18
LTC1599
sn1599 1599fs
APPLICATIONS INFORMATION
WU
U
GETDATA PSHX
PSHY
PSHA
LDY
#$1000
Setup index
*
*****************************************
* Retrieve DAC data from memory and
*
* send it to the LTC1599
*
*****************************************
*
LDAA
LBYTE
Retrieve the least significant byte from memory
BCLR
PORTA,Y %00010000
This sets PORTA, Bit4 output to a logic
*
low, forcing MLBYTE input to a logic low
BCLR
PORTA,Y %00001000
This forces a low on the LTC1599’s WR pin
STAA
PORTB
Transfer the least significant byte to the DAC
BSET
PORTA,Y %00001000
This forces a high on the LTC1599’s WR pin
BSET
PORTA,Y %00010000
This sets PORTA, Bit4 output to a logic
*
high, forcing MLBYTE to a logic high
LDAA
MBYTE
Retrieve the most significant byte from memory
BCLR
PORTA,Y %00001000
This forces a low on the LTC1599’s WR pin
STAA
PORTB
Transfer the most significant byte to the DAC
BSET
PORTA,Y %00001000
This forces a high on the LTC1599’s WR pin
*
*******************************************
* The next two instructions exercise
*
* the LD input, latching the data
*
* that was just loaded
*
*******************************************
*
BCLR
PORTD,Y %00100000
LD goes low
BSET
PORTD,Y %00100000
and returns high
*
*******************************************
* Data transfer routine completed
*
*******************************************
*
PULA
Restore the A register
PULY
Restore the Y register
PULX
Restore the X register
RTS