In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Beau Schwabe wrote:

<SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana">Electronegativity,
<SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana"> 

<SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana">Do you really want the LED's to be that bright?  There are some very impressive 2mA LED's that put out lots of light.

<SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana"> 

<SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana"> 

<SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana">Anyway, there are some other ways to reduce the amount of current without any external parts, by making use of

<SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana">the internal RC oscillator settings of the SX you can have dramatic results.

<SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana"> 

<SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana">I did not have a SX20, but I did have a SX28.  The datasheet indicates that they should be the same.

<SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana"> 

<SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana">Here is the DATA I obtained by placing a 10 Ohm resistor in series with the power to the SX and measuring the voltage

<SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana">across the resistor.

<SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana"><SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana"> 

<SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana">
[code]

<SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana">50MHz resonator -      0.538V = 53.8mA 

<SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana">--------------------------------------

<SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana">4Mhz internal RC -      0.068V =   6.8mA

<SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana">1Mhz internal RC -      0.028V =   2.8mA

<SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana">128KHz internal RC -   0.015V =   1.5mA

<SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana"> 32KHz internal RC -    0.014V =   1.3mA

<SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana"> 

<SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana">The program was just a simple program to toggle one of the I/O pins at 1/10th the clock frequency.

<SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana"> <SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Verdana">


[code]
Tris_A = %00000000   'Make ALL pins on PortA output   This is because we just don't want any pins to float. 


Tris_B = %00000000   'Make ALL pins on PortB output   Floating pins EAT current.  


Tris_C = %00000000   'Make ALL pins on PortC output  

Asm 

  

Main: 

     MOV RB.0,#1     '2 Clocks 

     NOP             '1 Clock 

     NOP             '1 Clock  

     NOP             '1 Clock     (5) Clocks "ON" 


     MOV RB.0,#0     '2 Clocks 

     JMP Main        '3 Clocks    (5) Clocks "OFF"

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