Datasheet
Table Of Contents
- List of Sections
- Table of Contents
- List of Figures
- List of Tables
- Section 1. General Description
- 1.1 Contents
- 1.2 Introduction
- 1.3 Features
- 1.4 MCU Block Diagram
- 1.5 Pin Assignments
- 1.6 Pin Functions
- 1.6.1 Power Supply Pins (Vdd and Vss)
- 1.6.2 Oscillator Pins (OSC1 and OSC2)
- 1.6.3 External Reset Pin (RST)
- 1.6.4 External Interrupt Pin (IRQ)
- 1.6.5 Analog Power Supply Pin (VDDA)
- 1.6.6 Analog Ground Pin (VSSA)
- 1.6.7 Analog Ground Pin (AVSS/VREFL)
- 1.6.8 ADC Voltage Reference Pin (VREFH)
- 1.6.9 Analog Supply Pin (VDDAREF)
- 1.6.10 External Filter Capacitor Pin (CGMXFC)
- 1.6.11 Port A Input/Output (I/O) Pins (PTA7-PTA0)
- 1.6.12 Port B I/O Pins (PTB7/ATD7-PTB0/ATD0)
- 1.6.13 Port C I/O Pins (PTC5-PTC0)
- 1.6.14 Port D I/O Pins (PTD7-PTD0)
- 1.6.15 Port E I/O Pins (PTE7/SPSCK-PTE0/TxD)
- 1.6.16 Port F I/O Pins (PTF7-PTF0/TACH2)
- 1.6.17 Port G I/O Pins (PTG2/KBD2-PTG0/KBD0)
- 1.6.18 Port H I/O Pins (PTH1/KBD4-PTH0/KBD3)
- 1.7 I/O Pin Summary
- 1.8 Signal Name Conventions
- 1.9 Clock Source Summary
- Section 2. Memory Map
- Section 3. Random-Access Memory (RAM)
- Section 4. FLASH Memory
- Section 5. EEPROM
- Section 6. Configuration Register (CONFIG)
- Section 7. Central Processor Unit (CPU)
- Section 8. System Integration Module (SIM)
- Section 9. Clock Generator Module (CGM)
- 9.1 Contents
- 9.2 Introduction
- 9.3 Features
- 9.4 Functional Description
- 9.5 I/O Signals
- 9.5.1 Crystal Amplifier Input Pin (OSC1)
- 9.5.2 Crystal Amplifier Output Pin (OSC2)
- 9.5.3 External Filter Capacitor Pin (CGMXFC)
- 9.5.4 PLL Analog Power Pin (VDDA)
- 9.5.5 Oscillator Enable Signal (SIMOSCEN)
- 9.5.6 Crystal Output Frequency Signal (CGMXCLK)
- 9.5.7 CGM Base Clock Output (CGMOUT)
- 9.5.8 CGM CPU Interrupt (CGMINT)
- 9.6 CGM Registers
- 9.7 Interrupts
- 9.8 Low-Power Modes
- 9.9 CGM During Break Interrupts
- 9.10 Acquisition/Lock Time Specifications
- Section 10. Monitor ROM (MON)
- Section 11. Timer Interface Module A (TIMA)
- Section 12. Timer Interface Module B (TIMB)
- Section 13. Programmable Interrupt Timer (PIT)
- Section 14. Analog-to-Digital Converter (ADC)
- Section 15. Serial Communications Interface Module (SCI)
- Section 16. Serial Peripheral Interface Module (SPI)
- 16.1 Contents
- 16.2 Introduction
- 16.3 Features
- 16.4 Pin Name Conventions and I/O Register Addresses
- 16.5 Functional Description
- 16.6 Transmission Formats
- 16.7 Queuing Transmission Data
- 16.8 Error Conditions
- 16.9 Interrupts
- 16.10 Resetting the SPI
- 16.11 Low-Power Modes
- 16.12 SPI During Break Interrupts
- 16.13 I/O Signals
- 16.14 I/O Registers
- Section 17. Input/Output (I/O) Ports
- Section 18. External Interrupt (IRQ)
- Section 19. Keyboard Interrupt Module (KBI)
- Section 20. Computer Operating Properly (COP)
- Section 21. Low-Voltage Inhibit (LVI)
- Section 22. Break Module (BRK)
- Section 23. Electrical Specifications
- 23.1 Contents
- 23.2 Introduction
- 23.3 Absolute Maximum Ratings
- 23.4 Functional Operating Range
- 23.5 Thermal Characteristics
- 23.6 5.0-V DC Electrical Characteristics
- 23.7 EEPROM and Memory Characteristics
- 23.8 5.0-V Control Timing
- 23.9 Timer Interface Module Characteristics
- 23.10 ADC Characteristics
- 23.11 SPI Characteristics
- 23.12 Clock Generation Module Characteristics
- 23.13 FLASH Memory Characteristics
- Section 24. Mechanical Specifications
- Section 25. Ordering Information
Clock Generator Module (CGM)
MC68HC908AB32 — Rev. 1.1 Technical Data
Freescale Semiconductor Clock Generator Module (CGM)
141
• Crystal, X
1
• Fixed capacitor, C
1
• Tuning capacitor, C
2
(can also be a fixed capacitor)
• Feedback resistor, R
B
• Series resistor, R
S
(optional)
The series resistor (R
S
) is included in the diagram to follow strict Pierce
oscillator guidelines and may not be required for all ranges of operation,
especially with high frequency crystals. Refer to the crystal
manufacturer’s data for more information.
Figure 9-3 also shows the external components for the PLL:
• Bypass capacitor, C
BYP
• Filter capacitor, C
F
Care should be taken with routing in order to minimize signal cross talk
and noise. (See 9.10 Acquisition/Lock Time Specifications for routing
information and more information on the filter capacitor’s value and its
effects on PLL performance).
Figure 9-3. CGM External Connections
C
1
C
2
C
F
SIMOSCEN
CGMXCLK
R
B
X
1
R
S
*
C
BYP
*R
S
can be zero (shorted) when used with higher-frequency crystals. Refer to manufacturer’s data.
OSC1 OSC2 V
SSA
CGMXFC V
DDA
V
DD
