{"id":453,"date":"2010-12-21T20:56:37","date_gmt":"2010-12-21T20:56:37","guid":{"rendered":"https:\/\/ibex.tech\/visualcpp\/?p=453"},"modified":"2022-02-17T06:24:04","modified_gmt":"2022-02-17T06:24:04","slug":"ftdi-usb-devices","status":"publish","type":"post","link":"https:\/\/ibex.tech\/visualcpp\/serial-port\/ftdi-usb-devices","title":{"rendered":"FTDI USB Devices"},"content":{"rendered":"

\nFinding Connected FTDI Devices
\n<\/h4>\n
\r\n\r\nusing namespace Microsoft::Win32;\t\t\/\/< Needed to access registry\r\n<\/code><\/pre>\n
\r\n\r\nint Count;\r\nint CharPosn;\r\nint CheckEachPortCount;\r\nString ^RegistryMainFolder;\r\nString ^SerialNumber;\r\nString ^Port;\r\narray<String^> ^FoundCommPorts = gcnew array<String^>(0);\r\narray<String^> ^FoundSerialNumbers = gcnew array<String^>(0);\r\n\r\n\/\/----- SETUP THE COMM PORT COMBO BOX -----\r\n\r\n\/\/Add the default comm port "None"\r\ncmbCommPort->Items->Add(L"None");\r\n\r\ntry\r\n{\r\n\t\/\/----- DISCOVER ALL AVAILABLE SERIAL PORTS -----\r\n\tarray<String^> ^AvailableSerialPorts;\r\n\t AvailableSerialPorts = SerialPort::GetPortNames();\r\n\r\n\t\/\/>>>>>>>>>>>>>>>> DEBUG SIMULATE COM PORT CONNECTED\r\n\t\/\/Array::Resize(AvailableSerialPorts, AvailableSerialPorts->Length + 1);\r\n\t\/\/AvailableSerialPorts[AvailableSerialPorts->Length - 1] = "COM3";\r\n\t\/\/<<<<<<<<<<<<<<<<<<<\r\n\r\n\t\/\/----- CHECK REGISTRY TO FIND MATCHING FDTI DEVICES AND ONLY INCLUDE THOSE COMM PORTS -----\r\n\t\/\/(We only show comm ports for our devices that are currently connected)\r\n\t\/\/This is the registry path we're interested in (taken from FTDI web site):-\r\n\t\/\/HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Enum\\FTDIBUS\\VID_VID+PID_PID+Serial_Number\\0000\\DeviceParameters\\PortName\r\n\r\n\t\/\/Retrieve all the subkeys for the specified key.\r\n\tRegistryMainFolder= L"SYSTEM\\\\CurrentControlSet\\\\Enum\\\\FTDIBUS";\r\n\r\n\tRegistryKey ^rkey = Registry::LocalMachine;\r\n\trkey = rkey->OpenSubKey(RegistryMainFolder);\r\n\tarray<String^>^names = rkey->GetSubKeyNames();\r\n\r\n\tfor each (String^ name in names)\r\n\t{\r\n\t\t\/\/----- CHECK NEXT FTDI DEVICE IN THE REGISTRY -----\r\n\t\t\/\/This example is based on finding only devices where the FTDI name includes a custom programmed serial number like this:\r\n\t\t\/\/name = VID_VID+PID_PID+Serial_Number\r\n\r\n\t\t\/\/Get Serial Number portion\r\n\t\tCharPosn = name->LastIndexOf("+");\r\n\t\tif (CharPosn >= 0)\r\n\t\t{\r\n\t\t\tSerialNumber = name->Substring(CharPosn + 1);\t\/\/Returns rest of string starting at character posn #\r\n\t\t\tSerialNumber = SerialNumber->Trim();\r\n\r\n\t\t\tif ((SerialNumber->Length == 7) && (SerialNumber->Contains("ABC")))\t\/\/Example test of length and contents\r\n\t\t\t{\r\n\t\t\t\trkey = Registry::LocalMachine;\r\n\t\t\t\trkey = rkey->OpenSubKey(RegistryMainFolder);\r\n\t\t\t\trkey = rkey->OpenSubKey(name);\r\n\t\t\t\trkey = rkey->OpenSubKey(L"0000\\\\Device Parameters");\r\n\t\t\t\tPort = Convert::ToString(rkey->GetValue("PortName"));\t\t\t\/\/Will be COM1 etc\r\n\r\n\t\t\t\tfor (CheckEachPortCount = 0; CheckEachPortCount < AvailableSerialPorts->Length; CheckEachPortCount++)\r\n\t\t\t\t{\r\n\t\t\t\t\tif (AvailableSerialPorts[CheckEachPortCount]->ToString() == Port->ToString())\r\n\t\t\t\t\t{\r\n\t\t\t\t\t\t\/\/THIS PORT EXISTS SO DEVICE IS CONNECTED - ADD IT TO THE ARRAY OF FOUND DEVICES\r\n\t\t\t\t\t\tArray::Resize(FoundCommPorts, FoundCommPorts->Length + 1);\r\n\t\t\t\t\t\tArray::Resize(FoundSerialNumbers, FoundSerialNumbers->Length + 1);\r\n\t\t\t\t\t\tFoundCommPorts[FoundCommPorts->Length - 1] = Port;\r\n\t\t\t\t\t\tFoundSerialNumbers[FoundSerialNumbers->Length - 1] = SerialNumber;\r\n\t\t\t\t\t\tbreak;\r\n\t\t\t\t\t}\r\n\t\t\t\t}\r\n\t\t\t}\r\n\t\t}\r\n\r\n\t}\r\n\trkey->Close();\r\n\r\n\t\/\/ADD EACH OF THE FOUND DEVICES TO THE COMM PORT COMBO BOX\r\n\tif (FoundCommPorts->Length)\r\n\t{\r\n\t\tArray::Sort(FoundCommPorts, FoundSerialNumbers);\t\t\/\/Sort by port number\r\n\r\n\t\tfor (Count = 0; Count < FoundCommPorts->Length; Count++)\r\n\t\t{\r\n\t\t\tcmbCommPort->Items->Add(FoundCommPorts[Count] + \" (Serial #: \" + FoundSerialNumbers[Count]->Substring(4, 4) + ")");\r\n\t\t}\r\n\r\n\t}\r\n}\r\ncatch(System::Exception^ e)\r\n{\r\n\r\n}\r\n<\/code><\/pre>\n
\nSetting Latency Of FTDI Devices
\n<\/h4>\n
\r\n\r\n\/\/----- CHECK LATENCY SETTINGS OF FTDI COM PORTS FOR OUR DEVICE -----\r\n\/\/FTDI latency is the time from receiving the last byte before the packet is sen't via USB\r\n\/\/It is 16mS defualt, we want it as fast as possible and FTDI recomends a min value of 2mS (not 1mS)\r\n\/\/Check each of the FTDI ports that is used by our device and modify the value if need be.  On Windows\r\n\/\/Vista and above access permission will not be given by UAC so a message box is displayed informing the user they need to use 'Run As\r\n\/\/Administrator' to allow the applicaiton to update the registry.  To do this they need to log on as an administrator rights user,\r\n\/\/find the application executible in windows explorer, right click and select run as administrator.  Alternatively the values could\r\n\/\/be edited in regedit.\r\n\/\/Tested after setting to 2 and it woudl take between 1mS and 3mS for for the next packet to be sent, implying that the timer in the\r\n\/\/FDTI chip is literally a 1mS incrementing timer, hence the min value of 2mS being recomended.\r\n\r\nint CharPosn;\r\nString ^RegistryMainFolder;\r\nString ^SerialNumber;\r\nint Latency;\r\nstatic bool NotifiedUserCantWriteRegistry = false;\r\n\r\ntry\r\n{\r\n\t\/\/----- CHECK REGISTRY TO FIND FDTI DEVICES -----\r\n\t\/\/Retrieve all the subkeys for the specified key.\r\n\tRegistryMainFolder= L"SYSTEM\\\\CurrentControlSet\\\\Enum\\\\FTDIBUS";\t\t\/\/FTDI Path:- HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Enum\\FTDIBUS\\VID_VID+PID_PID+Serial_Number\\0000\\DeviceParameters\\\r\n\r\n\tRegistryKey ^rkey = Registry::LocalMachine;\r\n\trkey = rkey->OpenSubKey(RegistryMainFolder);\r\n\tarray<String^>^names = rkey->GetSubKeyNames();\r\n\r\n\tfor each (String^ name in names)\r\n\t{\r\n\t\t\/\/----- CHECK NEXT FTDI DEVICE IN THE REGISTRY -----\r\n\t\t\/\/name = VID_VID+PID_PID+Serial_Number\r\n\r\n\t\t\/\/Out device has a serial number programmed that always begins with "ABC" so look for it\r\n\r\n\t\t\/\/Get