General • Re: Using Raspberry Pi Pico as HID bridge for Pi 5 - Feasibility check

To avoid any misunderstanding, here is the complete code for a new keymouse.c that implements the absolute position report map I posted earlier. It uses the keymouse.txt file currently on the github site, and overrides its SIZE settings by specifying the new packet lengths in write_ctic(). As an illustration it moves the cursor around a rectangle at the top left of the screen once per second. It works fine with a Windows PC.

Code:

/******** KEYMOUSE.C *********COMPILE  gcc keymouse.c btlib.c -o keymouse RUN   sudo ./keymouse********************************/#include <stdio.h>#include <stdlib.h>#include "btlib.h"  int lecallback(int clientnode,int op,int cticn);int send_key(int key);int send_mouse(int x,int y);unsigned char reportmap[100] = {0x05,0x01,0x09,0x06,0xA1,0x01,0x85,0x01,0x05,0x07,0x19,0xE0,0x29,0xE7,0x15,0x00,                               0x25,0x01,0x75,0x01,0x95,0x08,0x81,0x02,0x95,0x01,0x75,0x08,0x81,0x01,0x95,0x06,                               0x75,0x08,0x15,0x00,0x25,0x65,0x05,0x07,0x19,0x00,0x29,0x65,0x81,0x00,0xC0,                               0x05,0x01,0x09,0x02,0xA1,0x01,0x85,0x02,0x09,0x01,0xA1,0x00,0x05,0x09,0x19,0x01,                               0x29,0x03,0x15,0x00,0x25,0x01,0x95,0x03,0x75,0x01,0x81,0x02,0x95,0x01,0x75,0x05,                               0x81,0x03,0x05,0x01,0x09,0x30,0x09,0x31,0x15,0x01,0x26,0xFF,0x75,0x75,0x10,0x95,0x02,                               0x81,0x02,0xC0,0xC0};unsigned char report[8] = {0,0,0,0,0,0,0,0};unsigned char *name = "HID"; unsigned char appear[2] = {0xC1,0x03};  // 03C1 = keyboard icon appears on connecting device unsigned char pnpinfo[7] = {0x02,0x6B,0x1D,0x46,0x02,0x37,0x05};unsigned char protocolmode[1] = {0x01};unsigned char hidinfo[4] = {0x01,0x11,0x00,0x02};int main()  {  unsigned char uuid[2],randadd[6];     if(init_blue("keymouse.txt") == 0)    return(0);      if(localnode() != 1)    {    printf("ERROR - Edit keymouse.txt to set ADDRESS = %s\n",device_address(localnode()));    return(0);    }  // Write data to local characteristics  uuid[0] = 0x2A;  uuid[1] = 0x00;  write_ctic(localnode(),find_ctic_index(localnode(),UUID_2,uuid),name,3);   uuid[0] = 0x2A;  uuid[1] = 0x01;  write_ctic(localnode(),find_ctic_index(localnode(),UUID_2,uuid),appear,0);  uuid[0] = 0x2A;  uuid[1] = 0x4E;  write_ctic(localnode(),find_ctic_index(localnode(),UUID_2,uuid),protocolmode,0);  uuid[0] = 0x2A;  uuid[1] = 0x4A;  write_ctic(localnode(),find_ctic_index(localnode(),UUID_2,uuid),hidinfo,0);  uuid[0] = 0x2A;  uuid[1] = 0x4B;  write_ctic(localnode(),find_ctic_index(localnode(),UUID_2,uuid),reportmap,100);  uuid[0] = 0x2A;  uuid[1] = 0x4D;  write_ctic(localnode(),find_ctic_index(localnode(),UUID_2,uuid),report,0);  uuid[0] = 0x2A;  uuid[1] = 0x50;  write_ctic(localnode(),find_ctic_index(localnode(),UUID_2,uuid),pnpinfo,0);                              randadd[0] = 0xD3;   randadd[1] = 0x56;  randadd[2] = 0xD6;  randadd[3] = 0x74;  randadd[4] = 0x33;  randadd[5] = 0x06;  set_le_random_address(randadd);  keys_to_callback(KEY_ON,0);    set_le_wait(20000);                                            le_pair(localnode(),JUST_WORKS,0);                                         set_flags(FAST_TIMER,FLAG_ON);  le_server(lecallback,20);   close_all();  return(1);  }int lecallback(int clientnode,int op,int cticn)  {  int n,nread;  unsigned char buf[3];  static int timcount = 0;  static int absx[4] = { 100,5000,5000,100 };  static int absy[4] = { 100,100,5000,5000 };  static int xyn = 0;    if(op == LE_CONNECT)    {    printf("Connected OK\n");    timcount = 0;    }  if(op == LE_TIMER)    {    ++timcount;    if(timcount == 50)      {      send_mouse(absx[xyn],absy[xyn]);      ++xyn;      if(xyn == 4)        xyn = 0;      timcount = 0;      }    }  if(op == LE_KEYPRESS)    {  // cticn = ASCII code of key OR btferret custom code    send_key(cticn);          }  if(op == LE_DISCONNECT)    return(SERVER_EXIT);  return(SERVER_CONTINUE);  }int send_key(int key)  {  int n,hidcode;  unsigned char buf[8];  static int reportindex = -1;  // convert btferret code (key) to HID code    hidcode = hid_key_code(key);  if(hidcode == 0)    return(0);  if(reportindex < 0)    {  // look up Report1 index    buf[0] = 0x2A;    buf[1] = 0x4D;    reportindex = find_ctic_index(localnode(),UUID_2,buf);    if(reportindex < 0)      {      printf("Failed to find Report characteristic\n");      return(0);      }    }        for(n = 0 ; n < 8 ; ++n)    buf[n] = 0;          // send key press to Report1  buf[0] = (hidcode >> 8) & 0xFF;  // modifier  buf[2] = hidcode & 0xFF;         // key code  write_ctic(localnode(),reportindex,buf,0);  // send no key pressed - all zero  buf[0] = 0;  buf[2] = 0;  write_ctic(localnode(),reportindex,buf,0);   return(1);  }int send_mouse(int x,int y)  {  unsigned char buf[5];  static int reportindex = -1;     if(reportindex < 0)    {  // look up Report 1 index    buf[0] = 0x2A;    buf[1] = 0x4D;    reportindex = find_ctic_index(localnode(),UUID_2,buf);    if(reportindex < 0)      {      printf("Failed to find Report characteristic\n");      return(0);      }    ++reportindex;  // Mouse is Report 2    }        buf[0] = 0;  buf[1] = x & 0xFF;  buf[2] = (x >> 8) & 0xFF;  buf[3] = y & 0xFF;  buf[4] = (y >> 8) & 0xFF;  // send to Report2  write_ctic(localnode(),reportindex,buf,5);  return(1);  }

