Receiving a control string from an FTDI serial interface

[Terry Platt]

Hi All,
This is probably a simple question to answer, but some advice would be appreciated. I have a small board with an FTDI input chip and a 16F687 processor. This is intended for controlling some small servos in an optical device and expects to receive blocks of 7 characters at intervals from the PC. These character strings are typically something like 'MN00010' and are decoded to provide direction and speed information. The problem is that I have used some of the GC demo examples, but they all seem to receive single characters, rather than strings. Can I easily receive a 7 character string at each download?
Thanks for any solutions!

[mkstevo]

For receiving the track count from a DfPlayer MP3 module, I use this:

#Chip 16F1829, 32
#Define Ser_In        PortA.3
#Define SerDF         PortA.5
#Define SendAHigh Set SerDF On        'Serial Out                      (-)      Pin2 Pin2 DFPlayer
#Define SendALow  Set SerDF Off       'Serial Out                      (-)      Pin2 Pin2 DFPlayer

#Define RecAHigh  Ser_In On           'Serial In                       (-)      Pin4 Pin3 DFPlayer
#Define RecALow   Ser_In Off          'Serial In                       (-)      Pin4 Pin3 DFPlayer

InitSer 1, r9600, 1 + WaitForStart, 8, 1, none, normal
SendAHigh                              'Idle High
Dim     SerData(10)  'As Array
Dim     ReturnTracks  As Word

Sub Serial_Fetch

    Let ReturnTracks = 0

    SerReceive 1, SerData(1) '0x7e
    SerReceive 1, SerData(2) '0xff
    SerReceive 1, SerData(3) '0x06
    SerReceive 1, SerData(4)
    SerReceive 1, SerData(5)
    SerReceive 1, SerData(6) 'High Byte of track count
    SerReceive 1, SerData(7) 'Low  Byte of track count
    SerReceive 1, SerData(8) '0xef

    If SerData(6) > 0 Then
          Let ReturnTracks = SerData(6)
          Let ReturnTracks = ReturnTracks * 256 'High Byte
    End If

    If SerData(7) > 0 Then
          Let ReturnTracks = ReturnTracks + SerData(7) 'Low Byte
    End If

End Sub

As you can see, this returns 8 bytes of data which are placed in the array SerData(), so maybe you could use something similar for your 7 bytes? It has worked reliably for me. The entire code for the program is posted in the finished projects area, as my MP3 mini jukebox project if this doesn't make a deal of sense by itself.

[William Roth]

@Terry Platt

Since your device has a USART, you can use HSerGetString to receive strings. Usage is described in the Help File under: Command Reference >> Serial Communication >> RS232 ( hardware) >> HserGetString. The string being sent must be terminated with a Carriage Return.

There is an example provided in the Help File.

William

[Terry Platt]

Hi William (and mkstevo),
Thanks for the ideas - it looks like the HSerGetString command will do the trick. I'm now seeing the correct responses from the board.
Many thanks!
Terry