LTC2410 Linear Technology, LTC2410 Datasheet - Page 40

• Manufacturer Part Number: LTC2410
• Description: 24-Bit No Latency ADC with Differential Input and Differential Reference
• Manufacturer: Linear Technology

LTC2410
*****************************************************
* This example program transfers the LTC2410's 32-bit output
* conversion result into four consecutive 8-bit memory locations. *
*****************************************************
*68HC11 register definition
PORTD
*
DDRD
SPSR
*
SPSR
*
SPDR
*
* RAM variables to hold the LTC2410's 32 conversion result
*
DIN1
DIN2
DIN3
DIN4
*
**********************
* Start GETDATA Routine *
**********************
*
INIT1
*
*
*DDRD's bit 5 is a 1 so that port D's SS* pin is a general output
*
*
*
*
GETDATA PSHX
*
*
*
40
TYPICAL APPLICATIO S
EQU
EQU
EQU
EQU
EQU
EQU
EQU
EQU
EQU
ORG
LDAA
STAA
LDAA
STAA
LDAA
STAA
PSHY
PSHA
LDX
LDY
BCLR
LDS
$1008
$1009
$1028
$1029
$102A
$00
$01
$02
$03
$C000
#$CFFF
#$2F
PORTD
#$38
DDRD
#$50
SPCR
#$0
#$1000
PORTD, Y %00100000
Port D data register
" – , – , SS* ,CSK ;MOSI,MISO,TxD ,RxD"
Port D data direction register
SPI control register
"SPIE,SPE ,DWOM,MSTR;SPOL,CPHA,SPR1,SPR0"
SPI status register
"SPIF,WCOL, – ,MODF; – , – , – , – "
SPI data register; Read-Buffer; Write-Shifter
This memory location holds the LTC2410's bits 31 - 24
This memory location holds the LTC2410's bits 23 - 16
This memory location holds the LTC2410's bits 15 - 08
This memory location holds the LTC2410's bits 07 - 00
Program start location
Top of C page RAM, beginning location of stack
–,–,1,0;1,1,1,1
–, –, SS*-Hi, SCK-Lo, MOSI-Hi, MISO-Hi, X, X
Keeps SS* a logic high when DDRD, bit 5 is set
–,–,1,1;1,0,0,0
SS*, SCK, MOSI are configured as Outputs
MISO, TxD, RxD are configured as Inputs
The SPI is configured as Master, CPHA = 0, CPOL = 0
and the clock rate is E/2
(This assumes an E-Clock frequency of 4MHz. For higher E-
Clock frequencies, change the above value of $50 to a value
that ensures the SCK frequency is 2MHz or less.)
The X register is used as a pointer to the memory locations
that hold the conversion data
U
This sets the SS* output bit to a logic
low, selecting the LTC2410
*