B. Ag and Li battery mode applications:

After Power on, Reset or release from STOP mode. Need to wait 2 seconds long, then can set BCF to

Low .

C. Larger current load and fast clock:

a. BCF should be set to High for the case of fast clock or larger current load (such as RFC, ADC,

DAC, EL-light and Buzzer output) use.

b. After set BCF to high , need wait 2 ms long at least, then can enable larger current load. Or after

disable Larger current load, need wait 2ms long at least, then can set BCF to Low

D. Li battery mode applications:

Especially for Li battery mode, BCF switching will cause a temporary current surge (or power noise) on

BAK. Furthermore if not necessary, don’t switch BCF too often as possible.

E. Improperly use of BCF will cause malfunction to chips.

F. Lower current consumption and reliability:

The chip’s reliability will greatly decrease if invalid use BCF, especially for Li-battery mode. Because

noise.

Input pin

Any input pins floating will cause chips in malfunction and large current consumption.

32.768kHz X tal oscillator

Always layout the X tal as close the Chips as possible and don t place any signals across the layout routing.

Since X tal oscillation circuit consumes current only 0.5 A to 1 A, any power noise will disturb the oscillation.

1 / (Cin+Cpcb) + 1 / (Cout+Cpcb ) = 1/CL

Node).

For example:

Epson s C-001R 20ppm, CL=12.5pF

The time accuracy will be around 0.5 second/day

Note: The parasitic capacitors of X tal pins in PCB layout need be considered in above calculation.

RFC/Event counter/IOA for

APU429

If anyone uses RFC / Event counter function and IOAs in the same application, make sure the pin IOA1

(which is corresponding to CX by mask option) must set as IOA s output mode by SPA instruction. Or the

signal changes on CX pin may cause HALT release or interrupt for IOA s port. In this case the program

couldn’t function properly.

Preliminary

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