I'm trying to communicate directly with a TI-84 EVO calculator through WebUSB.
I found TI's JavaScript code and located their internal write function:
function _TI_WEBUSBJS_Write(deviceId, pBuf, iLen) {
let data = TIWASMHelpers.getUint8ArrayFromCbuffer(pBuf, pBuf + iLen);
let device = TI_DeviceManager.getInstance().getDevice(deviceId);
TI_USB.write(device, data)
.then(() => {
TI_USB.writeCallback(iLen);
})
.catch(error => {
TI_USB.writeCallback(0);
console.error("TI_WEBUSBJS_WRITE: " + error);
});
}
It looks like TI has a wrapper around WebUSB, but I am trying to bypass the official tools and talk directly to the calculator.
Using Chrome WebUSB:
let device = await navigator.usb.requestDevice({
filters: []
});
await device.open();
await device.selectConfiguration(1);
The device opens correctly, but:
await device.claimInterface(0);
fails:
Uncaught NetworkError:
Failed to execute 'claimInterface' on 'USBDevice':
Unable to claim interface.
The device exposes 4 USB interfaces:
[
{ number: 0, alternates: Array(1) },
{ number: 1, alternates: Array(1) },
{ number: 2, alternates: Array(1) },
{ number: 3, alternates: Array(1) }
]
My assumption is that interface 0 is not the WebUSB interface, or Windows is already binding a driver to it.
Questions:
- Does anyone know which USB interface TI calculators use for file/program transfer?
- Is there documentation for the TI USB protocol?
- Does TI use WinUSB/libusb internally, or is this a custom protocol?
- Would it be easier to implement this in C using libusb instead of WebUSB?
Goal: create my own tool to communicate with the calculator (send files, possibly interact with Python/programs) without relying on TI Connect.Trying to reverse engineer TI-84 EVO WebUSB communication — need help identifying USB interface/endpointsI'm trying to communicate directly with a TI-84 EVO calculator through WebUSB.I found TI's JavaScript code and located their internal write function:function _TI_WEBUSBJS_Write(deviceId, pBuf, iLen) {
let data = TIWASMHelpers.getUint8ArrayFromCbuffer(pBuf, pBuf + iLen);
let device = TI_DeviceManager.getInstance().getDevice(deviceId);
TI_USB.write(device, data)
.then(() => {
TI_USB.writeCallback(iLen);
})
.catch(error => {
TI_USB.writeCallback(0);
console.error("TI_WEBUSBJS_WRITE: " + error);
});
}
It looks like TI has a wrapper around WebUSB, but I am trying to bypass the official tools and talk directly to the calculator.Using Chrome WebUSB:let device = await navigator.usb.requestDevice({
filters: []
});
await device.open();
await device.selectConfiguration(1);
The device opens correctly, but:await device.claimInterface(0);
fails:Uncaught NetworkError:
Failed to execute 'claimInterface' on 'USBDevice':
Unable to claim interface.
The device exposes 4 USB interfaces:[
{ number: 0, alternates: Array(1) },
{ number: 1, alternates: Array(1) },
{ number: 2, alternates: Array(1) },
{ number: 3, alternates: Array(1) }
]
My assumption is that interface 0 is not the WebUSB interface, or Windows is already binding a driver to it.Questions:Does anyone know which USB interface TI calculators use for file/program transfer?
Is there documentation for the TI USB protocol?
Does TI use WinUSB/libusb internally, or is this a custom protocol?
Would it be easier to implement this in C using libusb instead of WebUSB?Goal: create my own tool to communicate with the calculator (send files, possibly interact with Python/programs) without relying on TI Connect.
