MC908AP32CFAE Freescale Semiconductor, MC908AP32CFAE Datasheet - Page 86

• Manufacturer Part Number: MC908AP32CFAE
• Description: IC MCU 32K FLASH 8MHZ 48-LQFP
• Manufacturer: Freescale Semiconductor
• Series: HC08r

Specifications of MC908AP32CFAE

• Core Processor: HC08
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: I²C, IRSCI, SCI, SPI
• Peripherals: LED, LVD, POR, PWM
• Number Of I /o: 32
• Program Memory Size: 32KB (32K x 8)
• Program Memory Type: FLASH
• Ram Size: 2K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 48-LQFP
• Controller Family/series: HC08
• No. Of I/o's: 32
• Ram Memory Size: 2KB
• Cpu Speed: 8MHz
• No. Of Timers: 2
• Embedded Interface Type: I2C, SCI, SPI
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

Clock Generator Module (CGM)
6.3.7 Special Programming Exceptions
The programming method described in
exceptions. A value of 0 for R, N, or L is meaningless when used in the equations given. To account for
these exceptions:
(See
6.3.8 Base Clock Selector Circuit
This circuit is used to select either the oscillator clock, CGMXCLK, or the divided VCO clock, CGMPCLK,
as the source of the base clock, CGMOUT. The two input clocks go through a transition control circuit that
waits up to three CGMXCLK cycles and three CGMPCLK cycles to change from one clock source to the
other. During this time, CGMOUT is held in stasis. The output of the transition control circuit is then
divided by two to correct the duty cycle. Therefore, the bus clock frequency, which is one-half of the base
clock frequency, is one-fourth the frequency of the selected clock (CGMXCLK or CGMPCLK).
The BCS bit in the PLL control register (PCTL) selects which clock drives CGMOUT. The divided VCO
clock cannot be selected as the base clock source if the PLL is not turned on. The PLL cannot be turned
off if the divided VCO clock is selected. The PLL cannot be turned on or off simultaneously with the
selection or deselection of the divided VCO clock. The divided VCO clock also cannot be selected as the
base clock source if the factor L is programmed to a 0. This value would set up a condition inconsistent
with the operation of the PLL, so that the PLL would be disabled and the oscillator clock would be forced
as the source of the base clock.
6.3.9 CGM External Connections
In its typical configuration, the CGM requires up to four external components.
Figure 6-3
86
•
•
•
•
6.3.8 Base Clock Selector
A 0 value for R or N is interpreted exactly the same as a value of 1.
A 0 value for L disables the PLL and prevents its selection as the source for the base clock.
Bypass capacitor, C
Filter network
shows the external components for the PLL:
29.4912 MHz
19.6608 MHz
CGMVCLK
32 MHz
16 MHz
32 MHz
16 MHz
32 MHz
16 MHz
BYP
29.4912 MHz
19.6608 MHz
CGMPCLK
32 MHz
16 MHz
32 MHz
16 MHz
32 MHz
16 MHz
Circuit.)
MC68HC908AP A-Family Data Sheet, Rev. 3
Table 6-1. Numeric Examples
6.3.6 Programming the PLL
7.3728 MHz
4.9152 MHz
8.0 MHz
4.0 MHz
8.0 MHz
4.0 MHz
8.0 MHz
4.0 MHz
f
BUS
4.9152 MHz
4.9152 MHz
2 MHz
2 MHz
4 MHz
4 MHz
8 MHz
8 MHz
f
RCLK
does not account for three possible
R
1
1
1
1
1
1
1
1
10
N
8
8
4
4
2
6
4
P
0
0
0
0
0
0
0
0
Freescale Semiconductor
E
2
1
2
1
2
1
2
2
3C
40
40
40
40
40
40
27
L