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+history
+-------
+
+11.9.2020
+- ordered set at eater.net
+
+23.10.2020:
+- started the clock module, finish 24.10. morning
+
+24.10.2020:
+nops and introspection using Arduino Mega 2560
+sadly Archlinux32 arduino builder (avr gcc) segfaults, needs investigation
+(on 64-bit for now)
+started to struggle with the EEPROM programmer and minipro, ok in the end
+thoughts on using cheap 2k ROMs first instead of the 32k ROM
+
+25.10.2020:
+managed to program 2k EPROM, also able to set reset vector and start
+PROM software at f800
+
+27.10.2020:
+VIA chip works with blinken lights
+
+28.10.2020:
+broken clock (a missing ground with funny effects on the CLK line)
+another light example (counter)
+
+29.10.2020:
+working rom-only LCD display
+
+30.10.2020:
+added ram for zero page and call stack (just A0-A8, left all others
+floating with nice effects!), working LCD example with subroutines
+and RAM.
+
+1.11.2020:
+playing with interrupts
+clear memory
+strange memory test, write 255 zeroes to zero page, read, bne,
+getting distorted output (though we are not using ram!)
+VIA IRQ handling with capacitance cheapo debouncer on interrupt button.
+
+2.11.2020:
+soldered a pin to the broken EPPROM, works :-)
+playing with I/O peripherial data bus
+zif dry for broken EEPROM, works fine
+
+3.11.2020:
+new parts order
+
+4.11.2020:
+new parts order (check)
+some thinking on transistors for feeding two LEDs from on PROM
+
+5.11.2020:
+new breadboard
+did the 2-digit 7-segment display, currently unbuffered on the
+I/O data bus
+
+6.11.2020:
+shift register for 7-bit output via the VIA
+opcode decoding (from Ben Eaters 6502 monitor project)
+almost working counter with reset (on IRQ)
+found a bug in encoding of hex 'C' (which means, redo the thing)
+
+7.11.2020:
+fixed 'C' in 7-digit EEPROM
+stange BRK interrupts and RTIs to strange addresses -> floating
+address lines on RAM (again!), IRQ on VIA has to be acknowledged,
+otherwise it triggers constantly (so the counter seems to stop).
+playing with delays to make counter work correctly (somewhat).
+
+
+8.11.2020:
+using via timer1 for 10ms ticks, time counter increment instead of delay
+weird issue with TICK on $1 and COUNTER on $0, works fine with TICK $10,
+so again, a SRAM issue?
+working more on a SRAM test
+ordered SRAM at Reichelt, waiting
+
+11.11.2020:
+VGA kit arrived, some weird issues with payment (UPS, as usual)
+
+17.11.2020:
+new RAM, same problems
+VCC on counters stabilize the circuit on slow clock
+
+commands
+--------
+
+xxd -r rom.hex > rom.bin
+hexdump -C rom.bin
+minipro -w rom.bin -p AT28C16@DIP24
+minipro -m rom.bin -p AT28C16@DIP24
+minipro -r x -p AT28C16@DIP24
+cmp x rom.bin
+
+# -wdc02 for extensions
+vasm6502_oldstyle -wdc02 -x -wfail -chklabels -dotdir -o rom.bin -Fbin rom.asm
+