MC33298 Motorola, MC33298 Datasheet - Page 21

• Manufacturer Part Number: MC33298
• Description: OCTAL SERIAL SWITCH (SPI Input/Output)
• Manufacturer: Motorola

SPI TRANSFER LOOP
ESTABLISH A BRIEF DELAY
SUBROUTINE TO CHECK FOR FAULTS
MOTOROLA ANALOG IC DEVICE DATA
LOOP
DOONE
GOON
WZZER0
PAUSE
FLTCHK
NOFLT
BRCLR
DECX
DECA
BCLR
BSET
BSET
BSET
BCLR
BSET
BCLR
BSET
BCLR
BSET
CMP
BCS
BNE
BRA
BEQ
LDX
JMP
LDA
JSR
JSR
LDA
RTS
ASL
ASL
BPL
0,PORTA,
0,DATAIN
7,PORTA
7,PORTA
6,PORTA
WZZER0
6,PORTA
5,PORTA
5,PORTA
5,PORTA
1,PORTA
1,PORTA
FLTCHK
DOONE
DATAIN
DTOUT
DATAIN
PAUSE
VALUE
NOFLT
GOON
LOOP
#$07
TOP
DLY
#16
;Set the number of Read/Shift cycles.
;Shift a Zero into LSB of DATAIN and ASL other bits.
;Test value currently in MSB of DTOUT.
;
;MSB was Zero, so clear DATA OUT bit.
;MSB was One, so set the DATA OUT bit.
;Set the SCLK. Serial Output pin of the MC33298 changes state on the rising edge of the SCLK.
Read the next bit coming from the MC33298.
;Read the bit and branch if Zero. LSB of DATAIN is already cleared due to the ASL above.
;Bit was One. Set the next bit in DATAIN.
;Clear SCLK. Falling edge causes the MC33298 to read the next bit from the MCU.
;Continue to loop eight times until the SPI transfer is complete.
;Transfer control signal to output transistors.
;3 Clock cycles
;3 Clock cycles
;Transfer output status to Serial Register.
;Jump to Fault Check subroutine.
;Delay 1/T msec
;Deselect the MC33298.
;Return to top of loop.
;CLR the Fault pin.
;Check for Faults.
;If there is no Fault, continue.
;Activate Fault LED.
MC33298
21