LTC1093 Ver la hoja de datos (PDF) - Linear Technology
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LTC1093 Datasheet PDF : 32 Pages
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LTC1091/LTC1092
LTC1093/LTC1094
APPLICATI S I FOR ATIO
Interfacing to the Parallel Port of the
Intel 8051 Family
The Intel 8051 has been chosen to demonstrate the
interface between the LTC1091 and parallel port micro-
processors. Normally, the CS, SCLK and DIN signals
would be generated on three port lines and the DOUT signal
read on a 4th port line. This works very well. However, we
will demonstrate here an interface with the DIN and DOUT
of the LTC1091 tied together as described in section 4.
This saves one wire.
The 8051 first sends the start bit and MUX address to the
LTC1091 over the data line connected to P1.2. Then P1.2
is reconfigured as an input (by writing to it a one) and the
8051 reads back the 10-bit A/D result over the same data
line.
ANALOG
INPUTS
CS
CLK
LTC1091
DOUT
DIN
P1.4
P1.3
8051
P1.2
MUX ADDRESS
A/D RESULT
1091-4 AI17
DOUT from LTC1091 Stored in 8051 RAM
MSB
R2 B9 B8 B7 B6 B5 B4 B3 B2
LSB
R3 B1 B0 0 0 0 0 0 0
LABEL MNEMONIC OPERAND COMMENTS
MOV
SETB
CLR
MOV
LOOP 1 RLC
CLR
MOV
SETB
DJNZ
MOV
CLR
MOV
LOOP MOV
RLC
SETB
CLR
DJNZ
MOV
MOV
SETB
CLR
CLR
RLC
MOV
RRC
RRC
MOV
SETB
A, #FFH
P1.4
P1.4
R4, #04
A
P1.3
P1.2, C
P1.3
R4, LOOP 1
P1, #04
P1.3
R4, #09
C, P1.2
A
P1.3
P1.3
R4, LOOP
R2, A
C, P1.2
P1.3
P1.3
A
A
C, P1.2
A
A
R3, A
P1.4
DIN Word for LTC1091
Make Sure CS Is High
CS Goes Low
Load Counter
Rotate DIN Bit into Carry
SCLK Goes Low
Output DIN Bit to LTC1091
SCLK Goes High
Next Bit
Bit 2 Becomes an Input
SCLK Goes Low
Load Counter
Read Data Bit into Carry
Rotate Data Bit into Acc
SCLK Goes High
SCLK Goes Low
Next Bit
Store MSBs in R2
Read Data Bit into Carry
SCLK Goes High
SCLK Goes Low
Clear Acc
Rotate Data Bit from Carry to Acc
Read Data Bit into Carry
Rotate Right into Acc
Rotate Right into Acc
Store LSBs in R3
CS Goes High
MSBF BIT
LATCHED
INTO LTC1091
CS
1
2
3
4
CLK
DATA (DIN/DOUT)
START
SGL/ ODD/
DIFF SIGN MSBF
8051 P1.2 OUTPUTS
DATA TO LTC1091
8051 P1.2 RECONFIGURED AS AN
INPUT AFTER THE 4TH RISING CLK
AND BEFORE THE 4TH FALLING CLK
B9
B8
B7
B6
B5
B4
B3
B2
B1
B0
LTC1091 SENDS A/D RESULT
BACK TO 8051 P1.2
LTC1091 TAKES CONTROL OF DATA LINE
ON 4TH FALLING CLK
1091/2/3/4 AI18
19
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