Hello, Not sure if I can help much but it looks like shift_left should be output_bit(PS2_DATA_OUT, shift_left(&data,1,0)); data needs to be a structure or array shift needs the address of data &data Not sure about the port. Single step the program and watch for changes? I'm just starting with CCS too. If you post some more code maybe I can help. If you need SPI you should use the built in stuff very easy + lots of examples. If your rewriting PICC\Examples\EX_MOUSE.C maybe you should get that working first. http://www.ccsinfo.com/forum/ is a good place to hang out. A very good book is PICmicro MCU C by Nigel Gardner ISBN 0-9724181-0-5 Hope this helps. Pete -----Original Message----- From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu]On Behalf Of Andre Abelian Sent: Monday, November 28, 2005 7:42 PM To: Microcontroller discussion list - Public. Subject: [pic]: Problem with PortB strange Hi to all, when I set break point on portB bit 4 other pins turn on too and shift_left doesn't work I worked on it whole day and I gave up. I appreciate if any one can see what I am doing wrong. I am not sure if what I put together is real SPI interface what I wanted to do is to make spi interface. here is partial code. I am using 18f452 with mplab ccs plugin thanks Andre #include <18F252.h> #device ADC=8 #fuses HS,NOWDT,NOPROTECT,NOLVP #use delay(clock=4000000) // #use rs232(baud=1200, xmit=PIN_C6, rcv=PIN_C7,errors) // #define MICROSOFT TRUE #define MOUSE_SYSTEMS FALSE #DEFINE LEFT_BUTTON PIN_B6 #DEFINE RIGHT_BUTTON PIN_B7 #DEFINE X_CHANNEL 0 #DEFINE Y_CHANNEL 1 #define PS2_CLK_OUT PIN_B4 // #define PS2_DATA_OUT PIN_B5 // #define PS2_CLK_IN PIN_B1 // #define PS2_DATA_IN PIN_B0 // #define LED PIN_C3 void ps2_out(BYTE data) { BYTE i; output_low(PS2_CLK_OUT); // start bit on for(i=1;i<=8;++i) { output_bit(PS2_DATA_OUT, shift_left(data,1,0)); output_high(PS2_CLK_OUT); // <= I set break point here output_low(PS2_CLK_OUT); } output_low(PS2_DATA_OUT); delay_ms(11); } -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist