; TITLE ZMH8-1.Z80 - 01/01/88 - ZMD I/O Overlay for HEATH/ZENITH 89 ; Copyrighted (c) 1987, 1988 ; Robert W. Kramer III PAGE ;- -; ; Update History ; ; ; ; Date Release Comments ; ; -------- ------- ---------------------------------------------- ; ; ; ; 01/01/88 v1.00 - Initial version ; ;- -; ; MODDATP EQU 0D8H ; Data in port MODDATO EQU MODDATP ; Data out port MODCTLP EQU MODDATP+5 ; Line status register MODCTL2 EQU MODDATP+6 ; Modem status register MODSNDB EQU 20H ; Bit to test for send MODSNDR EQU 20H ; Value when ready MODRCVB EQU 1 ; Bit to test for receive MODRCVR EQU 1 ; Value when ready MODDCDA EQU 10H ; Value when active MODDCDB EQU 10H ; Carrier detect bit MODPARE EQU 4 ; Value for parity error MODOVRE EQU 2 ; Value for overrun error MODFRME EQU 8 ; Value for framing error ; ;-------------------------------------------------------------------------; ; Input/Output Jump Table | ;-------------------------------------------------------------------------; ; ORG 0580H ; Start after configuration table JP 0000H ; See CONOUT.INF JP INIT ; Initialization routine JP UNINIT ; Unititialize routine JP SNDCHR ; Send character JP CARCHK ; Test for carrier JP GETCHR ; Get character from modem JP RCVRDY ; Check receive ready JP SNDRDY ; Check send ready ; ;-------------------------------------------------------------------------; ; System startup inititialization routine | ;-------------------------------------------------------------------------; INIT: RET ; ;-------------------------------------------------------------------------; ; System exit unititialization routine | ;-------------------------------------------------------------------------; UNINIT: RET ; ;-------------------------------------------------------------------------; ; Send character out modem | ;-------------------------------------------------------------------------; SNDCHR: POP AF ; Get the character back OUT (MODDATO),A ; Send it to the modem output RET ; ;-------------------------------------------------------------------------; ; Check for carrier | ;-------------------------------------------------------------------------; CARCHK: IN A,(MODCTL2) ; Read modem status AND MODDCDB ; Get carrier detect bit CP MODDCDA ; Test bit RET ; ;-------------------------------------------------------------------------; ; Get character from modem | ;-------------------------------------------------------------------------; GETCHR: IN A,(MODDATP) ; Get character from data in port RET ; ;-------------------------------------------------------------------------; ; Check modem receive ready | ;-------------------------------------------------------------------------; RCVRDY: IN A,(MODCTLP) ; Get modem status PUSH BC ; Save scratch register PUSH AF ; Check error status AND MODFRME+MODOVRE+MODPARE LD B,A ; Save it for a moment POP AF AND MODRCVB ; Isolate ready bit CP MODRCVR ; Test it LD A,B ; Get the error code char. back POP BC RET ; ;-------------------------------------------------------------------------; ; Check modem send ready | ;-------------------------------------------------------------------------; SNDRDY: IN A,(MODCTLP) ; Get status byte AND MODSNDB ; Isolate ready bit CP MODSNDR ; Ready to send? RET END