' pinpi.bas performs digital I/O with MMB4L
'
dim integer i,j,k,p(4)=(0,12,16,20,21)
dim integer pState(16)
dim integer q(4)=(0,25,8,7,1), dout=1, din=0

for i=1 to 4
 setpin p(i),dout
 cmd$="echo '1' > /sys/class/gpio/gpio"+str$(p(i))+"/value"
 system(cmd$)
 pause 500
next
for i=1 to 4
 setpin q(i),din
 cmd$="echo '0' > /sys/class/gpio/gpio"+str$(p(i))+"/value"
 system(cmd$)
 pause 500
next

do
 for i=1 to 4
   open "/sys/class/gpio/gpio"+str$(q(i))+"/value" for input as #1
   a$=input$(1,#1): close #1 ' 0 or 1
   cmd$="echo '"+a$+"' > /sys/class/gpio/gpio"+str$(p(i))+"/value"
'    print cmd$
   system(cmd$)
 next i
 pause 2000
loop

sub setpin(pinno as integer, pinmode as integer)
 local string dirname$, cmd$
 dirname$="/sys/class/gpio/gpio"+str$(pinno)
 if not MM.INFO(EXISTS DIR dirname$) then
   cmd$="echo '"+str$(pinno)+"' > /sys/class/gpio/export 2>/dev/null"
'    print cmd$
   system(cmd$)
   pause 200
 endif
 dirname$=dirname$+"/direction"
 if pinmode then
   cmd$="echo 'out' > "+dirname$
 else
   cmd$="echo 'in' > "+dirname$
   system(cmd$)
   pause 200
   cmd$="gpio -g mode "+str$(pinno)+" up" ' set weak pullup
 endif
 ?pinno,cmd$
 system(cmd$)
 pause 200
end sub

Local i%
For i% = 1 To 600
 If Not Mm.Info(Exists path$) Pause 10
Next
If Not Mm.Info(Exists path$) Error "I hate the GPIO"

' linux serial test program
'  OPEN "/dev/ttyUSB0" FOR RANDOM AS #5 ' open the serial port
'  OPEN "/dev/serial1" FOR RANDOM AS #5 ' open the serial port
 OPEN "/dev/serial1" FOR output AS #5 ' open the serial port
 PRINT #5, "HELLO!!! Is anyone out there?"
 DO ' one way to receive serial data which might not be there!
   k$ = INPUT$(1,#5)
   IF k$="" THEN
     nodata=nodata+1
   ELSE
     result$=result$+k$
     PRINT result$
     nodata=0
   ENDIF
   PAUSE 20
 LOOP UNTIL k$=CHR$(10)OR nodata=50 ' 50*20ms = 1 second timeout
 CLOSE #5

sudo adduser thwill dialout

' I don't understand half this incantation, but whilst experimenting I
' discovered that 'screen /dev/ttyS0 115200' connected to the CMM2
' successfully and these correspond to the difference between the settings
' before and after 'screen' was run.
System "stty -F /dev/ttyS0 115200 min 100 time 2 cs8 -cstopb -parenb -hupcl brkint ignpar -icrnl -opost -onlcr -isig -icanon -echo"

Open "/dev/ttyS0" For Output As #1
Open "/dev/ttyS0" For Input As #2

Dim s$

Print #1, "Print " + Chr$(34) + "Hello MMB4L" + Chr$(34)
Line Input #2, s$
Print s$

Dim i
For i = 1 To 5
 Print #1, "Print " + Chr$(34) + Str$(i) + Chr$(34)
 Line Input #2, s$
 Print s$
 Line Input #2, s$
 Print s$
Next

Print "Hello MMB4L"
Hello MMB4L
> Print "1"
1
> Print "2"
2
> Print "3"
3
> Print "4"
4
> Print "5"