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| ID | Project | Category | View Status | Date Submitted | Last Update | ||||
|---|---|---|---|---|---|---|---|---|---|
| 0000015 | HomeAutomation System | General | public | 2012-08-01 23:27 | 2012-08-12 14:56 | ||||
| Reporter | Anders Sandblad | ||||||||
| Assigned To | Anders Sandblad | ||||||||
| Priority | normal | Severity | minor | Reproducibility | always | ||||
| Status | closed | Resolution | fixed | ||||||
| Summary | 0000015: Speed up USB gateway | ||||||||
| Description | 1. Baudrates. 1Mb/s > 38400b/s 2. Uart double speed, may make it possible to go for 56kb/s or even 115kb/s 3. Lower FTDI latency to 1ms, see additional information 4. Fill FTDI buffer of 62 bytes to force sending Implementing 1 may need implementing 4 since 1ms will make a big impact otherwise. | ||||||||
| Additional Information | http://www.spinics.net/lists/linux-usb/msg37973.html /sys/bus/usb-serial/devices/ttyUSB0/latency_timer ASYNC_LOW_LATENCY flag http://projectgus.com/2011/10/notes-on-ftdi-latency-with-arduino/ http://stackoverflow.com/questions/10718693/set-low-latency-flag-on-a-serial-port-on-windows-in-c http://arduino.cc/forum/index.php?topic=96.0 | ||||||||
| Tags | No tags attached. | ||||||||
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| Notes |
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Anders Sandblad (administrator) 2012-08-02 20:48 |
Uncomment the following line in config.h to test UART DOUBLE SPEED according 2. above. #define SERIAL_DOUBLE_SPEED 1 |
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Anders Sandblad (administrator) 2012-08-02 21:13 |
With SERIAL_DOUBLE_SPEED active a speed of 76800 can be reached with an error of 0.2% (same error as 38400). 250k, 500k and 1M can be reached with an error of 0% but for 1M SERIAL_DOUBLE_SPEED must be active. |
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Anders Sandblad (administrator) 2012-08-02 21:59 |
Tests with baudrate of 1Mb/s gives about 900b/s at reprogramming (not scientific measured). |
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Anders Sandblad (administrator) 2012-08-02 22:09 |
Changed default baudrate to 1Mb/s and activated SERIAL_DOUBLE_SPEED with http://websvn.auml.se/HomeAutomation/?op=revision&rev=2151 |
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Anders Sandblad (administrator) 2012-08-02 22:37 |
More optimization is possible but current fix is good enough. |
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Anders Sandblad (administrator) 2012-08-12 14:56 |
Closing after verifying that 1Mbit/s works. More optimization possible but unnecessary. Open again or create new issue if needed. |
| Notes |
| Issue History |
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| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2012-08-01 23:27 | Anders Sandblad | New Issue | |
| 2012-08-02 20:48 | Anders Sandblad | Note Added: 0000013 | |
| 2012-08-02 21:13 | Anders Sandblad | Note Added: 0000014 | |
| 2012-08-02 21:59 | Anders Sandblad | Note Added: 0000015 | |
| 2012-08-02 22:09 | Anders Sandblad | Note Added: 0000016 | |
| 2012-08-02 22:37 | Anders Sandblad | Note Added: 0000017 | |
| 2012-08-02 22:37 | Anders Sandblad | Status | new => resolved |
| 2012-08-02 22:37 | Anders Sandblad | Resolution | open => fixed |
| 2012-08-02 22:37 | Anders Sandblad | Assigned To | => Anders Sandblad |
| 2012-08-12 14:56 | Anders Sandblad | Note Added: 0000023 | |
| 2012-08-12 14:56 | Anders Sandblad | Status | resolved => closed |
| Issue History |