reprap:anet:anet_mainboard_overclocking

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reprap:anet:anet_mainboard_overclocking [2018/01/04 15:37] – [Marlin changes] gmarsh23reprap:anet:anet_mainboard_overclocking [2018/01/09 04:14] – [Crystal selection and replacement] gmarsh23
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 === Choosing a new crystal === === Choosing a new crystal ===
  
-The Anet V1.0 board requires a "HC-49S" surface mount crystal. Choose one with an 18 to 22pF load capacitance, as this best matches the load capacitance provided on the Anet board.+The Anet V1.0 board requires a "HC-49S" surface mount crystal. Choose one with a 12pf load capacitance, as this best matches the load capacitance provided on the Anet board.
  
 Here are some suitable crystal frequencies to choose from: Here are some suitable crystal frequencies to choose from:
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 | 27MHz | +68.8% | +35% | May be unstable.\\ significant baud rate error (see below)\\ Can be salvaged from video equipment (DVD players, etc) | | 27MHz | +68.8% | +35% | May be unstable.\\ significant baud rate error (see below)\\ Can be salvaged from video equipment (DVD players, etc) |
  
-If you're using the USB interface of the printer, using Octoprint for example, the crystal you choose affects how accurate the baud rate of the Mega1284P's UART will be at a given baud rate. For reliability reasons this should not exceed +-5%; ideally this value is less than +-2.5%. If you only printing from the SD card, this isn't an issue.+Note: If you're using the USB interface of the printer, using Octoprint for example, the crystal you choose affects how accurate the baud rate of the Mega1284P's UART will be at a given baud rate. For reliability reasons this should not exceed +-5%; ideally this value is less than +-2.5%. If you don't plan on using the printer's USB connection, this isn't an issue.
  
-MHz (below), baud (right) ^ 115200 ^ 230400 ^ 250000 ^ 460800 ^ 500000 ^ 921600 ^ 1000000 ^ 1500000 ^ +Crystal freq (below), baud (right) ^ 115200 ^ 230400 ^ 250000 ^ 460800 ^ 500000 ^ 921600 ^ 1000000 ^ 1500000 ^ 
-16 | 2.1% | -3.5% | 0% | 8.5% | 0% | 8.5% | 0% | 33% | +16MHz | 2.1% | -3.5% | 0% | //8.5%// | 0% | //8.5%// | 0% | //33%// 
-20 | -1.4% | -1.4% | 0% | 8.5% | 0% | -9.6% | -16.7% | -16.7% | +20MHz | -1.4% | -1.4% | 0% | //8.5%// | 0% | //-9.6%// //-16.7%// //-16.7%// 
-24 | 0.16% | 0.16% | 0% | -7.0% | **0%** | 8.5% | 0% | 0% | +24MHz | 0.16% | 0.16% | 0% | //-7.0%// | **0%** | //8.5%// | 0% | 0% | 
-25 | 0.5% | -3.1% | -3.8% | -3.1% | 4.2% | 13% | 4.2% | 4.2% | +25MHz | 0.5% | -3.1% | -3.8% | -3.1% | 4.2% | //13%// | 4.2% | 4.2% | 
-27 | 1% | -2.3% | -3.6% | 4.6% | -3.6% | 8.4% | 12.5% | 12.5% |+27MHz | 1% | -2.3% | -3.6% | 4.6% | -3.6% | //8.4%// //12.5%// //12.5%// |
  
 To calculate for different clock frequencies and baud rates, use the following math: To calculate for different clock frequencies and baud rates, use the following math:
  
-  * UART divisor = (Processor clock) / 8 / Desired baud rate +  * UART divisor = crystal frequency / 8 / Desired baud rate 
-  * Actual baud rate = (Processor clock) / 8 / rounded divisor value+  * Actual baud rate = crystal frequency / 8 / rounded divisor value
   * Actual baud rate and desired baud rate should be +-5%, preferably +-2.5%   * Actual baud rate and desired baud rate should be +-5%, preferably +-2.5%
  
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 === Downloading and compiling Optiboot === === Downloading and compiling Optiboot ===
 +
 +**If you're using a 24MHz crystal, just copy this paste and save it as a .hex file:** https://pastebin.com/Tv1EHPmc
  
 You'll need to download and compile Optiboot first. More information can be found on the Optiboot github page: https://github.com/Optiboot/optiboot/wiki/CompilingOptiboot You'll need to download and compile Optiboot first. More information can be found on the Optiboot github page: https://github.com/Optiboot/optiboot/wiki/CompilingOptiboot
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 Use the following options to compile it for the Anet V1.0 board. Change the "24000000" value to the frequency of the crystal you're using in Hz - don't forget the L on the end.  Use the following options to compile it for the Anet V1.0 board. Change the "24000000" value to the frequency of the crystal you're using in Hz - don't forget the L on the end. 
  
-  make AVR_FREQ=24000000L BAUD_RATE=57600 LED=A4 atmega1284p UART=0+  make AVR_FREQ=24000000L BAUD_RATE=57600 LED=A4 UART=0 atmega1284p
  
 Save the .hex file for later. Save the .hex file for later.
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 === Flashing new firmware === === Flashing new firmware ===
  
-Use AVRDUDE:+Use AVRDUDE to set the fuse/lockbit values on the processor, then program in the new bootloader: 
 + 
 +  avrdude -p atmega1284p -c <your programmer> -U hfuse:w:0xDE:m lfuse:w:0xf7:m efuse:w:0xfc:m lock:w:0x2f:
 +  avrdude -p atmega1284p -c <your programmer> -U flash:w:optiboot_atmega1284p.hex
  
-  avrdude -p atmega1284p -c <your programer> -U flash:w:optiboot_new.hex+The fuse values given move the bootloader start address to 0xFE00/0x1FC00 (word/byte) which frees up 3K of application space from the bootloader section. The lock bits prevent the bootloader from overwriting itself and bricking the board, if you send in a code image which is big enough to expand into the bootloader space.
  
 Once the board is programmed, connect the board to your PC via its USB connection, and attempt to "ping" the new bootloader with the following avrdude command. Change "COM1" to the serial port corresponding to the printer on your computer. Once the board is programmed, connect the board to your PC via its USB connection, and attempt to "ping" the new bootloader with the following avrdude command. Change "COM1" to the serial port corresponding to the printer on your computer.
  • reprap/anet/anet_mainboard_overclocking.txt
  • Last modified: 2018/12/02 02:27
  • by 127.0.0.1