st2608b Sitronix Technology Corporation, st2608b Datasheet - Page 30

• Manufacturer Part Number: st2608b
• Description: 8-bit Integrated Microcontroller
• Manufacturer: Sitronix Technology Corporation

< IrDA BGRCK generation source >
BGRCK can be generated by two ways.
1. When bit7 of BCTR is 0,Haredware PLL which is used to stable BGRCK output will be operated. Cause
2. When bit7 of BCTR is 1:
It’ s used when OSC is X’ tal. Since X’ tal can produce stable frequency, and BGRCK comes from OSC, so
BGRCK will also be stable if OSC is X’ tal. Programmer can get better BGRCK output to make UART signal
much more accurate by this way.
When bit7 of BCTR is 1, UART baud rate will be get in the following formula:
baud rate = Sysclk/(BDIV*16) (no need to set “BRS”)
< How to avoid LCD blink caused by PSG >
Description:
LCD display may blink when LCD function and PSG function are playing in the same time. LCD blink caused by CPU can ’ t
stand the load of calculation. So the LCD display my lag. And We can find there has blink problem.
Solution:
By using internal DMA function to move LCD data instead of programming method can solve part of this kind of problem. If
there still has the same problem, we can separate LCD data into 16 parts and use DMA method to move into LCD RAM. The
LCD blink problem can be totally solved.
Example program can be found by SA engineer. !!Please email us!!!
< How to measure the internal current of ST2600B?>
When finish developing program by ST2600B, programmer should measure the current consumption of totally possible
situations. In that time programmer can use ST2600B stand alone mode with running external ROM. In order to only measure
the current from IC, the power for External ROM should be independent. And then we can measure the current from IC only!!
< Ways to save power consumption >
There are some factors which can effect current consumption…
(1) Main-frequency : Higher frequency needs more current
(2) DAC mode cost much current than PWM mode
(3) Vlcd voltage level : Higher Vlcd pays higher current.
(4) Using EPROM will cost more current than no use.
(5) Input without any connection will randomly cost power
(6) WAIT mode with considerable program can save lots of power
(7) Larger panel will pay more current.
(8) Un-ideal hardware connection will cause unknown current waste.
BGRCK comes from OSC, since RC-OSC can’ t produce stable frequency, ST26xx hardware will fine tune
BGRCK output frequency referenced from 32768Hz crystal to make BGRCK is in the range no matter VDD
variation.
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ST2608B