unsigned char reportmap[100] = {0x05, 0x01,       // Usage Page (Generic Desktop)    0x09, 0x06,       // Usage (Keyboard)    0xA1, 0x01,       // Collection (Application)    0x85, 0x01,       // Report ID (1)    0x05, 0x07,       // Usage Page (Keyboard)    0x19, 0xE0,       // Usage Minimum (Left Control)    0x29, 0xE7,       // Usage Maximum (Right GUI)    0x15, 0x00,       // Logical Minimum (0)  <-- SHOULD ALWAYS BE 0    0x25, 0x01,       // Logical Maximum (1)    0x75, 0x01,       // Report Size (1)    0x95, 0x08,       // Report Count (8)    0x81, 0x02,       // Input (Data, Variable, Absolute)    0x95, 0x01,       // Report Count (1)    0x75, 0x08,       // Report Size (8)    0x81, 0x01,       // Input (Constant)    0x95, 0x06,       // Report Count (6)    0x75, 0x08,       // Report Size (8)    0x15, 0x00,       // Logical Minimum (0)  <-- CHANGED FROM 1 TO 0    0x25, 0x65,       // Logical Maximum (101)    0x05, 0x07,       // Usage Page (Keyboard)    0x19, 0x00,       // Usage Minimum (Reserved)    0x29, 0x65,       // Usage Maximum (Keyboard Application)    0x81, 0x00,       // Input (Data, Array)    0xC0,             // End Collection       0x05, 0x01,       // Usage Page (Generic Desktop)    0x09, 0x02,       // Usage (Mouse)    0xA1, 0x01,       // Collection (Application)    0x85, 0x02,       // Report ID (2)  <-- ATTENTION SENDING THIS ID    0x09, 0x01,       // Usage (Pointer)    0xA1, 0x00,       // Collection (Physical)    0x05, 0x09,       // Usage Page (Button)    0x19, 0x01,       // Usage Minimum (Button 1)    0x29, 0x03,       // Usage Maximum (Button 3)    0x15, 0x00,       // Logical Minimum (0)    0x25, 0x01,       // Logical Maximum (1)    0x95, 0x03,       // Report Count (3)    0x75, 0x01,       // Report Size (1)    0x81, 0x02,       // Input (Data, Variable, Absolute)    0x95, 0x01,       // Report Count (1)    0x75, 0x05,       // Report Size (5)    0x81, 0x01,       // Input (Constant)    0x05, 0x01,       // Usage Page (Generic Desktop)    0x09, 0x30,       // Usage (X)    0x09, 0x31,       // Usage (Y)    0x15, 0x00,       // Logical Minimum (0)  <-- CHANGED FROM 1 TO 0    0x26, 0xFF, 0x7F, // Logical Maximum (32767)    0x75, 0x10,       // Report Size (16)    0x95, 0x02,       // Report Count (2)    0x81, 0x02,       // Input (Data, Variable, Absolute)    0xC0,             // End Collection    0xC0};

Statistics: Posted by biomekh — Tue Apr 01, 2025 4:31 am