USBDemo, something to learn USB a little bit

[Darrel Taylor]

Enable bits (IE), Interrupt Flags (IF) or Priority bits (IP).
Don't "mess" with them. That includes GIE and PEIE or GIEL.

Many interrupt sources have registers that affect the specific peripheral.
For instance ...

• If you don't set TXSTA and RCSTA then you will never get proper interrupts from the USART.
  
• If you don't set T1CON, you will never get interrupts from TMR1_INT.
  
• And ...
  If you don't set the INTEDG bits, you may never get the correct interrupt from INT2_INT.
  

You have to tell the hardware how to handle the signals.
DT_INTS will handle the interrupts.
<br>

[Mark J]

Hi Guys,

Ive got a bit of a problem with the USB thats got me stumped and hope you can help.

Im using DT's interupts and have setup INT_INT to read a DS18S20+ temp sensor which works fine and I can display it on the LCD lovely.

My problem is that trying to use the USB it works with the interupt for the temp probe ok, but as SOON as I use LCDOUT I get the USB device not recognised

Even splattering USBSERVICE after all the lines in the main loop it still wont recognise it.

I have tried both ON INTERUPT and DT's TMR0_INT for the USBSERVICE but nothing I do will get it working unless the LCDOUT is removed.

I can post the code if required but thought I would just write the problem first in case its something obvious im missing.

Many thanks,

Mark

[Mark J]

Doh, I suppose I should have looked a bit more deeply on the forum! lol.
I did see this ages ago and it slipped my memory, but found DT's USB_ASM_Service file and tried that and BINGO! sorted it PHEW!

Must say thanks to DT as it seems that whenever I see someone (even myself!) get stuck with something, a quick delve into the forums usually finds a post by Darrel that sorts it!

Mark

[sjm2000]

Hi,
I am new and this is my first posting, please don't shoot me in case of mistakes.

Today I started to use PicPasic Pro 2.6 with MPLAB IDE 8.60 and tried out the usb_demo.bas sample immediately.

MPLAB file list:
CDC_DEMO.BAS
CDC_DESC.BAS
USB_CDC.ASM
USB_CDC.INC
USB_MEM.ASM
USB_DEV.ASM
USB_DEV.INC


CDC_DEMO.BAS Code:

' USB sample program for PIC18F4550 CDC serial port emulation
'  Requires PBP 2.60 or later

'  Compilation of this program requires that specific support files be
'  available in the source directory.  For detailed information, see
'  the file PBP\USB18\USB.TXT.

	Include	"cdc_desc.bas"	' Include the HID descriptors

Define  OSC     48

buffer	Var	Byte[16]
cnt	Var	Byte


	OSCTUNE.6 = 1		' Enable PLL for 18F87J50 family
	Pause 10

	USBInit			' Get USB going

' Wait for USB input
idleloop:
	USBService		' Must service USB regularly
	cnt = 16		' Specify input buffer size
	USBIn 3, buffer, cnt, idleloop

' Message received
	buffer[0] = "H"
	buffer[1] = "e"
	buffer[2] = "l"
	buffer[3] = "l"
	buffer[4] = "o"
	buffer[5] = " "
	buffer[6] = "W"
	buffer[7] = "o"
	buffer[8] = "r"
	buffer[9] = "l"
	buffer[10] = "d"
	buffer[11] = 13
	buffer[12] = 10
	buffer[13] = 0

outloop:
	USBService		' Must service USB regularly
	USBOut 3, buffer, 14, outloop

	Goto idleloop		' Wait for next buffer

The test program in the PC is a simple VB6 routine:

;---------------- Write to PIC --------------------------
Private Sub Out3Byte(bus As Byte, adr As Byte, data As Byte)
Dim Com(2) As Byte
Com(0) = bus: Com(1) = adr: Com(2) = data
    '3 byte send
    MSComm1.Output = Com
End Sub
;----------------- Receive from PIC ----------------------
Private Sub MSComm1_OnComm()
Dim data As String, ende As Boolean
ende = False: Text1.Text = ""
    Static IsActive As Boolean
    MSComm1.RThreshold = 0
    If IsActive Then
        Label4.Caption = "OnComm Ueberschneidung"
       Exit Sub
    End If
        Do Until ende
            If MSComm1.InBufferCount > 1 Then     'min 1byte recvd
            data = MSComm1.Input
            Text1.Text = Text1.Text + Hex$(AscB(data)) + " "
            Else
            ende = True
            End If
        DoEvents
        Loop
IsActive = False
MSComm1.RThreshold = 1
End Sub

In general it works fine but, for one little but crucial problem I cant find the reason, so I suspect the problem to be with the PBP compilation.

The 3 bytes from the PC are always received properly, but the "Hello World" message arrives in the PC correctly only the first time immediately after Com Port Open statement. When continuously sending and receiving, at the beginning of the messages there is always one garbage byte ahead of "Hello World". The value is always the same, but depends one actual memory location in PIC RAM of "buffer Var Byte[16]"

Can anyone help?

