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| web-u2 [2019/09/09 16:28] – remove support kingkevin | web-u2 [2019/09/09 18:18] – [USB HID] kingkevin |
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| ==== USB HID ==== | ==== USB HID ==== |
| |
| | When connected to USB, it appears as an {{ :u2:usb_hid.txt |HID}} (Human Interface Device).\\ |
| | When powered while pressing on the OK button, it will boot in the DFU (Device Firmware Upgrade) mode, which allows flashing the firmware. |
| | But it is still an {{ :u2:usb_dfu.txt |HID}}, and does not use the DFU profile specified by USB. |
| | |
| | I've partially reversed the HID communication: |
| | * the messages exchanged are 64 bytes long |
| | * the host (e.g. software) starts by sending a message. Here an example of message sent (captured from the software): |
| | <code> |
| | "\xff\x55\x58\x8a\x13\x79\x06\x57\x1a\x01\x0a\x02\x00\x00\x00\x00" \ |
| | "\x5e\x00\x00\x00\xff\x55\x2f\xb2\x8b\xdc\x5a\xd4\x1a\x2c\xa4\x00" \ |
| | "\xa4\x40\x00\x00\x00\x00\x00\x00\x00\x00\x0e\x74\x21\x4f\x40\x75" \ |
| | "\x23\x19\x40\x75\xcc\x01\x01\x00\x02\x04\x00\x00\x5e\x00\xe7\x06"; |
| | </code> |
| | * this will cause the device (e.g. U2) to send measurements. Since it will only send a couple of messages, keep sending the message every couple of milliseconds (can be the same). Here an example measurement reply: |
| | <code> |
| | ff 55 13 b4 7f bf 50 ef 1a 2c d7 63 a0 40 0e 74 da 39 0e 74 da 39 0e 74 da 39 bb dd 08 3b 33 33 53 40 74 a8 6d 3c fe 98 f7 41 d2 34 91 c2 14 ae a0 40 0e 74 da 39 00 00 00 00 00 00 00 00 16 ae |
| | </code> |
| | |
| | here how to decode the measurements: |
| | ^ index ^ byte(s) ^ format ^ meaning ^ |
| | | 0-1 | ''ff 55'' | constant | probably a fixed header | |
| | | 2 | ''13'' | integer | number of second | |
| | | 3 | ''b4'' | integer | super fast incrementing number (but not related to other bytes) | |
| | | 4 | ''7f'' | integer | fast incrementing number (but not related to other bytes) | |
| | | 5 | ''bf'' | integer | incrementing number (but not related to other bytes) | |
| | | 6 | ''50'' | integer | 1/100th of byte 5 | |
| | | 7 | ''ef'' | integer | slow incrementing number (but not related to other bytes) | |
| | | 8-9 | ''1a 2c'' | constant | separates timing form measurement values | |
| | | 10-13 | ''d7 63 a0 40'' | float | VBUS voltage, in V (e.g. 5.0122 V) | |
| | | 14-17 | ''0e 74 da 39'' | float | VBUS current, in A (e.g. 0.0004 A) | |
| | | 18-21 | ''0e 74 da 39'' | float | VBUS current, in A (seems the same as previous current) | |
| | | 22-25 | ''0e 74 da 39'' | float | VBUS current, in A (sometimes slightly different for the other values, but I don't know why) | |
| | | 26-29 | ''bb dd 08 3b'' | float | VBUS power, in W (e.g. 0.0021 W ) | |
| | | 30-33 | ''33 33 53 40'' | float | D+ voltage, in V (e.g. 3.3000 V) | |
| | | 34-37 | ''74 a8 6d 3c'' | float | D- voltage, in V (e.g. 0.0145 V) | |
| | | 38-41 | ''fe 98 f7 41'' | float | In temperature (internal), in °C (e.g. 30.95 °C) | |
| | | 42-45 | ''d2 34 91 c2'' | float | Ex temperature (external, from IN Micro-USB probe), in °C (e.g. -72.60 °C, because not connected) | |
| | | 46-49 | ''14 ae a0 40'' | float | VBUS voltage (differs from first value, but I don't know how), in V (e.g. 5.0212 V) | |
| | | 50-53 | ''0e 74 da 39'' | float | VBUS current (sometimes slightly different for the other values, but I don't know why), in A (e.g. 0.0004 A) | |
| | | 54-61 | ''00 00 00 00 00 00 00 00'' | constant | seems always 0 | |
| | | 62 | ''16'' | integer | checksum (addition of bytes 8-61) | |
| | | 63 | ''ae'' | integer | checksum (addition of bytes 0-61) | |
| | |
| | There are other messages to get the device's serial number and firmware version, but I did not reverse those. |
| ==== Bluetooth Serial ==== | ==== Bluetooth Serial ==== |
