LTC1283 View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
'LTC1283' PDF : 24 Pages View PDF
LTC1283
TYPICAL APPLICATI S
Sneak-A-Bit Code for the LTC1283 Using the MC68HC05C4
MNEMONIC
DESCRIPTION
LDA #$50
CONFIGURATION DATA FOR SPCR
STA $0A
LOAD CONFIGURATION DATA INTO $0A
LDA #$FF
CONFIGURATION DATA FOR PORT C DDR
STA $06
LOAD CONFIGURATION DATA INTO PORT
C DDR
BSET 0, $02 MAKE SURE CS IS HIGH
JSR READ –/+ DUMMY READ CONFIGURES LTC1283 FOR
NEXT READ
JSR READ +/– READ CH6 WITH RESPECT TO CH7
JSR READ –/+ READ CH7 WITH RESPECT TO CH6
JSR CHK SIGN DETERMINES WHICH READING HAS VALID
DATA, CONVERTS TO 2’s COMPLEMENT
AND STORES IN RAM
READ – / +: LDA #$3F
LOAD DIN WORD FOR LTC1283 INTO ACC
JSR TRANSFER READ LTC1283 ROUTINE
LDA $60
LOAD MSBs FROM LTC1283 INTO ACC
STA $71
STORE MSBs IN $71
LDA $61
LOAD LSBs FROM LTC1283 INTO ACC
STA $72
STORE LSBs IN $72
RTS
RETURN
Read + / –: LDA #$7F
LOAD DIN WORD FOR LTC1283 INTO ACC
JSR TRANSFER READ LTC1283 ROUTINE
LDA $60
LOAD MSBs FROM LTC1283 INTO ACC
STA $73
STORE MSBs IN $73
LDA $61
LOAD LSBs FROM LTC1283 INTO ACC
STA $74
STORE LSBs IN $74
RTS
RETURN
TRANSFER: BCLR 0, $02
CS GOES LOW
STA $0C
LOOP 1: TST $0B
LOAD DIN INTO SPI. START TRANSFER
TEST STATUS OF SPIF
BPL LOOP 1 LOOP TO PREVIOUS INSTRUCTION IF NOT
DONE
LDA $0C
LOAD CONTENTS OF SPI DATA REG. INTO
ACC
STA $0C
START NEXT CYCLE
STA $60
STORE MSBs IN $60
MNEMONIC
LOOP 2: TST $0B
BPL LOOP 2
BSET 0, $02
LDA $0C
STA $61
RTS
CHK SIGN: LDA $73
ORA $74
BEQ MINUS
CLC
ROR $73
ROR $74
LDA $73
STA $77
LDA $74
STA $87
BRA END
MINUS: CLC
ROR $71
ROR $72
COM $71
COM $72
LDA $72
ADD #$01
STA $72
CLRA
ADC $71
STA $71
STA $77
LDA $72
STA $87
END:
RTS
DESCRIPTION
TEST STATUS OF SPIF
LOOP TO PREVIOUS INSTRUCTION IF NOT
DONE
CS GOES HIGH
LOAD CONTENTS OF SPI DATA REG. INTO
ACC
STORE LSBs IN $61
RETURN
LOAD MSBs OF +/– READ INTO ACC
OR ACC (MSBs) WITH LSBs OF +/– read
IF RESULT IS 0 GOTO MINUS
CLEAR CARRY
ROTATE RIGHT $73 THROUGH CARRY
ROTATE RIGHT $74 THROUGH CARRY
LOAD MSBs OF +/– READ INTO ACC
STORE MSBs IN RAM LOCATION $77
LOAD LSBs OF +/– READ INTO ACC
STORE LSBs IN RAM LOCATION $87
GOTO END OF ROUTINE
CLEAR CARRY
SHIFT MSBs OF –/+ READ RIGHT
SHIFT LSBs –/+ READ RIGHT
1’s COMPLEMENT OF MSBs
1’s COMPLEMENT OF LSBs
LOAD LSBs INTO ACC
ADD 1 TO LSBs
STORE ACC IN $72
CLEAR ACC
ADD WITH CARRY TO MSBs. RESULT IN
ACC
STORE ACC IN $71
STORE MSBs IN RAM LOCATION $77
LOAD LSBs IN ACC
STORE LSBs IN RAM LOCATION $87
RETURN
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of circuits as described herein will not infringe on existing patent rights.
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