CDC_DEMO_transmission_log:

35	VB6.EXE	IOCTL_SERIAL_SET_BAUD_RATE	USBSER000	SUCCESS	Rate: 115200	
36	VB6.EXE	IOCTL_SERIAL_CLR_RTS	USBSER000	SUCCESS		
37	VB6.EXE	IOCTL_SERIAL_SET_DTR	USBSER000	SUCCESS		
38	VB6.EXE	IOCTL_SERIAL_SET_LINE_CONTROL	USBSER000	SUCCESS	StopBits: 1 Parity: NONE WordLength: 8	
39	VB6.EXE	IOCTL_SERIAL_SET_CHAR	USBSER000	SUCCESS	EOF:1a ERR:0 BRK:0 EVT:0 XON:11 XOFF:13	
40	VB6.EXE	IOCTL_SERIAL_SET_HANDFLOW	USBSER000	SUCCESS	Shake:1 Replace:0 XonLimit:8000 XoffLimit:8000	
41	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
42	VB6.EXE	IRP_MJ_WRITE	USBSER000	SUCCESS	Length 3: A1 A9 AF	<3 bytes send 	
43	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
44	VB6.EXE	IOCTL_SERIAL_SET_WAIT_MASK	USBSER000	SUCCESS	Mask: RXCHAR TXEMPTY CTS DSR RLSD BRK ERR RING 	
45	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
46	VB6.EXE	IOCTL_SERIAL_WAIT_ON_MASK	USBSER000	SUCCESS		
47	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
48	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 48 	   <----- Starts with "H"
49	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
50	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
51	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 65 	
52	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
53	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
54	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 6C 	
55	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
56	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
57	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 6C 	
58	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
59	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
60	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 6F 	
61	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
62	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
63	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 20 	
64	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
65	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
66	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 57 	
67	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
68	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
69	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 6F 	
70	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
71	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
72	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 72 	
73	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
74	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
75	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 6C 	
76	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
77	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
78	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 64 	
79	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
80	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
81	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 0D 	
82	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
83	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
84	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 0A 	
85	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
86	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
87	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
88	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
89	VB6.EXE	IOCTL_SERIAL_GET_PROPERTIES	USBSER000	SUCCESS		
90	VB6.EXE	IRP_MJ_WRITE	USBSER000	SUCCESS	Length 3: A1 A9 AF	<3bytes send 	
91	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
92	VB6.EXE	IOCTL_SERIAL_SET_WAIT_MASK	USBSER000	SUCCESS	Mask: RXCHAR TXEMPTY CTS DSR RLSD BRK ERR RING 	
93	B6.EXE	IOCTL_SERIAL_WAIT_ON_MASK	USBSER000	SUCCESS		
94	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
95	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
96	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 00		<----- starts with "0x00"
97	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
98	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
99	B6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 48 		<----- "H" is 2nd byte
100	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
101	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
102	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 65 	
103	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
104	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
105	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 6C 	
106	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
107	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
108	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 6C 	
109	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
110	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
111	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 6F 	
112	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
113	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
114	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 20 	
115	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
116	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
117	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 57 	
118	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
119	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
120	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 6F 	
121	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
122	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
123	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 72 	
124	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
125	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
126	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 6C 	
127	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
128	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
129	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 64 	
130	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
131	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
132	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 0D 	
133	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
134	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
135	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 0A 	
136	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
137	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
138	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
139	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
140	VB6.EXE	IOCTL_SERIAL_GET_PROPERTIES	USBSER000	SUCCESS		
141	VB6.EXE	IRP_MJ_WRITE	USBSER000	SUCCESS	Length 3: A1 A9 AF	<3 bytes send	
142	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
143	VB6.EXE	IOCTL_SERIAL_SET_WAIT_MASK	USBSER000	SUCCESS	Mask: RXCHAR TXEMPTY CTS DSR RLSD BRK ERR RING 	
144	VB6.EXE	IOCTL_SERIAL_WAIT_ON_MASK	USBSER000	SUCCESS		
145	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
146	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
147	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 00 <garbage again
148	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
149	VB6.EXE	IOCTL_SERIAL_GET_COMMSTATUS	USBSER000	SUCCESS		
150	VB6.EXE	IRP_MJ_READ	USBSER000	SUCCESS	Length 1: 48 

[sjm2000]

Hi,

I am still stuck with my proplem, therefore, I modified the cdc_demo.bas to be able to change the outbuffer contents:

' USB sample program for PIC18F4550 CDC serial port emulation
'  Requires PBP 2.60 or later

'  Compilation of this program requires that specific support files be
'  available in the source directory.  For detailed information, see
'  the file PBP\USB18\USB.TXT.

	Include	"cdc_desc.bas"	' Include the HID descriptors

Define  OSC     48

inbuffer	Var	Byte[15]
outbuffer	Var	Byte[15]
icnt	Var	Byte
ocnt	Var	Byte

	OSCTUNE.6 = 1		' Enable PLL for 18F87J50 family
	Pause 10

	USBInit			' Get USB going

' Wait for USB input
idleloop:

	icnt = 6		' Specify input buffer size
	USBService		' Must service USB regularly
	USBIn 3, inbuffer, icnt, idleloop

' Message received
	outbuffer[0] = inbuffer[0]
	outbuffer[1] = inbuffer[1]
	outbuffer[2] = inbuffer[2]
	outbuffer[3] = inbuffer[3] 
	outbuffer[4] = 0
	outbuffer[5] = icnt
	outbuffer[6] = 0
	outbuffer[7] = $AA
	outbuffer[8] = $BB
	outbuffer[9] = $CC
	outbuffer[10] = $DD
	outbuffer[11] = 0
	outbuffer[12] = inbuffer[0]
	outbuffer[13] = inbuffer[1]
	outbuffer[14] = inbuffer[2]

outloop:
	USBService		' Must service USB regularly
	ocnt = 14
	USBOut 3, outbuffer, ocnt, outloop

	Goto idleloop		' Wait for next buffer

I continued testing and found out:

With ocnt = 14

The first USBOut after com port open in PC test program is actually

outbuffer[0]....outbuffer[12] -> in total 13 bytes

from the second output it is always the same

outbuffer[13], outbuffer[0], outbuffer[1]...., outbuffer[12] ->in total 14 bytes


I suspect in the appended .inc and .asm files might be a definition mistake, but since I do not understand the code written there, I really need the help of an USB specialist in this Forum to overcome this problem.

To all the USB experts in this Forum, please Help.