Datasheet

Chapter 2 Pins and Connections
MC9S08EL32 Series and MC9S08SL16 Series Data Sheet, Rev. 3
26 Freescale Semiconductor
2.2 Recommended System Connections
Figure 2-3 shows pin connections that are common to MC9S08EL32 Series and MC9S08SL16 Series
application systems.
Figure 2-3. Basic System Connections
2.2.1 Power
V
DD
and V
SS
are the primary power supply pins for the MCU. This voltage source supplies power to all
I/O buffer circuitry and to an internal voltage regulator. The internal voltage regulator provides a regulated
lower-voltage source to the CPU and other internal circuitry of the MCU.
Typically, application systems have two separate capacitors across the power pins. In this case, there
should be a bulk electrolytic capacitor, such as a 10-μF tantalum capacitor, to provide bulk charge storage
for the overall system and a 0.1-μF ceramic bypass capacitor located as near to the MCU power pins as
practical to suppress high-frequency noise. Each pin must have a bypass capacitor for best noise
suppression.
V
DDA
and V
SSA
are the analog power supply pins for the MCU. This voltage source supplies power to the
ADC module. A 0.1-μF ceramic bypass capacitor should be located as near to the MCU power pins as
practical to suppress high-frequency noise. The V
REFH
and V
REFL
pins are the voltage reference high and
voltage reference low inputs, respectively, for the ADC module.
BKGD/MS
RESET
Optional
Manual Reset
V
DD
Background Header
System
Power
PORT
B
PTB0/PIB0/SLRxD/RxD/ADP4
PTB1/PIB1/SLTxD/TxD/ADP5
PTB2/PIB2/SDA/SPSCK/ADP6
PTB3/PIB3/SCL/MOSI/ADP7
PTB4/TPM2CH1/MISO2
PTB5/TPM1CH1/SS
PTB6/SDA/XTAL
PTB7/SCL/EXTAL
PORT
C
PTC0/PIC0/TPM1CH0/ADP8
PTC1/PIC1/TPM1CH1/ADP9
PTC2/PIC2/TPM1CH2/ADP10
PTC3/PIC3/TPM1CH3/ADP11
PTC4/PIC4/ADP12
PTC5/PIC5/ACMP2O/ADP13
PTC6/PIC6/ACMP2+/ADP14
MC9S08EL32
V
DDA
/V
REFH
V
SSA
/V
REFL
V
SS
V
DD
PTC7/PIC7/ACMP2–/ADP15
C
BY
0.1 μF
C
BLK
10 μF
+
5 V
+
C2
C1
X1
R
F
R
S
PORT
A
PTA0/PIA0/TPM1CH0/TCLK/ACMP1+/ADP0
PTA1/PIA1/TPM2CH0/ACMP1–/ADP1
PTA2/PIA2/SDA/RxD/ACMP1O/ADP2
PTA3/PIA3/SCL/TxD/ADP3
PTA6/TPM2CH0
PTA7/TPM2CH1
V
DD
4.7 kΩ–10 kΩ
0.1 μF
R
PU
R
PU
C
BY
0.1 μF