basic stamp

stampic

DIGITAL POTENTIOMETER

IT IS AN 8 PIN IC FROM MICROCHIP

IT CANE REPLACE THE OLD MECHANICAL

POTENTIOMETER BY A SOLID STATE IC .THAT NEVER WEAR OR BREAK OR GET

RUSTY . HIGH TEMP OR COLD have NO EFFECT. IT CANE BE SERIALLY CONTROLLED BY THE MICRO CONTROLLER IT CANE BE USED AS AN DIGITAL TO ANALOG OUT PUT FIG 2 WITH 256 STEP OF RESOLUTION 10K RESISTANCE .

THE MCP 410.10 USES AN SPI INTERFACE PRINCIPLE TO COMMUNICATE WITH THE STAMP . SPI PROTOCOL WRIGHT BITS AT THE CLOCK RISING EDGE DOING THAT FOR THE 16 BIT IT NEED TO SEND ONE COMMAND

AND THE SELECT PIN MUST BE ACTIVE LOW AT SENDING THE COMMAND THEN HIGH

AT THE END TO DESELECT THE IC .

3 PINS ONLY ARE NEEDED FROM THE STAMP TO THE MCP 410.10 FIG 1 THE CS = SELECT PIN THE CSK = THE CLOCK SIGNAL AND THE SI = THE DATA OUT PIN

TO CONTROL THE MPC410-10 YOU MUST SELECT THE IC THEN SEND THE COMMAND

17 THEN THE DESIRED VALUE FROM 0 TO 256 THAT WILL VARY THE POTENTIOMETER VALUE FROM 40 OHM TILL 10K . 10K / 256 STEP WILL GIVE ABOUT

90 OHM FOR EVERY STEP

BY USING THE ShiftOuT INSTRUCTION MOST SIGNIFICANT BIT FIRST AND THE STAMP

AFTER ASSIGNING THE ShiftOuT AND SELECT PIN AND CLOCK PIN WILL DO ALL THE JOB BY ONE SIMPLE LINE INSTRUCTION =ShiftOut SI,SCK,Msbfirst,[COMAND,RISIS ]

NOTE: BE WEAR THAT THE CURRENT FLOW MUST NOT EXCEEDS 1 mA

'http://www.oocities.org/stampic/links.htm

'SPI IS TO CONTROL THE MCP 410.10 DIGITAL POTENTIOMETER 10K FROM MICRO CHIP 2003-1-17

' THE STAMP PIN CONNECTION & THE MPC ARE THE SAME FOR CS SCK AND SI

CS CON 1 ' IC SELECT PIN OF THE MCP 410.10

SCK CON 2 ' Serial clock pin of the MCP 410.10

SI CON 3 ' Serial data OUT pin of the MCP410.10

COMAND VAR WORD

RISIS VAR WORD

COMAND = 17 'THE COMMAND TO ENABLE THE WRITING IS XX01XX01 = 17

MAIN:

FOR RISIS = 0 TO 255 ' A SIMPLE FOR NEXT LOOP