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break out separate section for 2560 encoder.
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Home.md
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Home.md
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@ -8,6 +8,7 @@ This wiki will collect technical notes, assembly and configuration guides, tips
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[Apple II notes](apple-ii-notes)
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[Apple II notes](apple-ii-notes)
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[Encoder nodes (2560-based)](encoder-2560-notes)
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<details>
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<details>
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<summary>Programming the Atmega chips</summary>
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<summary>Programming the Atmega chips</summary>
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Make sure that the DIV8 flag is OFF (or the chip will run at 1 MHz and you will find the encoder to be very sluggish), and the ISP programming flag is enabled (if you want to be able to program via the ISP header)
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Make sure that the DIV8 flag is OFF (or the chip will run at 1 MHz and you will find the encoder to be very sluggish), and the ISP programming flag is enabled (if you want to be able to program via the ISP header)
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@ -30,5 +31,18 @@ All other fuses disabled.
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</details>
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</details>
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<details><summary>For ATMega2560</summary>
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<details><summary>For ATMega2560</summary>
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TO DO
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Extended: 0xFF
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High: 0x99
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Low: 0xE7
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This corresponds to the following fuse settings
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- Brownout Detection Disabled (Extended byte)
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- JTAGEN (in system programming over JTAG) Enabled (High byte)
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- SPIEN (in system programming over SPI) Enabled (High byte)
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- Boot flash size 4096 ((high byte)
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- Full Swing Oscillator, xtal, fast rise, 4.1 ms startup (low byte)
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All other fuses disabled.
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</details>
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</details>
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23
encoder-2560-notes/encoder-2560-notes.md
Normal file
23
encoder-2560-notes/encoder-2560-notes.md
Normal file
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@ -0,0 +1,23 @@
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Fuse settings for the ATMega2560:
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Extended: 0xFF
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High: 0x99
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Low: 0xE7
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This corresponds to the following fuse settings
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- Brownout Detection Disabled (Extended byte)
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- JTAGEN (in system programming over JTAG) Enabled (High byte)
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- SPIEN (in system programming over SPI) Enabled (High byte)
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- Boot flash size 4096 ((high byte)
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- Full Swing Oscillator, xtal, fast rise, 4.1 ms startup (low byte)
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All other fuses disabled.
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Errata:
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<details><summary>rev 4.2:</summary>
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The footprints for D1-D16 are supposed to have a shorting jumper trace built in. For keyboards with a diode installed per-key, these diodes are not installed. Since the jumpers are not pre-configured, wire jumpers must be installed in the D1-D16 positions for the keyboard to scan correctly.
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If you are using a keyboard without any built-in diodes (such as a prefabricated key matrix), then install the diodes D1-D16 (1n914, in4148, or similar) to protect the row-scanning TTL outputs from conflicting logic levels in the event of simultaneous keypresses.
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</details>
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