Datasheet

21
LTC1285/LTC1288
LABEL MNEMONIC OPERAND COMMENTS
LDAA #$50 CONFIGURATION DATA FOR SPCR
STAA $1028 LOAD DATA INTO SPCR ($1028)
LDAA #$1B CONFIG. DATA FOR PORT D DDR
STAA $1009 LOAD DATA INTO PORT D DDR
LDAA #$01 LOAD DIN WORD INTO ACC A
STAA $50 LOAD DIN DATA INTO $50
LDAA #$A0 LOAD DIN WORD INTO ACC A
STAA $51 LOAD DIN DATA INTO $51
LDAA #$00 LOAD DUMMY DIN WORD INTO
ACC A
STAA $52 LOAD DUMMY DIN DATA INTO $52
LDX #$1000 LOAD INDEX REGISTER X WITH
$1000
LOOP BCLR $08,X,#$01 D0 GOES LOW (CS GOES LOW)
LDAA $50 LOAD DIN INTO ACC A FROM $50
STAA $102A LOAD DIN INTO SPI, START SCK
LDAA $1029 CHECK SPI STATUS REG
WAIT1 BPL WAIT1 CHECK IF TRANSFER IS DONE
LDAA $51 LOAD DIN INTO ACC A FROM $51
STAA $102A LOAD DIN INTO SPI, START SCK
WAIT2 LDAA $1029 CHECK SPI STATUS REG
BPL WAIT2 CHECK IF TRANSFER IS DONE
LDAA $102A LOAD LTC1288 MSBs INTO ACC A
STAA $62 STORE MSBs IN $62
LDAA $52 LOAD DUMMY INTO ACC A
FROM $52
STAA $102A LOAD DUMMY DIN INTO SPI,
START SCK
WAIT3 LDAA $1029 CHECK SPI STATUS REG
BPL WAIT3 CHECK IF TRANSFER IS DONE
BSET $08,X#$01 DO GOES HIGH (CS GOES HIGH)
LDAA $102A LOAD LTC1288 LSBs IN ACC
STAA $63 STORE LSBs IN $63
JMP LOOP START NEXT CONVERSION
LABEL MNEMONIC OPERAND COMMENTS
Timing Diagram for Interface to the MC68HC11
Hardware and Software Interface to the MC68HC11
CS
CLK
D
OUT
MPU
RECEIVED
WORD
LTC1285/88 • TA03
SGL/
DIFF
START
B3B7 B6 B5 B4 B2 B0B1B11 B10 B9 B8
D
IN
MPU
TRANSMIT
WORD
BYTE 3 (DUMMY)
BYTE 2
0000
SGL/
DIFF
1
BYTE 1
X
ODD/
SIGN
MSBF
X
X
X
X
000
X
X
X
XX
X
X
X
BYTE 3
BYTE 2
BYTE 1
B11
?
?
?
0
B10
B8
B9
B7
B6
B4
B5 B3
B2
B0
B1
DON'T CARE
ODD/
SIGN
????????

MSBF
LTC1285/88 • TA04
D
OUT
FROM LTC1298 STORED IN MC68HC11 RAM
B2 B1
B0
B3
B4
B6
B7 B5
0
0
LSB
MSB
#62
#63
0
0 B11
B10
B9 B8
CLK
D
OUT
CS
ANALOG
INPUTS
D0
SCK
MC68HC11
D
IN
MISO
LTC1288
CH0
CH1
BYTE 1
BYTE 2
MOSI
TYPICAL APPLICATIONS N
U