Datasheet

16
LTC1290
1290fe
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MICROWIRE and MICROWIRE PLUS are trademarks of National Semiconductor Corp
LTC1290 • AI08
SCLK
D
OUT
LTC1290
CS
ANALOG
INPUTS
GO
SK
SI
COP402
D
IN
SO
B6 B5
B4
B7
FIRST 4 BITS
SECOND 4 BITS
B10 B9 B8B11
D
OUT
from LTC1290 Stored in COP402 RAM
MSB
†
LOCATION $13
LOCATION $14
B2 B1
B0
B3
THIRD 4 BITS
LSB
LOCATION $15
•
•
•
•
†
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 COMMENTS
CLRA Must be First Instruction
LBI 1,0 BR = 1BD = 0 Initialize B Reg.
STII 8 First D
IN
Nibble in $10
STII E Second D
IN
Nibble in $11
STII 0 Null Data in $12, B = $13
LEI C Set EN to (1100) BIN
LOOP SC Carry Set
LDD 1,0 Load First D
IN
Nibble In ACC
OGI 0 Go (CS) Cleared
XAS ACC to Shift Reg. Begin Shift
LDD 1,1 Load Next D
IN
Nibble in ACC
NOP Timing
XAS Next Nibble, Shift Continues
XIS 0 First Nibble D
OUT
to $13
LDD 1,2 Put Null Data in ACC
XAS Shift Continues, D
OUT
to ACC
XIS 0 Next Nibble D
OUT
to $14
RC Clear Carry
CLRA Clear ACC
XAS Third Nibble D
OUT
to ACC
OGI 1 Go (CS) Set
XIS 0 Third Nibble D
OUT
to $15
LBI 1,3 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.
Hardware and Software Interface to COP402 Processor
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 SCI Synchronous
HD6301 SCI Synchronous
HD63701 SCI Synchronous
HD6303 SCI Synchronous
HD64180 SCI Synchronous
National Semiconductor
COP400 Family MICROWIRE
TM
COP800 Family MICROWIRE/PLUS
TM
NS8050U MICROWIRE/PLUS
HPC16000 Family MICROWIRE/PLUS
Texas Instruments
TMS7002 Serial Port
TMS7042 Serial Port
TMS70C02 Serial Port
TMS70C42 Serial Port
TMS32011* Serial Port
TMS32020 Serial Port
TMS370C050 SPI
*Requires external hardware
** Contact factory for interface information for processors not on this list