WARNING! I'm still experimenting...Don't get used to the flavour just yet.
;; serial port to write to (setq *sout* (make-serial "pseudo0")) ;; the other end (setq *sin* (make-serial "pseudo1")) ;; write some (write-byte-seq *sout* (flexi-streams:string-to-octets "Hello World!")) ;; read some (flexi-streams:octets-to-string (cerial:read-byte-seq *sin* 12)) "Hello World!"
Or more 'idiomatically':
(with-serial (sout "pseudo1" :baudrate 115200 :parity :PARITY-ODD) (write-serial-byte sout 42))
For a full description of the API see the wiki pages of the future!