EM6580SO14A EMMICRO [EM Microelectronic - MARIN SA], EM6580SO14A Datasheet - Page 46

• Manufacturer Part Number: EM6580SO14A
• Description: Ultra Low Power 8-pin Flash Microcontroller
• Manufacturer: EMMICRO [EM Microelectronic - MARIN SA]

15. RC Oscillator
The oscillator is able to generate 2 main frequencies, 800kHz and 512kHz, then through a division chain
generates the 12 possible frequencies of EM6680 chip. The frequency selection as opposed to EM6680 in
done with registers, RegMFP1.
15.1 Frequency selection
After power up the oscillator runs at 32 kHz, frequency switching is done by the software thanks to a register.
This frequency switching has to be done in a way it guarantees a proper working of the microcontroller.
RC Oscillator frequency selection. RegMFP1[3:0]
RegMFP1[3] bit selects the base frequency, 512kHz or 800kHz.
RegMFP1[2:0] bit select the frequency divider rate, 1, 2, 4, 8, 16.
When the RC frequency is changed the system clock, sysClk, has to be as close as possible to 32/50 kHz
thanks to frequency dividers.
Copyright © 2006, EM Microelectronic-Marin SA
RegMFP1[3]
Opt[7]
ExtCPUclkON
RegPresc[3]
0
0
0
0
0
1
1
1
1
1
External
Clock
RegOscTrim1
RegOscTrim2
R
[3:0]
[3:0]
RegMFP1[2]
0
1
Opt[6]
0
0
0
0
1
0
0
0
0
1
trimming
bus [7:0]
Special 4 stages divider
/2
Base frequency
RC Oscillator
selection
RegMFP1[3] RegMFP1[2:0]
/4
RegMFP1[2:0]
RegMFP1[1]
512kHz/ 800kHz
/8
Opt[5]
RC Osc.
Figure 26: Oscillator architecture
0
0
1
1
0
0
0
1
1
0
/16
Frequency divider
rate selection
frequency
RegMFP1[0]
Selected
trimmed
Opt[4]
0
1
0
1
0
0
1
0
1
0
/2
Frequency
divider
/4 /8 /16
46
frequency
Selected
divided
Frequency of RCclk
PRESCALER
LOW 15 stage divider
128.00
256.00
512.00
100.00
200.00
400.00
800.00
CPU clock frequency
32.00
64.00
50.00
Peripherals clock frequency
set at 32 or 50kHz
RCCLK
automatically
SysCLK
www.emmicroelectronic.com
EM6580
cadence all
peripherals
Unit
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
Uses to