DATA SHEET
MAS 35x9F
2.11.2.1.Important Advice for Turn-on and Operat-
ing Voltage
Before the 2.2 V are programmed at the DCDC con-
verter, DSP+Codec must be enabled.
Operating and Turn-Off is possible down to 2.2 V.
The sequence should be similar to the following:
1. Start DCDC
2. Set DCDC to 2.5 V
Turn on DSP+Codec
Write App-Select memory cell
Read App-Running Mem cell
If okay: Set DCDC to 2.2 V
Set other mem cells
Set other codec registers
.....
3. Demute...send data
4. Mute...stop data.....loop "3)" "4)"...
5. Turn off DSP+Codec
goto "2)"
etc.....
The signal at pin PUP will return to low only when both
2
PUPn flags (I C subaddress 76 ) have returned to
hex
zero. Care must be taken when changing both DC/DC
output voltages to higher values. In this case, both out-
put voltages are momentarily insufficient to keep the
PUPn flags up; the resulting dip in the signal at the
PUP pin may, in turn, reset the microcontroller. To
avoid this condition, only one DC/DC output voltage
should be changed at a time. Before modifying the
second voltage, the microcontroller must wait for the
PUPn flag of the first voltage to be set again.
If only DC/DC converter 1 is used, the reference volt-
age of the second, unused converter should be set to
a lower value than that of converter 1, and its pin
VSENS2 should be connected to VDD.
The operating mode pulse width modulation, or pulse
2
frequency modulation, are controlled at I C subad-
2
dress 76 , the operating frequency at I C subad-
hex
dress 77
.
hex
Micronas
June 30, 2004; 6251-505-1DS
19
MICRONAS [ MICRONAS ]
