Hardware SPI with AD7680 16 bit ADC

[Castor]

I'm trying to interface the AD7680 16 bit ADC with a pic18F4685 running at 20MHZ, external osc. The timing diagram for the AD7680 is attached as a thumbnail. The shiftin command is not an option.
I'm using the 24 sclk transfer which should output the result as: 4 leading 0, 16bit result, 4 trailing 0. For that i'm using 3 variables: one, two, three. In theory the result would be:

one: 0000 xxxx
two: xxxx xxxx
three: xxxx 0000, where x is a relevant bit

DEFINE OSC 20
DEFINE LCD_DREG PORTD' Set starting Data bit (0 or 4) if 4-bit bus
DEFINE LCD_DBIT 4' Set LCD Register Select port
DEFINE LCD_RSREG PORTD' Set LCD Register Select bit
DEFINE LCD_RSBIT 0' Set LCD Enable port
DEFINE LCD_EREG PORTD' Set LCD Enable bit
DEFINE LCD_EBIT 2' Set LCD bus size (4 or 8 bits)
DEFINE LCD_BITS 4' Set number of lines on LCD
DEFINE LCD_LINES 2' Set command delay time in us
DEFINE LCD_COMMANDUS 3000' Set data delay time in us
DEFINE LCD_DATAUS 100

' -----[ Variables ]-------------------------------------------------------

led var portd.3			'led connected to portd.3
sd_mps var porte.1		'shutdown pin on the main power supply
ad_cs    	Var 	PortC.5			' ad chip select line
' -----[ Initialization ]--------------------------------------------------

adcon1=$0F	'all digital i/o
CMCON=$07		'disable comparators

trisa=%11000001		'porta HZ; except mux pins
trisb=$FF		'portb HZ
trisc=%11010111		'portc HZ; except ad lines
trisd=%00000000		'set the lcd lines as digital output
trise=%00000000		'porte output

SSPCON1=%00110000
SSPSTAT=%11000000

'variables

one		var 	byte
two 	var 	byte
three	var		byte

a_mux	var porta.1
b_mux	var porta.2
c_mux	var	porta.3
d_mux	var porta.4
inh		var porta.5

pause 2000     'lcd init
main:
high inh
lcdout $FE, 1	'clear lcd
high ad_cs
high led		'turn on running led
high sd_mps		'turn on the main power supply

low a_mux:high b_mux:low c_mux:low d_mux:low inh		'select channel 0
pauseus 10

low ad_cs		'turn on the a/d converter

SSPBUF = 0				' write to SSPBUF to start clock
PauseUs 25					'25uS fudge factor
while !SSPSTAT.0 :WEND		' while buffer empty
PauseUs 25					'25uS fudge factor
SSPSTAT.0=0
one=SSPBUF

SSPBUF = 0
PauseUs 25					'25uS fudge factor
while !SSPSTAT.0 :WEND		' while buffer empty
PauseUs 25					'25uS fudge factor
SSPSTAT.0=0
two=SSPBUF

SSPBUF = 0
PauseUs 25					'25uS fudge factor
while !SSPSTAT.0 :WEND		' while buffer empty
PauseUs 25					'25uS fudge factor
SSPSTAT.0=0
three=SSPBUF

high ad_cs			'turn off the a/d converter

high inh			'disable mux
LCDOUT $FE, $80, BIN one 'print first byte of result, first line
LCDOUT $FE, $C0, BIN two
LCDOUT $FE, $94, BIN three
pause 1000

goto main

[Castor]

If I use shiftin or a similar routine it works fine. Here is my shiftin clone. Why won't HARDWARE SPI work ?

Might it be because I connected the SPI's SDO (output) to the ADC CS line ? (see first post, first attachment)

DEFINE OSC 20
DEFINE LCD_DREG PORTD' Set starting Data bit (0 or 4) if 4-bit bus
DEFINE LCD_DBIT 4' Set LCD Register Select port
DEFINE LCD_RSREG PORTD' Set LCD Register Select bit
DEFINE LCD_RSBIT 0' Set LCD Enable port
DEFINE LCD_EREG PORTD' Set LCD Enable bit
DEFINE LCD_EBIT 2' Set LCD bus size (4 or 8 bits)
DEFINE LCD_BITS 4' Set number of lines on LCD
DEFINE LCD_LINES 2' Set command delay time in us
DEFINE LCD_COMMANDUS 3000' Set data delay time in us
DEFINE LCD_DATAUS 100

