// ASI - Serial functions, these are here for the ASI type devices
// that are addressable and attache to the serial bus.
//
// UART 1 is used for communication and no handshaking is used. AS
// this is a UART then the devices will need the invert command
// in order for them to be read correctly

// *******************************************************************
// gets keys in buffer, normally inp would be used but when
// multiple devices are connected there is no unique terminating
// character
// *******************************************************************
function asi_in$
dim a$=""
    while key?(1) <> 0
        a$=a$+chr$(key(1))
    wend    
endf
// *******************************************************************
// returns a string containing the addresses of all of the devices
// separated by '>'. If 3 devices are connected say j,p and b then
// the string returned will be a>j>p>. There is no CR on the end
// of the string -- use split to get the individual addresses
// *******************************************************************              
function asi_find$(baud)
dim a$
    opencom 1 baud 0        // open com port
    out 1 13:wait 100       // delay needed to establish baud rate
    out 1 13:wait 100       // send initialisation
    out 1 4                 // invert
    out 1 13:wait 50
    out 1 1                 // devices id
    out 1 13:wait 50
    // device 'z' will take up to 780ms to respond
    wait 800
    result asi_in$
endf

// *******************************************************************
// writing to a device. Address must be embedded in the s$ string
// this will wait for the '>' before returning. A sucessful
// write returns a sting    
// *******************************************************************
function asi_write$(s$)
dim rv, a$[:4]
    out$ 1 s$+*13       // write followed by CR
    rv=inp(1,a$,50,'>')
    result a$
endf              

// *******************************************************************
// Reading a value n...> Values are sent as tect so this will translate
// and return the value in binary, example:
// print asi_send("av")  // returns BV4113 analogue input value
// *******************************************************************              
function asi_read(s$)
dim in$[:5], rv=0, length, digit=1, v
    out$ 1 s$+*13       // send commad
    length = inp(1,in$,10,'>') 
    if length > 0 then  // something recieved
        while length > 1    // dont want terminating '>'
             length=length-1     
             v=asc(in$,digit)-48  // convert ascii to number
             rv=(rv*10)+v
             digit=digit+1
        wend
    endif
    result rv         
endf

function xx
//    print asi_find$(9600)
    asi_change_address
    print "inpbuf$=";inpbuf$(1)
endf