bits ~-2 bit 3 interrupting modern channel number modem interrupt bits 4-6 bit 7 interrupting receiver channel number receive interrupt bits 8-l~ bit 11 interrupting transmitter channel number transmit interrupt New Command Register The new command register is an eight bit register used to indi- cate the existence of a new command. This register should be incremented any time a command is written into the system command register, or any of the five channel command registers. Communication Channel Registers Channel Parameter Register The channel parameter register is a 16-bit register containing the following information:
Async mode bit ~ bit 1 bits 2-3 parity enable parity even =~ =1 1 stop bit =2 1.5 stop bits =3 2 stop bits bits 4-5 =~ 5 bits per character =1 7 bits per character =2 6 bits per character =3 8 bits per character unused bit 6 bit 7 ring buffer receiver enable/-TTY bits 8-11 =~ selectable rate =1 75 bps =2 ll~ bps =3 134.5 bps =4 150 bps =5 3~0 bps =6 600 bps =7 l20~ bps =8 1800 bps =9 2~00 bps =l~ 240~ bps =11 360~ bps 5-32