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elyon
Joined: 21 Mar 2017
Posts: 9
Location: Italy
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| PIC18F2550 - HID Mouse Absolute Coordinates |
 Posted: Tue Mar 21, 2017 11:28 am |
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Hi all!! 
I'm a newbie in the world of CCS and PICs.
First of all, sorry for my bad english.
I'm here because I'm trying to use a PIC18F2550 as a mouse using the absolute coordinates to move the pointer to a specific position of the screen.
Elsewhere, I've read about the change of usb descriptor to do what I want, but in my ignorance I'm not sure about what I'm doing.
In my code, I connect my PIC to a device that, with SPI communication, send some words to it and, when it recognize them, it use two of this as the value of X and Y to move the pointer.
Searching, I've found a project here http://projectproto.blogspot.it/2009/11/pic18f2550-usb-hid-mouse.html
that use this function
| Code: | | usb_put_packet(1, out_data, 4, USB_DTS_TOGGLE); |
to move the pointer.
You can find the function in "usb_hw_layer.h"
These are my includes
| Code: | #include <pic18_usb.h>
#include <usb_desc_mouse.h>
#include <usb.c> |
And this is how I changed "usb_desc_mouse.h" like suggested where I read how to change it (I have change only USB_CLASS_SPECIFIC_DESC[]):
| Code: | const char USB_CLASS_SPECIFIC_DESC[] =
{
0x05, 0x01, // usage page (generic desktop Choose the usage page "mouse" is on
0x09, 0x02, // usage (mouse) Device is a mouse
0xA1, 0x01, // collection (application) This collection encompasses the report format
0x09, 0x01, // usage (pointer) Choose the key code usage page
0xA1, 0x00, // collection (physical) Physical collection
0x05, 0x09, // usage page (buttons) Choose the “button” usage page
0x19, 0x01, // usage minimum (1) There are three buttons
0x29, 0x03, // usage maximum (3)
0x15, 0x00, // logical minimum (0) Each button is represented by one bit
0x25, 0x01, // logical maximum (1)
0x95, 0x03, // report count (3) Three reports, one bit each
0x75, 0x01, // report size (1)
0x81, 0x02, // input (data, variable, absolute) Defined bits above are data bits
0x95, 0x01, // report count (1) One report, five bits in length
0x75, 0x05, // report size (5)
0x81, 0x01, // input (constant) Bit stuff to fill byte
0x05, 0x01, // usage page (generic desktop) Choose the usage pare “X” and “Y” are on
0x09, 0x30, // usage (X) X direction of pointer
0x09, 0x31, // usage (Y) Y direction of pointer
0x35, 0x00, // Physical minimum = 0
0x46, 0xFF,0x03, // Physical maximum = 1023
0x15, 0x00, // Logical Minimum = 0
0x26, 0xFF,0x03, // Logical Maximum = 1023
0x75, 0x08, // report size (8) Two reports, eight bits each
0x95, 0x02, // report count (3) 0x03
0x81, 0x02, // input (data, variable, relative) 0x06 Defined bits above are data bits
0xC0, // end collection End physical collection
0xC0 // end collection End application collection
}; |
In particular, I added
| Code: | 0x35, 0x00, // Physical minimum = 0
0x46, 0xFF,0x03, // Physical maximum = 1023 |
to define the physical resolution of my screen, and changed
| Code: | 0x15, 0x00, // Logical Minimum = 0
0x26, 0xFF,0x03, // Logical Maximum = 1023 |
Following also the HID Usage Table found here http://www.usb.org/developers/hidpage/Hut1_12v2.pdf
Now, I did things of which I know nothing, but could you tell me if I'm doing the right things and if the function | Code: | | usb_put_packet(1, out_data, 4, USB_DTS_TOGGLE); |
is the right choice to realize my project?
Thank you very much for every help that you can give me  |
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elyon
Joined: 21 Mar 2017
Posts: 9
Location: Italy
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| Posted: Wed Mar 29, 2017 1:39 am |
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no one? 
_________________
Think. Believe. Dream. Dare
- W. E. Disney - |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19499
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| Posted: Wed Mar 29, 2017 5:50 am |
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You need to change quite a lot of other stuff.
You've made your message larger, so the packet also has to grow.
Historically the standard mouse packet, is 'buttons', X, Y, wheel., with just one byte for each. You are sending 2 bytes for X and Y now...
Have a look at this MicroChip thread where another poster was doing the same thing:
<http://www.microchip.com/forums/m413261.aspx>
Also look for touchscreen examples online, which do exactly this. |
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elyon
Joined: 21 Mar 2017
Posts: 9
Location: Italy
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| Posted: Thu Mar 30, 2017 3:41 am |
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| Ttelmah wrote: | You need to change quite a lot of other stuff.
You've made your message larger, so the packet also has to grow.
Historically the standard mouse packet, is 'buttons', X, Y, wheel., with just one byte for each. You are sending 2 bytes for X and Y now...
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Hi Ttelmah! Thanks for the reply.
Yes, historically mouse has 3 "buttons" but in my case I don't need the wheel, so I haven't use it in my descriptor or in report size (report count is for only for 2 fields and report size is of 8 bit).
I'm not sure about this second configuration (8 bit) because, from the SPI, my PIC receive 16 bit for X and Y, so I have to change it from 8 bit (0x08) to 16 (0x10), I think.....
Anyway, I have already read the post you have linked, but there are many things that I don't find in my code, maybe because they use MPLAB compiler?
_________________
Think. Believe. Dream. Dare
- W. E. Disney - |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19499
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| Posted: Thu Mar 30, 2017 3:53 am |
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As I said, go and look at the thread I pointed you to, and search on touchscreen descriptors.
Your descriptor has a report size of 8 bits, for values that you are allowing to go to 1023..... |
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elyon
Joined: 21 Mar 2017
Posts: 9
Location: Italy
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| Posted: Fri Mar 31, 2017 4:37 am |
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oook. Thank you very much 
_________________
Think. Believe. Dream. Dare
- W. E. Disney - |
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