LTC1290BI LINER [Linear Technology], LTC1290BI Datasheet - Page 17

• Manufacturer Part Number: LTC1290BI
• Description: Single Chip 12-Bit Data Acquisition System
• Manufacturer: LINER [Linear Technology]

8051 Code
CONT
LOOP
DELAY
A
PPLICATI
MNEMONIC
MOV P1,#02H
CLR P1.3
SETB P1.4
MOV A,#0EH
CLR P1.4
MOV R4,#08H
NOP
MOV C,P1.1
RLC A
MOV P1.2,C
SETB P1.3
CLR P1.3
DJNZ R4,LOOP
MOV R2,A
MOV C,P1.1
CLR A
RLC A
SETB P1.3
CLR P1.3
MOV C,P1.1
RLC A
SETB P1.3
CLR P1.3
MOV C,P1.1
RLC A
SETB P1.3
CLR P1.3
MOV C, P1.1
RRC A
RRC A
RRC A
RRC A
MOV R3,A
SETB P1.3
CLR P1.3
SETB P1.4
MOV R5,#0BH
DJNZ R5,DELAY
O
U
S
Bit 1 Port 1 Set as Input
SCLK Goes Low
CS Goes High
D
CS Goes Low
Load Counter
Delay for Deglitcher
Read Data Bit Into Carry
Rotate Data Bit Into ACC
Output D
SCLK Goes High
SCLK Goes Low
Next Bit
Store MSBs in R2
Read Data Bit Into Carry
Clear ACC
Rotate Data Bit Into ACC
SCLK Goes High
SCLK Goes Low
Read Data Bit Into Carry
Rotate Data Bit Into ACC
SCLK Goes High
SCLK Goes Low
Read Data Bit Into Carry
Rotate Data Bit Into ACC
SCLK Goes High
SCLK Goes Low
Read Data Bit Into Carry
Rotate Right Into ACC
Rotate Right Into ACC
Rotate Right Into ACC
Rotate Right Into ACC
Store LSBs in R3
SCLK Goes High
SCLK Goes Low
CS Goes High
Load Counter
Go to Delay if Not Done
I FOR ATIO
IN
U
Word for LTC1290
OUTPUT PORT
Figure 5. Several LTC1290s Sharing One 3-Wire Serial Interface
2
IN
COMMENTS
SERIAL DATA
MPU
Bit to LTC1290
1
W
0
3
3
8 CHANNELS
LTC1290
U
CS
3
8 CHANNELS
LTC1290
Sharing the Serial Interface
The LTC1290 can share the same 3-wire serial interface
with other perpheral components or other LTC1290s (see
Figure 5). In this case, the CS signals decide which
LTC1290 is being addressed by the MPU.
ANALOG CONSIDERATIONS
1. Grounding
The LTC1290 should be used with an analog ground plane
and single point grounding techniques.
AGND (Pin 11) should be tied directly to this ground plane.
DGND (Pin 10) can also be tied directly to this ground
plane because minimal digital noise is generated within
the chip itself.
a 22 F tantalum with leads as short as possible. V
12) should be bypassed with a 0.1 F ceramic disk. For
single supply applications, V
plane.
It is also recommended that REF
9) be tied directly to the ground plane. All analog inputs
should be referenced directly to the single point ground.
Digital inputs and outputs should be shielded from and/or
routed away from the reference and analog circuitry.
V
CC
CS
(Pin 20) should be bypassed to the ground plane with
3
8 CHANNELS
LTC1290
CS
3-WIRE SERIAL
INTERFACE TO OTHER
PERIPHERALS OR LTC1290s
–
can be tied to the ground
–
LTC1290 F05
(Pin 13) and COM (Pin
LTC1290
17
–
(Pin