' -----[ Variables ]-------------------------------------------------------
one		var 	byte
two 	var 	byte
three	var		byte
result  var 	word

a_mux	var porta.1
b_mux	var porta.2
c_mux	var	porta.3
d_mux	var porta.4
inh		var porta.5

led var portd.3			'led connected to portd.3
sd_mps var porte.1		'shutdown pin on the main power supply


dat var portc.4
sclk var portc.3
ad_cs var portc.5			' ad chip select line

i var byte

' -----[ Initialization ]--------------------------------------------------

adcon1=$0F		'all digital i/o
CMCON=$07		'disable comparators

trisa=%11000001		'porta HZ; except mux pins

' 7 6 5 4 3 2 1 0 <= TRISA
' | | | | | | | |___________ charger control
' | | | | | | |			
' | | | | | | |_____________ MUX - A			
' | | | | | |
' | | | | | |_______________ MUX - B			
' | | | | |
' | | | | |_________________ MUX - C			
' | | | | 						
' | | | |___________________ MUX - D
' | | | 					
' | | |_____________________ MUX - INH
' | | 							
' | |_______________________ oscilator
' | 						
' |_________________________ oscilator

trisb=$FF		'portb HZ

' 7 6 5 4 3 2 1 0 <= TRISB
' | | | | | | | |___________ charger enable
' | | | | | | |			
' | | | | | | |_____________ backup battery level			
' | | | | | |
' | | | | | |_______________ CAN TXD 			
' | | | | |
' | | | | |_________________ CAN RXD			
' | | | | 						
' | | | |___________________ keyswitch
' | | | 					
' | | |_____________________ DCD - C
' | | 							
' | |_______________________ DCD - B
' | 						
' |_________________________ DCD - A

trisc=%11010111		'portc HZ; except ad lines

' 7 6 5 4 3 2 1 0 <= TRISC
' | | | | | | | |___________ capacitor enable
' | | | | | | |			
' | | | | | | |_____________ matrix switch off			
' | | | | | |
' | | | | | |_______________ DC/DC sync			
' | | | | |
' | | | | |_________________ A/D converter SCLK, SPI SCK		
' | | | | 						
' | | | |___________________ A/D converter DATA, SPI SDI
' | | | 					
' | | |_____________________ A/D converter CS,	SPI SDO
' | | 							
' | |_______________________ DCD - D
' | 						
' |_________________________ standby

trisd=%00000000		'set the lcd lines as digital output

' 7 6 5 4 3 2 1 0 <= TRISD
' | | | | | | | |___________ LCD RS
' | | | | | | |			
' | | | | | | |_____________ LCD R/W		
' | | | | | |
' | | | | | |_______________ LCD E		
' | | | | |
' | | | | |_________________ running LED/main contactor		
' | | | | 						
' | | | |___________________ LCD D4
' | | | 					
' | | |_____________________ LCD D5
' | | 							
' | |_______________________ LCD D6
' | 						
' |_________________________ LCD D7

trise=%00000000		'porte output

' 7 6 5 4 3 2 1 0 <= TRISE
' | | | | | | | |___________ buzzer
' | | | | | | |			
' | | | | | | |_____________ main power supply SD		
' | | | | | |
' | | | | | |_______________ DCD - G1, G2		
' | | | | |
' | | | | |_________________ MCLR, programmer interface		
' | | | | 						
' | | | |___________________ 0
' | | | 					
' | | |_____________________ 0
' | | 							
' | |_______________________ 0
' | 						
' |_________________________ 0


pause 2000		'LCD power up delay
main:
high inh
lcdout $FE, 1	'clear lcd
high led		'turn on running led
high sd_mps		'turn on the main power supply

low a_mux:high b_mux:low c_mux:low d_mux:low inh		'select channel 0
pauseus 100
high sclk 		'clock idles high
low ad_cs		'turn on the a/d converter

result=0									' result = 00000000 00000000
for i=0 to 7 ' output 8 clocks
one = one * 2 ' Shift each bit to the left
one = one + dat ' Data in port
pulsout sclk,5 ' Clock pulse port, 1 msec
next i

for i=0 to 7 ' output 8 clocks
two = two * 2 ' Shift each bit to the left
two = two + dat ' Data in port
pulsout sclk,5 ' Clock pulse port, 1 msec
next i

for i=0 to 7 ' output 8 clocks
three = three * 2 ' Shift each bit to the left
three = three + dat ' Data in port
pulsout sclk,5 ' Clock pulse port, 1 msec
next i

high ad_cs			' turn off the a/d converter
high inh			' disable mux

result=0									' result = 00000000 00000000
result=two									' result = 00000000 xxxxxxxx
result=result<<4							' result = 0000xxxx xxxx0000
result.highbyte=result.highbyte|one<<4		' result = xxxxxxxx xxxx0000
result.lowbyte=result.lowbyte|three>>4		' result = xxxxxxxx xxxxxxxx
											' voila, 'result' holds the 16 bit conversion result

result=result*/16							'quantisation



LCDOUT $FE, $80, BIN one 		'print first byte of result, first line
LCDOUT $FE, $C0, BIN two		'print second byte of result, first line
LCDOUT $FE, $94, BIN three		'print third byte of result, first line
LCDOUT $FE, $D4, DEC result
'must be around 2500
pause 1000


goto main

[precision]

Here is my shiftin clone.

What is shiftin clone?

.

[Castor]

it's a routine that does the same thing as the PHP shiftin function