MEC1404 Datasheet, PDF (486/572 Pages) Microchip Technology – Keyboard and Embedded Controller Products for Notebook PC

MEC140X/1X
41.5.3.3 Procedure to Enable the XNOR Chain
Note: The GPIO145(ICSP_CLOCK) pin is used as a clock in this test mode. This pin must never be toggled at a
rate greater than 20Mhz.
//BEGIN PROCEDURE TO ENTER XNOR CHAIN
///////////////////////////////////
// Initialize IF
///////////////////////////////////
force ICSP_MCLR = 1;
force GPIO145(ICSP_CLOCK) = 0; //TCLk
force GPIO146(ICSP_DATA) = 0; //TDI
force GPIO130/SMB03_DATA/SMB03_DATA18 = 1; //TMS
Wait 100 ns
///////////////////////////////////
// ICSP Reset
///////////////////////////////////
force ICSP_MCLR = 1;
Wait 1000 ns;
force ICSP_MCLR = 0;
///////////////////////////////////
// ICSP Bypass
///////////////////////////////////
force ICSP_MCLR = 0;
force GPIO146(ICSP_DATA) = 0; //TDI
force GPIO130/SMB03_DATA/SMB03_DATA18 = 1; //TMS
repeat (40)
begin
force ICSP_MCLR = 1;
force ICSP_MCLR = 0;
end
Wait 1000 ns
///////////////////////////////////
// Come out of reset
///////////////////////////////////
force ICSP_MCLR = 1;
force ICSP_MCLR = 0;
force ICSP_MCLR = 1;
force ICSP_MCLR = 0;
Wait 100 ns
//P 1
//P 2
DS00001956D-page 486
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