diff --git a/Home.md b/Home.md index b1abe18..70567a7 100644 --- a/Home.md +++ b/Home.md @@ -8,6 +8,7 @@ This wiki will collect technical notes, assembly and configuration guides, tips [Apple II notes](apple-ii-notes) +[Encoder nodes (2560-based)](encoder-2560-notes)
Programming the Atmega chips 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) @@ -30,5 +31,18 @@ All other fuses disabled.
For ATMega2560 -TO DO +Extended: 0xFF +High: 0x99 +Low: 0xE7 + +This corresponds to the following fuse settings + +- Brownout Detection Disabled (Extended byte) +- JTAGEN (in system programming over JTAG) Enabled (High byte) +- SPIEN (in system programming over SPI) Enabled (High byte) +- Boot flash size 4096 ((high byte) +- Full Swing Oscillator, xtal, fast rise, 4.1 ms startup (low byte) + +All other fuses disabled. +
diff --git a/encoder-2560-notes/encoder-2560-notes.md b/encoder-2560-notes/encoder-2560-notes.md new file mode 100644 index 0000000..2df24da --- /dev/null +++ b/encoder-2560-notes/encoder-2560-notes.md @@ -0,0 +1,23 @@ +Fuse settings for the ATMega2560: + +Extended: 0xFF +High: 0x99 +Low: 0xE7 + +This corresponds to the following fuse settings + +- Brownout Detection Disabled (Extended byte) +- JTAGEN (in system programming over JTAG) Enabled (High byte) +- SPIEN (in system programming over SPI) Enabled (High byte) +- Boot flash size 4096 ((high byte) +- Full Swing Oscillator, xtal, fast rise, 4.1 ms startup (low byte) + +All other fuses disabled. + +Errata: + +
rev 4.2: +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. + +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. +