Shiftin problem (16f877A with MCP3201)

[Darrel Taylor]

I think you need mode 4 in the SHIFTIN.
And it needs to shift 16 bits, not 12. Even though it's a 12-bit result.

A few other changes and ... try this ...

#HEADER
    ERRORLEVEL -306			; SUPRESS PAGE BOUNDRY ERROR
#ENDHEADER

#CONFIG
    __CONFIG _XT_OSC & _WDT_OFF & _LVP_OFF & _CPD_ON & _CP_ALL & _PWRTE_ON & _BODEN_ON
#ENDCONFIG

DEFINE DEBUGIN_REG	PORTC
DEFINE DEBUGIN_BIT	7
DEFINE DEBUG_REG	PORTC
DEFINE DEBUG_BIT	6
DEFINE DEBUG_BAUD	2400
DEFINE DEBUG_MODE	1

'-- MCP3201 pins
CLK	  Var PortE.0
DIN   Var PortE.1
CS	  Var PortE.2

'-------------------
Calibration  CON -1            ; Signed value in 0.1 deg. C
Sensor       VAR WORD

'-------------------
ADCON1 = 7
CMCON = 7
HIGH CS

Main:
    LOW CS
    SHIFTIN Din,Clk,4,[Sensor\16]
    HIGH CS

    Sensor = (Sensor & $FFF) * 5000
    Sensor = DIV32 4095 + Calibration
    IF Sensor <= 1500 THEN DEBUG DEC Sensor/10,".",DEC1 Sensor,13,10
    PAUSE 1000
Goto Main