MC68HC908LB8CPE Freescale Semiconductor, MC68HC908LB8CPE Datasheet - Page 131

• Manufacturer Part Number: MC68HC908LB8CPE
• Description: IC MCU 8K FLASH 8MHZ 20DIP
• Manufacturer: Freescale Semiconductor
• Series: HC08r

Specifications of MC68HC908LB8CPE

• Core Processor: HC08
• Core Size: 8-Bit
• Speed: 8MHz
• Peripherals: LVR, POR, PWM
• Number Of I /o: 18
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 7x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Connectivity: -

ECGST — External Clock Status Bit
13.8.2 Oscillator Trim Register (OSCTRIM)
TRIM7–TRIM0 — Internal Oscillator Trim Factor Bits
Freescale Semiconductor
This read-only bit indicates whether or not an external clock source is engaged to drive the system
clock.
These read/write bits change the size of the internal capacitor used by the internal oscillator. By
measuring the period of the internal clock and adjusting this factor accordingly, the frequency of the
internal clock can be fine tuned. Increasing (decreasing) this factor by one increases (decreases) the
period by appoximately 0.2% of the untrimmed period (the period for TRIM = $80). The trimmed
frequency is guaranteed not to vary by more than ±5% over the full specified range of temperature and
voltage. The reset value is $80, which sets the frequency to 16 MHz (4.0 MHz bus speed) ±25%.
1 = An external clock source engaged
0 = An external clock source disengaged
Address: $0038
Reset:
Read:
Write:
TRIM7
Bit 7
1
Figure 13-5. Oscillator Trim Register (OSCTRIM)
TRIM6
6
0
MC68HC908LB8 Data Sheet, Rev. 1
TRIM5
5
0
TRIM4
4
0
TRIM3
3
0
TRIM2
2
0
TRIM1
1
0
Input/Output (I/O) Registers
TRIM0
Bit 0
0
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