PE7:4, PE1:0, PF7:6, PF4
Interrupt Ports
PA2:0, PB6:4, PB2:0, PF1:0 (with pull-up)
PA3, PB7, PB3, PF2 (without pull-up)
Table 9. Port Configuration
44/125
floating input
pull-up input
open drain output
push-pull output
floating input
pull-up interrupt input
open drain output
push-pull output
floating input
floating interrupt input
open drain output
push-pull output
Port C
Port D
Port A
Port B
Port E
Port F
Port
MODE
MODE
MODE
PA7:6
PA5:4
PA3
PA2:0
PB7, PB3
PB6:4, PB2:0
PC7:0
PD7:0
PE7:4, PE1:0
PF7:6, PF4
PF2
PF1:0
Pin name
DDR
DDR
DDR
0
0
1
1
0
0
1
1
0
0
1
1
OR = 0
floating
floating
floating
floating
floating
floating
floating
floating
floating
floating
floating
OR
OR
OR
0
1
0
1
0
1
0
1
0
1
0
1
floating
Input
floating interrupt
floating interrupt
floating interrupt
pull-up interrupt
pull-up interrupt
pull-up interrupt
Switching these I/O ports from one state to anoth-
er should be done in a sequence that prevents un-
wanted side effects. Recommended safe transi-
tions are illustrated in Figure 33 Other transitions
are potentially risky and should be avoided, since
they are likely to present unwanted side-effects
such as spurious interrupt generation.
Figure 33. Interrupt I/O Port State Transition
True Open Drain Ports
PA7:6
pull-up/floating
OR = 1
floating input
open drain (high sink ports)
pull-up
pull-up
pull-up
pull-up
pull-up
interrupt
INPUT
01
(reset state)
floating
INPUT
00
MODE
open drain
open drain
open drain
open drain
open drain
open drain
open drain
open drain
open drain
open drain
open drain
OR = 0
true open-drain
open-drain
OUTPUT
Output
10
XX
= DDR, OR
push-pull
push-pull
push-pull
push-pull
push-pull
push-pull
push-pull
push-pull
push-pull
push-pull
push-pull
OR = 1
OUTPUT
push-pull
11
DDR
0
1