MB90480/485 Series
8. Treatment of power supply pins on models with A/D converters
Even when the A/D converters are not in use, be sure to make the necessary connections AVCC = AVRH = VCC,
and AVSS = VSS.
9. Notes on Using Power Supply
Only the MB90485 series usually uses a 3 V power supply. By setting VCC3 = 3 V power supply and VCC5 = 5 V
power supply, P20 to P27, P30 to P37, P40 to P47 and P70 to P77 can be interfaced as 5 V power supplies
separately from the main 3 V power supply. Note that the analog power supplies (such as AVCC and AVSS) for
the A/D converter can be used only as 3 V power supplies.
10. Notes on Using External Clock
Even when using an external clock signal, an oscillation stabilization delay is applied after a power-on reset or
when recovering from sub-clock or stop mode. When using an external clock, 25 MHz should be the upper
frequency limit.
The following figure shows a sample use of external clock signals.
X0
OPEN
X1
11. Treatment of NC pins
NC (internally connected) pins should always be left open.
12. Notes on during operation of PLL clock mode
On this microcontroller, if in case the crystal oscillator breaks off or an external reference clock input stops while
the PLL clock mode is selected, a self-oscillator circuit contained in the PLL may continue its operation at its
self-running frequency. However, Fujitsu will not guarantee results of operation if such failure occurs.
13. When the MB90480/485 series microcontroller is used as a single system
When the MB90480/485 series microcontroller is used as a single system, use connections so the X0A = VSS,
and X1A = Open.
14. Writing to Flash memory
For writing to Flash memory, always ensure that the operating voltage VCC is between 3.0 V and 3.6 V.
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