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ST90158 - GENERAL INFORMATION
Table 1. PLCC/PQFP Pinout Differences
1.3 I/O Port Pins
All the ports of the device can be programmed as
Input/Output or in Input mode, compatible with
TTL or CMOS levels (except where Schmitt Trig-
ger is present). Each bit can be programmed indi-
vidually (Refer to the I/O ports chapter).
TTL/CMOS Input
For all those port bits where no input schmitt trig-
ger is implemented, it is always possible to pro-
gram the input level as TTL or CMOS compatible
by programming the relevant PxC2.n control bit.
Refer I/O Ports Chapter to the section titled “Input/
Output Bit Configuration”.
Push-Pull/OD Output
The output buffer can be programmed as push-
pull or open-drain: attention must be paid to the
fact that the open-drain option corresponds only to
a disabling of P-channel MOS transistor of the
buffer itself: it is still present and physically con-
nected to the pin. Consequently it is not possible to
increase the output voltage on the pin over
VDD+0.3 Volt, to avoid direct junction biasing.
Table 2. I/O Port Characteristics
Legend: WPU = Weak Pull-Up, OD = Open Drain
PLCC
PQFP
P2.7
Pin 55
not present
P5.0
Pin 6
not present
P5.2
Pin 4
not present
P6.7
Pin 26
not present
P9.3
Pin 59
not present
HW0_SW1 (Watchdog) Not present (software watchdog only)
Pin 56 (selectable hardware or soft-
ware watchdog)
RX1CKIN
Port 9.3 (pin 59)
Port 9.4 (pin 28)
SDI
Port 7.1 (pin 65)
Port 5.1 (pin 57)
Input
Output
Weak Pull-Up
Reset State
Port 0[7:0]
TTL/CMOS
Push-Pull/OD
Yes
Bidirectional WPU
Port 1[7:0]
TTL/CMOS
Push-Pull/OD
Yes
Bidirectional WPU
Port 2[7:0]
TTL/CMOS
Push-Pull/OD
No
Bidirectional
Port 4[7:0]
Schmitt trigger
Push-Pull/OD
Yes
Bidirectional WPU
Port 5[7:0]
Schmitt trigger
Push-Pull/OD
Yes
Bidirectional WPU
Port 6[7:0]
TTL/CMOS
Push-Pull/OD
No
Bidirectional
Port 7[7:0]
Schmitt trigger
Push-Pull/OD
Yes
Bidirectional WPU
Port 8[7:0]
Schmitt trigger
Push-Pull/OD
Yes
Bidirectional WPU
Port 9[7:0]
Schmitt trigger
Push-Pull/OD
Yes
Bidirectional WPU
9