I found it. I didn't use PULSIN, I used COUNT. Again I had inconsistent results. Maybe you can play with COUNT duration for better results. I used an array of red, green and blue leds. Lighting up 2 or more colors like red and blue makes purple.

Count PORTA.3, 10, FREQ
IF FREQ > 9 Then BLUEGREENLED
IF FREQ > 8 Then REDLED
IF FREQ > 7 Then GREENREDLED
IF FREQ > 6 Then GREENLED 'looking FOR 600HZ
IF FREQ > 5 Then BLUELED 'LOOKING FOR 500HZ
IF FREQ > 4 Then REDLED 'LOOKING FOR 400HZ
IF FREQ > 3 Then REDBLUELED '300HZ
IF FREQ > 2 Then WHITELED '200 HZ
IF FREQ < 1 Then Pause 300
IF FREQ < 1 Then Low PORTB.0 : Low PORTB.4 : Low PORTB.7 'OFF LEDS