APU429 데이터 시트보기 (PDF) - APLUS INTEGRATED CIRCUITS

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APU429

4-Bit Micro-controller With LCD Driver

APLUS INTEGRATED CIRCUITS 

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

sLows.

C. Larger current load and fast clock:

a. BCF should be set to sHighs 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 shighs, 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 sLows

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

the chip’s internal power also switches between VDD1 and VDD2, which also cause a temporary power

noise.

Input pin

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

32.768kHz Xctal oscillator

Always layout the Xctal as close the Chips as possible and donct place any signals across the layout routing.

Since Xctal oscillation circuit consumes current only 0.5PA to 1PA, any power noise will disturb the oscillation.

The proper external capacitors for XIN and XOUT are necessary for the accuracy and stability of oscillation.

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

The Chipcs XOUT pin has an internal capacitor around 10~20pF connected to BAK (chipcs internal

Node).

For example:

Epsoncs C-001R 20ppm, CL=12.5pF

CIN = 25pF

COUT = 15pF

The time accuracy will be around r 0.5 second/day

Note: The parasitic capacitors of Xctal 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 IOAcs output mode by SPA instruction. Or the

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

couldn’t function properly.

Preliminary

18

Ver. 0.0

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