MC1321x Introduction
MC1321x Reference Manual, Rev. 1.6
1-16
Freescale Semiconductor
•
ICGLCLK — Development tools can select this internal self-clocked source (~ 8 MHz) to speed
up BDC communications in systems where the bus clock is slow
•
ICGERCLK — External reference clock can be selected as the real-time interrupt clock source
The MCU ICG is described in detail by
Chapter 14, “MCU Internal Clock Generator (ICG)”
.
1.9
System Clock Configuration
The MC1321x provides several options for the system clock configuration. The modem requires a 16MHz
crystal for its source oscillator and can also supply a selectable frequency clock out (CLKO). The CLKO
frequency can be programmed for 16 MHz, 8 MHz, 4 MHz, 2 MHz, 1 MHz, 62.5 kHz, 32.786+ kHz
(default), or 16.393+ kHz. The MCU can use a second crystal if desired or it can derive its external clock
source from the modem CLKO as shown in
. The MCU also has an internal clock generator
that can be used for start-up and when the modem is shutdown (for lowest power). The MCU internal
reference is approximately 243 kHz.
Figure 1-10. MC1321x Single Clock
8 0 2 .1 5 .4 M O D E M
H C S 0 8 M C U
X T A L 1
X T A L 2
C L K O
E X T A L
X T A L
M C 1 3 2 1 X
2 7
2 8
1 0
9
8
1 6 M H z
Содержание freescale semiconductor MC13211
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Страница 100: ...MC1321x Serial Peripheral Interface SPI MC1321x Reference Manual Rev 1 6 4 24 Freescale Semiconductor...
Страница 166: ...Modem Modes of Operation MC1321x Reference Manual Rev 1 6 7 22 Freescale Semiconductor...
Страница 172: ...Modem Interrupt Description MC1321x Reference Manual Rev 1 6 8 6 Freescale Semiconductor...
Страница 186: ...MCU Modes of Operation MC1321x Reference Manual Rev 1 6 10 8 Freescale Semiconductor...
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Страница 338: ...Inter Integrated Circuit IIC MC1321x Reference Manual Rev 1 6 19 14 Freescale Semiconductor...
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