Atari 400 Technical Reference Manual page 308

ERR LINE ADDR B1 B2 B3 B4 SIO ( SERIAL BUS INPUT/OUTPUT CONTROLLER ) PAGE 47
2005 EABD 40 RTI
2006
2007
2008 EABE AO 00 NOTEND: LDY #0
2009 EACO B1 32 LDA (BUFRLO),Y iPUT NEXT BYTE FROM BUFFER
2010 EAC2 8D OD D2 STA SEROUT
i
INTO THE SERIAL OUTPUT REGISTER
2011
2012 EAC5
18 CLC iADD IT TO CHECKSUM
2013 EAC6 65 31
ADC
CHKSUM
2014 EAC8 69 00 ADC #0
2015 EACA 85 31 STA CHKSUM
2016
2017 EACC 4C BA EA wiMP CHKDON
i
GO RETURN
2018
2019
2020
2021
2022
2023
2024
i
TRANSMIT DONE INTERRUPT SERVICE ROUTINE
2025
2026 EACF A5 3B ISRTD: LDA CHKSNT
2027 EADl FO OB BEG FOOEY iBRANCH IF CHECKSUM NOT YET SENT
2028
i ,
2029 EAD3 85 3A STA XMTDON iOTHERWISE SET TRANSMISSION DONE FLAG
2030
2031 EAD5 A5 10 LDA POKMSK iDISABLE TRANSMIT DONE INTERRUPT
2032 EAD7 29 F7 AND #$F7
2033 EAD9 85 10 STA POKMSK
2034 EADB 80 OE D2 STA IRGEN
2035
2036 EADE
68 FOOEY: PLA
iRETURN FROM INTERRUPT
2037 EADF 40 RTI
2038
2039
2040
2041
2042
2043
2044
2045
2046
i
RECEIVE SUBROUTINE
2047
2048 EAEO A9 00 RECEIV: LOA #0
2049
2050 EAE2
AC OF 03 LOY CASFLG
2051 EAE5
DO 02 BNE NOCLR
iBRANCH IF CASSETTE
2052
2053 EAE7
85 31 STA CHKSUM
iCLEAR CHKSUM
2054 EAE9
85 38
NOCLR:
STA BUFRFL
iBUFFER FULL FLAG
2055 EAEB
85 39 STA RECVDN
iRECEIVE DONE FLAG
2056
2057
2058