SP2-433-160 Datasheet, PDF (24/27 Pages) Radiometrix Ltd – UHF SpacePort Transceiver

**********************************************************************
* RANDOM ACCESS MEMORY
*
*********************************************************************
ORG RAM
;RAM AREA DEFINITION
SAVE_1
SAVE_X
RMB 1
RMB 2
;TEMPORARILY SAVE LOCATION 1
;HOLDS FILES POINTER FOR IN_BYTE
**********************************************************************
* SUBROUTINE: IN_BYTE
*
*********************************************************************
*This subroutine is designed to be called by an interrupt handler to
*read a byte from the SP2 into a file pointed at by X
*
*Note: The interrupt handler should load the X register with the file address
before calling this subroutine.
IN_BYTE
WAIT_RQ
IN_LP
WAIT_RQ1
DAT_IN
WAIT_RQ2
IN_LP2
WAIT_RQ3
DAT_IN2
READ_END
CLR
LDAB
STAB
LDAB
BITB
BNE
LDAB
ANDB
STAB
LDAB
BITB
BEQ
LDAA
ANDA
LDAB
ORAB
STAB
STAA
LDAB
BITB
BNE
LDAB
ANDB
STAB
LDAB
BITB
BEQ
LDAA
ANDA
ASLA
ASLA
ASLA
ASLA
LDAB
ORAB
STAB
ORAA
STAA
STAA
SAVE_1
#%10010000
DDRC
PORTC
#%01000000
WAIT_RQ
PORTC
#%01111111
PORTC
PORTC
#%01000000
WAIT_RQ1
PORTC
#%00001111
PORTC
#%10000000
PORTC
SAVE_1
PORTC
#%01000000
WAIT_RQ2
PORTC
#%01111111
PORTC
PORTC
#%01000000
WAIT_RQ3
PORTC
#%00001111
PORTC
#%10000000
PORTC
SAVE_1
SAVE_1
0,X
;CLEAR TEMPORARILY MEMORY LOCATION
;SET CORRECT DATA DIRECTION i/p
;WAIT FOR RX-REQUEST TO GO LOW
;
;FORCE RX-ACCEPT TO GO LOW
;WAIT FOR RX-REQUEST TO GO HIGH
;READ IN DATA
;FORCE ACCEPT HIGH
;SAVE NIBBLE TO TEMP LOCATION
;WAIT FOR RX-REQUEST TO GO LOW
;FORCE RX-ACCEPT TO GO LOW
;WAIT FOR RX-REQUEST TO GO HIGH
;READ IN DATA
;FORCE ACCEPT HIGH
;PUT NIBBLES TOGETHER IN TEMP LOCATION
;SAVE DATA TO POINTER ADDRESS
Radiometrix Ltd, SP2 data sheet
page 24