MC9S08QD4 Datasheet, PDF (22/202 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 2 External Signal Description
SYSTEM
POWER
+
5V
V_DD
C_{BLK +}
10 μF
V_DD
C_BY
0.1 μF
V_SS
MC9S08QD4
PORT
A
BACKGROUND HEADER
V_DD
BKGD
PTA0/KBI1P0/TPM1CH0/ADC1P0
PTA1/KBI1P1/TPM1CH1/ADC1P1
PTA2/KBI1P2/TCLK1/ADC1P2
PTA3/KBI1P3/TCLK2/ADC1P3
PTA4/TPM2CH0O/BKGD/MS
PTA5/TPM2CH0I/IRQ/RESET
I/O AND
PERIPHERAL
INTERFACE TO
APPLICATION
SYSTEM
NOTE 1
RESET
OPTIONAL
MANUAL
RESET
ASYNCHRONOUS
INTERRUPT
INPUT
IRQ
NOTE 2
NOTES:
1. RESET pin can only be used to reset into user mode, you can not enter BDM using RESET pin. BDM can
be entered by holding MS low during POR or writing a 1 to BDFR in SBDFR with MS low after issuing BDM
command.
2. IRQ has optional internal pullup/pulldown device
Figure 2-2. 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, the ADC module, and to an internal voltage regulator. The internal voltage regulator
provides 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: a bulk electrolytic
capacitor, such as a 10μF tantalum capacitor, to provide bulk charge storage for the overall system, and a
bypass capacitor, such as a 0.1μF ceramic capacitor, located as near to the MCU power pins as practical
to suppress high-frequency noise.
MC9S08QD4 Series MCU Data Sheet, Rev. 3
22
Freescale Semiconductor