Serial Number\r\n\t\tCharPosn = name->LastIndexOf("+");\r\n\t\tif (CharPosn >= 0)\r\n\t\t{\r\n\t\t\tSerialNumber = name->Substring(CharPosn + 1);\t\/\/Returns rest of string starting at character posn #\r\n\r\n\t\t\tif (SerialNumber->Contains("ABC"))\t\t\t\/\/<<<<<< SET STRING TO LOOK FOR IN SERIAL NUMBER\r\n\t\t\t{\r\n\t\t\t\t\/\/THIS IS OUR PRODUCT\r\n\t\t\t\trkey = Registry::LocalMachine;\r\n\t\t\t\trkey = rkey->OpenSubKey(RegistryMainFolder);\r\n\t\t\t\trkey = rkey->OpenSubKey(name);\r\n\t\t\t\trkey = rkey->OpenSubKey(L"0000\\\\Device Parameters");\r\n\r\n\t\t\t\t\/\/CHECK IF WE NEED TO CHANGE THE LATENCY TIMER VALUE\r\n\t\t\t\tLatency = Convert::ToInt32(rkey->GetValue("LatencyTimer"));\r\n\t\t\t\tif (Latency != 2)\t\t\t\t\t\t\/\/<<<<<<< LATENCY VALUE REQUIRED\r\n\t\t\t\t{\r\n\t\t\t\t\trkey = rkey->OpenSubKey("", true);\t\/\/Open as writable\r\n\t\t\t\t\trkey->SetValue("LatencyTimer", 2);\t\/\/<<<<<<< LATENCY VALUE REQUIRED\r\n\t\t\t\t}\r\n\t\t\t}\r\n\t\t}\r\n\t}\r\n\trkey->Close();\r\n}\r\ncatch(System::Exception^ e)\r\n{\r\n\tif (!NotifiedUserCantWriteRegistry)\r\n\t\tMessageBox::Show(L"Unable to modify FTDI latency parameters in Windows registry.\\nUSB communications will be slower than normal.\\nUse 'Run As Administrator' to allow application to set the required values", L"Need admin permissions", MessageBoxButtons::OK, MessageBoxIcon::Exclamation);\r\n\tNotifiedUserCantWriteRegistry = true;\r\n}\r\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
Finding Connected FTDI Devices using namespace Microsoft::Win32; \/\/< Needed to access registry int Count; int CharPosn; int CheckEachPortCount; String ^RegistryMainFolder; String ^SerialNumber; String ^Port; array<String^> ^FoundCommPorts = gcnew array<String^>(0); array<String^> ^FoundSerialNumbers = gcnew array<String^>(0); \/\/—– SETUP THE COMM PORT COMBO BOX —– \/\/Add the default comm port "None" cmbCommPort->Items->Add(L"None"); try { \/\/—– DISCOVER ALL AVAILABLE […]<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[57],"tags":[],"class_list":["post-453","post","type-post","status-publish","format-standard","hentry","category-serial-port"],"_links":{"self":[{"href":"https:\/\/ibex.tech\/visualcpp\/wp-json\/wp\/v2\/posts\/453","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ibex.tech\/visualcpp\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ibex.tech\/visualcpp\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ibex.tech\/visualcpp\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/ibex.tech\/visualcpp\/wp-json\/wp\/v2\/comments?post=453"}],"version-history":[{"count":3,"href":"https:\/\/ibex.tech\/visualcpp\/wp-json\/wp\/v2\/posts\/453\/revisions"}],"predecessor-version":[{"id":1077,"href":"https:\/\/ibex.tech\/visualcpp\/wp-json\/wp\/v2\/posts\/453\/revisions\/1077"}],"wp:attachment":[{"href":"https:\/\/ibex.tech\/visualcpp\/wp-json\/wp\/v2\/media?parent=453"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ibex.tech\/visualcpp\/wp-json\/wp\/v2\/categories?post=453"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ibex.tech\/visualcpp\/wp-json\/wp\/v2\/tags?post=453"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}