EM6605 EM Microelectronic, EM6605 Datasheet - Page 8

• Manufacturer Part Number: EM6605
• Description: 4 bit Microcontroller
• Manufacturer: EM Microelectronic

4. Oscillator
A built-in RC oscillator circuit generates the system operating clock ck[16] for the CPU and peripheral
circuits with the help of an externally connected resistor (between RCin and Vss) which determins the
frequency and a capacitor for better frequency stability. The oscillator circuit is supplied by the regulated
voltage, Vreg. In SLEEP mode the oscillator is stopped.
NOTE: Because the frequency can be selected by the user with an external resistor in a range from 30kHz
- 130kHz (LF range) or 100kHz - 330kHz (HF range) there is a table of corresponding frequencies for 3
different system clock frequencies. From now on besides each freq. name ck[x] there will be also an
example for 32 768 Hz system clock marked by (*f1) to indicate first - lowest frequency.
Table 6. Prescaler clock name definitions and frequency examples
buzzer frequencies for Hi frequency system clock have metal option
4.1. Prescaler
The input to the prescaler is the system clock signal.
The prescaler consists of a fifteen element divider chain
which delivers clock signals for the peripheral circuits
such as the timer/counter, buzzer, I/O debouncers and
edge detectors, as well as generating prescaler
interrupts.
The frequency of prescaler interrupts is software selectable, as shown in Table 7
© EM Microelectronic-Marin SA, 02/99, Rev. B/243
8
function
system clock
sys. clock / 2
sys. clock / 4
sys. clock / 8
sys. clock / 16
sys. clock / 32
sys. clock / 64
sys. clock / 128
sys. clock / 256
sys. clock / 512
sys. clock / 1024
sys. clock / 2048
sys. clock / 4096
sys. clock / 8192
sys. clock / 16384
sys. clock / 32768
debouncer - long
debouncer - short
cold start delay
1st buzzer freq.
2nd buzzer freq.
3rd buzzer freq.
Name
ck[16]
ck[15]
ck[14]
ck[13]
ck[12]
ck[11]
ck[10]
ck[9]
ck[8]
ck[7]
ck[6]
ck[5]
ck[4]
ck[3]
ck[2]
ck[1]
t
t
t
ck[buz1]
ck[buz2]
ck[buz3]
debL
debS
CoSt
frequency 1 (*f1)
32 768 Hz
16 348 Hz
~ 2 msec
1 024 Hz
2 048 Hz
2 667 Hz
8 192 Hz
4 096 Hz
2 048 Hz
1 024 Hz
16 msec
2 msec
512 Hz
256 Hz
128 Hz
64 Hz
32 Hz
16 Hz
8 Hz
4 Hz
2 Hz
1 Hz
frequency 2 (*f2)
Table 7.Prescaler interrupt source
8 192 / *1 024 Hz
Interrupt frequency
mask(no interrupt)
ck[1]
ck[4]
ck[6]
4 096 / *512 Hz
131 072 Hz
65 536 Hz
32 768 Hz
16 348 Hz
10 667 Hz
0.5 msec
~ 1 msec
8 192 Hz
4 096 Hz
2 048 Hz
1 024 Hz
(1Hz *f1)
(8Hz *f1)
(32Hz *f1)
4 msec
512 Hz
256 Hz
128 Hz
64 Hz
32 Hz
16 Hz
8 Hz
4 Hz
frequency 3 (*f3)
10 240/ *1 280 Hz
20 480/ *2 560 Hz
PSF1
0
0
1
1
327 680 Hz
163 480 Hz
~ 0.7 msec
26 667 Hz
81 920 Hz
40 960 Hz
20 480 Hz
10 240 Hz
EM6605
1.6 msec
0.2 msec
5 120 Hz
2 560 Hz
1 280 Hz
640 Hz
320 Hz
160 Hz
80 Hz
40 Hz
20 Hz
10 Hz
PSF0
0
1
0
1