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7/140
Figure 5. 24-Pin SO Package Pinout
RESET (see Note 1): Bidirectional. This active low
signal forces the initialization of the MCU. This
event is the top priority non maskable interrupt.
This pin is switched low when the Watchdog is trig-
gered or the VDD is low. It can be used to reset ex-
ternal peripherals.
OSCIN/OSCOUT: Input/Output Oscillator pin.
These pins connect a parallel-resonant crystal, or
an external source, to the on-chip oscillator.
VDD/VSS (see Note 2): Main Power Supply and
Ground voltages.
VDDA/VSSA (see Note 2): Power Supply and
Ground voltages for analog peripherals.
Alternate Functions: Several pins of the I/O ports
assume software programmable alternate func-
tions as shown in the pin description.
Note 1: Adding two 100 nF decoupling capacitors
on the Reset pin (respectively connected to V
DD
and V
SS) will significantly improve product electro-
magnetic susceptibility performance.
Note 2: To enhance the reliability of operation, it is
recommended that VDDA and VDD be connected to-
gether on the application board. This also applies
to VSSA and VSS.
Note 3: The USBOE alternate function is mapped
on Port C2 in 32/34/48 pin devices. In SO24 devic-
es it is mapped on Port B1.
Note 4: The timer OCMP1 alternate function is
mapped on Port A6 in 32/34/48 pin devices. In
SO24 devices it is not available.
Table 2. Device Pin Description (TQFP48, SO34 and SDIP32)
14
13
11
12
15
16
17
18
PA2(25mA)/SCL/ICCCLK
PA1(25mA)/SDA/ICCDATA
PA0/MCO
VSSA
PA7/OCMP2/IT4
PA5/ICAP2/IT2
PA4/ICAP1/IT1
1
2
3
4
5
6
7
8
9
10
VDD
RDI/PC0
TDO/PC1
VSS
PA3/EXTCLK
IT7/PB6(10mA)
19
20
VPP/TEST
PB3(10mA)
PB2(10mA)
USBDP
RESET/
OSCOUT
USBOE/PB1(10mA)
PB0(10mA)
OSCIN
21
22
23
24
USBDM
USBVcc
Pin n°
Pin Name
Type
Level
Port / Control
Main
Function
(after
reset)
Alternate Function
SDIP32
SO34
TQFP48
Inpu
t
O
u
tput
Input
Output
fl
oat
wpu
int
ana
OD
PP
116
VDD
S
Power supply voltage (4V - 5.5V)
2
7
OSCOUT
O
Oscillator output
3
8
OSCIN
I
Oscillator input
449
VSS
S
Digital ground
5
10 PC2/USBOE
I/O
CT
X
X
Port C2
USB Output Enable
6
13 PC1/TDO
I/O
CT
X
X
Port C1
SCI Transmit Data Out-
put
7
14 PC0/RDI
I/O CT
X
X
Port C0
SCI Receive Data Input
8
15 RESET
I/O
X
X
Reset