[arisov77]

Continue Subjects http://www.cnczone.com/forums/showthread.php?t=62911 here, as this open project and i hope that who be else joined to modernizations Elm Chan servocontroller.
Present new variant scheme and code.
Change:
- Moved converter RS-232/UART from PCB into DataCable. USB/UART on FT232 - works, but bad. Better use RS232/UART.
- Added limit move Limit_L & Limit_R. Questioning of their condition through 20ms (for eliminating noise). If Limit are not used, that detail their chain possible not to install. Internal pull-ups resistors to all input are installed software in AtMega.
- Select type contact (Normally closed or normally open)
- Input EMERGENCY STOP (E-Stop) - it is actuated one temporarily enable Limit_L & Limit_R to condition “ServoError”.
- Output “ServoError”. Moves over to condition “ServoError” with simultaneous indication of this condition. Disable thereof conditions through Off-On power, unset on Reset or in ServoTuning push “Stop” or change the mode.
- Two steps of protection from unbalance of the positions. 1st. - at excess 20 000 steps immediately transition in condition “ServoError” . 2st. - on time - at excess 3 steps are included timer and if in current 15 seconds unbalance will not become less 3 steps, that transition in condition “ServoError”. If for 15 sec. unbalance will become less 3 steps, that timer reset.
- Sensing the condition encoder possible (as variant) on interruptions from internal comparator. On him and external entities VD2,VD3, R23-R25, R29 is made analog exclusive or (EOR). The differences in work I have not noticed (no high-resolution encoder), but theoretically she better (fast), than with questioning encoder on interruption from Timer0 (12mks).
- It is actuated WatchDog (period 38ms)
- Increased reliability of keeping data in EEPROM. For this: record of each parameter from ServoTuning is produced in 3 bytes located in miscellaneous area EEPROM. At power-up are read these 3 bytes, are then compared and if one of them is not others, that is produced rerecording the bad cell. This is repeated for all importances in EEPROM. When loading parameter from EEPROM in ServoTuning are read given only from one area (without checking for equality). After conservation and loading parameter address EEPROM is changed on address not containing data. After these change - I reset EEPROM did not observe.

I have done 4 variant Source Code: Servo_AtMega_TimerInt - for AtMega8, on Timer, Servo_AtMega_CompInt – for AtMega8, on comparator and such for AtMega88 - Servo_AtMega88_TimerInt and Servo_AtMega88_CompInt. The Code trims with interruptions from Timer0 possible to use as with scheme, which I shown earlier, so and new variant. With interruptions from comparator, only with new variant of the scheme. The Code trim with interruptions from compator I have checked only with AtMega88, with AtMega8 only partly, but guarantee on 95% that she will work.

When adjusting in ServoTuning importances for Your motor save in zero bank, as started with it.

Possible ways of the further improvement:
- Installing the quartz on 24МГц and change the program
- Use the hardware multiplying (only on AtMega)
- Change of time of the servo cycle with 1ms on more low importance
- Development PCB. Since I all change did on PCB, which shown earlier + with additional element with outboard montage.

Commentary in Source Code in russian language, but if it is necessary can translate one of the SourceCodes (for example).