LTC2410 Linear Technology, LTC2410 Datasheet - Page 41

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

**********************************
* The next short loop waits for the
* LTC2410's conversion to finish before *
* starting the SPI data transfer
**********************************
*
CONVEND LDAA
*
*
*
*
*
********************
* The SPI data transfer *
********************
*
TRFLP1 LDAA
*
WAIT1
*
*
*
*
TYPICAL APPLICATIO S
ANDA
BNE
STAA
LDAA
BPL
LDAA
STAA
INX
CPX
BNE
BSET
PULA
PULY
PULX
RTS
PORTD
#%00000100
CONVEND
#$0
SPDR
SPSR
WAIT1
SPDR
0,X
#DIN4+1 Has the last byte been transferred/exchanged?
TRFLP1 If the last byte has not been reached, then proceed to the
PORTD,Y %00100000 This sets the SS* output bit to a logic high,
Load accumulator A with a null byte for SPI transfer
This writes the byte in the SPI data register and starts
the transfer
This loop waits for the SPI to complete a serial
transfer/exchange by reading the SPI Status Register
The SPIF (SPI transfer complete flag) bit is the SPSR's MSB
and is set to one at the end of an SPI transfer. The branch
will occur while SPIF is a zero.
Load accumulator A with the current byte of LTC2410 data
that was just received
Transfer the LTC2410's data to memory
Increment the pointer
next byte for transfer/exchange
de-selecting the LTC2410
Restore the A register
Restore the Y register
Restore the X register
Figure 55. This is an Example of 68HC11 Code That Captures the LTC2410’s
Conversion Results Over the SPI Serial Interface Shown in Figure 54
*
*
Retrieve the contents of port D
Look at bit 2
Bit 2 = Hi; the LTC2410's conversion is not
complete
Bit 2 = Lo; the LTC2410's conversion is complete
Branch to the loop's beginning while bit 2 remains
high
U
LTC2410
41