LTC1291 Linear Technology, LTC1291 Datasheet - Page 13

• Manufacturer Part Number: LTC1291
• Description: Single Chip 12-Bit Data Acquisition System
• Manufacturer: Linear Technology

A
8051 Code
In this example the input MUX is configured to accept a
differential input between CH0 and CH1. The result from
the conversion is clocked out MSB-first.
LABEL MNEMONIC
CONT
LOOP1 RLC
LOOP
Sharing the Serial Interface
The LTC1291 can share the same 3-wire serial interface
with other peripheral components or other LTC1291s
PPLICATI
SETB
MOV
CLR
MOV
CLR
MOV
SETB
DJNZ
MOV
CLR
MOV
MOV
RLC
SETB
CLR
DJNZ
MOV
MOV
SETB
O
OPERAND
P1.4
A,#98H
P1.4
R4,#05H
A
P1.3
P1.2,C
P1.3
R4,LOOP1
P1,#04H
P1.3
R4,#09H
C,P1.2
A
P1.3
P1.3
R4,LOOP
R2,A
C,P1.2
P1.3
U
S
I FOR ATIO
U
CS GOES HIGH
DIN WORD FOR LTC1291
CS GOES LOW
LOAD COUNTER
ROTATE DIN BIT INTO CARRY
CLK GOES LOW
OUTPUT DIN BIT TO LTC1291
CLK GOES HIGH
NEXT DIN BIT
P1.2 BECOMES AN INPUT
CLK GOES LOW
LOAD COUNTER
READ DATA BIT INTO CARRY
ROTATE DATA BIT (B3) INTO ACC
CLK GOES HIGH
CLK GOES LOW
STORE MSBS IN R2
READ DATA BIT INTO CARRY
CLK GOES HIGH
COMMENTS
NEXT DOUT BIT
OUTPUT PORT
Figure 3. Several LTC1291s Sharing One 3-Wire Serial Interface
2
SERIAL DATA
MPU
1
W
0
3
3
2 CHANNELS
LTC1291
U
CS
3
2 CHANNELS
LTC1291
LABEL MNEMONIC
(Figure 3). The CS signals decide which LTC1291 is being
addressed by MPU.
CS
CLR
CLR
RLC
MOV
RLC
SETB
CLR
MOV
RLC
SETB
CLR
MOV
SETB
RRC
RRC
RRC
RRC
MOV
AJMP
3
2 CHANNELS
LTC1291
CS
OPERAND
P1.3
A
A
C,P1.2
A
P1.3
P1.3
C,P1.2
A
P1.3
P1.3
C,P1.2
P1.4
A
A
A
A
R3,A
CONT
3-WIRE SERIAL
INTERFACE TO OTHER
PERIPHERALS OR LTC1291s
COMMENTS
CLK GOES LOW
CLEAR ACC
ROTATE DATA BIT (B3) INTO ACC
READ DATA BIT INTO CARRY
ROTATE DATA BIT (B2) INTO ACC
CLK GOES HIGH
CLK GOES LOW
READ DATA BIT INTO CARRY
ROTATE DATA BIT (B1) INTO ACC
CLK GOES HIGH
CLK GOES LOW
READ DATA BIT INTO CARRY
CS GOES HIGH
ROTATE DATA BIT (B0) INTO ACC
ROTAGE RIGHT INTO ACC
ROTAGE RIGHT INTO ACC
ROTAGE RIGHT INTO ACC
STORE LSBs IN R3
START NEXT CONVERSION
LTC1291 F03
LTC1291
13