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Both sides previous revision Previous revision Next revision | Previous revision Next revisionBoth sides next revision | ||
reprap:anet:anet_mainboard_overclocking [2018/01/04 15:37] – [Marlin changes] gmarsh23 | reprap:anet:anet_mainboard_overclocking [2018/01/04 15:41] – [Crystal selection and replacement] gmarsh23 | ||
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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' | 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' | ||
- | ^ 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) | + | * UART divisor = crystal frequency |
- | * Actual baud rate = (Processor clock) | + | * Actual baud rate = crystal frequency |
* 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% | ||