LTC1290_15 Datasheet, PDF (16/32 Pages) Linear Technology – Single Chip 12-Bit Data Acquisition System

LTC1290
APPLICATI S I FOR ATIO
Table 2. Microprocessors with Hardware Serial Interfaces
Compatible with the LTC1290**
PART NUMBER
TYPE OF INTERFACE
Motorola
MC6805S2, S3
SPI
MC68HC11
SPI
MC68HC05
SPI
RCA
CDP68HC05
SPI
Hitachi
HD6305
HD6301
HD63701
HD6303
HD64180
SCI Synchronous
SCI Synchronous
SCI Synchronous
SCI Synchronous
SCI Synchronous
National Semiconductor
COP400 Family
COP800 Family
NS8050U
HPC16000 Family
MICROWIRE^TM
MICROWIRE/PLUS^TM
MICROWIRE/PLUS
MICROWIRE/PLUS
Texas Instruments
TMS7002
TMS7042
TMS70C02
TMS70C42
TMS32011*
TMS32020
TMS370C050
Serial Port
Serial Port
Serial Port
Serial Port
Serial Port
Serial Port
SPI
*Requires external hardware
** Contact factory for interface information for processors not on this list
Hardware and Software Interface to COP402 Processor
LTC1290
COP402
CS
GO
SCLK
SK
ANALOG
•
INPUTS
•
•
DIN
SO
•
DOUT
SI
LTC1290 • AI08
D_OUT from LTC1290 Stored in COP402 RAM
MSB^†
LOCATION $13 B11 B10 B9 B8 FIRST 4 BITS
16
LOCATION $14 B7 B6 B5 B4 SECOND 4 BITS
LSB
LOCATION $15 B3 B2 B1 B0 THIRD 4 BITS
†_{B11 IS MSB IN UNIPOLAR OR SIGN BIT IN BIPOLAR}
National MICROWIRE (COP402)
The COP402 transfers data MSB first and in 4-bit incre-
ments (nibbles). This is easily accommodated by setting
the LTC1290 to MSB-first format and 12-bit word length.
The data output word is then received by the COP402 in
three 4-bit blocks.
COP402 Code
MNEMONIC
LOOP
CLRA
LBI 1,0
STII 8
STII E
STII 0
LEI C
SC
LDD 1,0
OGI 0
XAS
LDD 1,1
NOP
XAS
XIS 0
LDD 1,2
XAS
XIS 0
RC
CLRA
XAS
OGI 1
XIS 0
LBI 1,3
COMMENTS
Must be First Instruction
BR = 1BD = 0 Initialize B Reg.
First D_IN Nibble in $10
Second D_IN Nibble in $11
Null Data in $12, B = $13
Set EN to (1100) BIN
Carry Set
Load First D_IN Nibble In ACC
Go (CS) Cleared
ACC to Shift Reg. Begin Shift
Load Next D_IN Nibble in ACC
Timing
Next Nibble, Shift Continues
First Nibble D_OUT to $13
Put Null Data in ACC
Shift Continues, D_OUT to ACC
Next Nibble D_OUT to $14
Clear Carry
Clear ACC
Third Nibble D_OUT to ACC
Go (CS) Set
Third Nibble D_OUT to $15
Set B Reg. For Next Loop
Motorola SPI (MC68HC05C4)
The MC68HC05C4 transfers data MSB first and in 8-bit
increments. Programming the LTC1290 for MSB-first
format and 16-bit word length allows the 12-bit data
output to be received by the MPU as two 8-bit bytes with
the final four unused bits filled with zeros by the LTC1290.
MICROWIRE and MICROWIRE PLUS are trademarks of National Semiconductor Corp
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