DA6505.005
11 June 2018
CLOCK OSCILLATOR FREQUENCY TRIM REGISTER (FF/7FHEX
)
Note that the internal clock oscillator frequency has
been factory trimmed and the trim value has been
stored into the EEPROM (BF/3FHEX). It is
recommended not to change the factory
programmed value! See table 11.
measured at the SDO pin and also adjusted by the
Clock oscillator frequency trim register.
The seven LSB bits adjust the oscillator signal period
in 35 ns steps. The signal period decreases and
frequency increases when the trim value increases.
The seven bits register value is considered as a 2’s
complement number. Typically the mid value 00HEX
corresponds to 212 kHz clock oscillator frequency.
The Clock oscillator frequency trim register
(FF/7FHEX) is for trimming the internal clock oscillator
to 250 kHz frequency. By selecting ENTP=1 in the
Clock oscillator frequency trim register (FF/7FHEX
)
After finding a suitable trim value it can be stored into
the EEPROM (BF/3FHEX).
and STEST=0001 and TRIM=11 in the Trim and test
register (FA/7AHEX) the internal oscillator is turned on
all the time and the 250 kHz oscillator signal can be
Table 11. Clock oscillator frequency trim register (FF/7FHEX
)
Bit
Bit
Description
Value
(bin)
Value
(2’s complement)
Value Function
(dec)
Number Name
7
ENTP
0
1
Disable test pin (default)
SDO is test pin if STEST<>0
Enable for
test pin
6-0
OSCF
Clock
0111111
0111110
…….
0000001
0000000
1111111
1111110
…….
63
62
…
1
0
-1
63
62
…
1
0
127
126
…
65
64
Max frequency
…
…
…
212 kHz
…
…
…
oscillator
frequency
control
-2
…
-63
-64
1000001
1000000
…
Min frequency
26 (44)
MAS [ MICRO ANALOG SYSTEMS ]
