4 mhz program speed in pic 18f4550 please

[mackrackit]

but max6675 demand 4,3 mhz max to have the correct communication

Nope, the 6675 will work just fine with a MCU running at 48MHz.

Here are some snippets.

DEFINE OSC 48
@ __CONFIG   _CONFIG1L, _PLLDIV_1_1L & _CPUDIV_OSC1_PLL2_1L & _USBDIV_2_1L
@ __CONFIG   _CONFIG1H, _FOSC_HSPLL_HS_1H
@ __CONFIG    _CONFIG2H, _WDT_OFF_2H & _WDTPS_512_2H
@ __CONFIG    _CONFIG3H, _PBADEN_OFF_3H & _MCLRE_OFF_3H 
@ __CONFIG    _CONFIG4L, _LVP_OFF_4L & _ICPRT_OFF_4L &_XINST_OFF_4L 

'Alias pins - MAX6675 temp sensor
MXSCLK  VAR     PORTA.0   'Clock
MXCS    VAR     PORTA.1    'Chip Select
MXSO    VAR     PORTA.2   'Serial out


'Read the 6675
MXCS = 0  'Chip select low
shiftin MXSO, MXSCLK, 0, [MXTemp\16]   'read the data to MXTemp
MXCS = 1    'Chip select high
TempC = MXtemp >> 5   'right shift the data 5 places to get degrees C (Read the Data sheet)
TempF = ABS(TempC) */ 461
TempF = TempF + 32

I also deleted your other post as it is a duplicate of this one. No need to double post.