Add improved silkscreen, DigiKey BOM, Linux build script and update README

6button-MegaDrive-controller-PCB-DigiKey-BOM.csv

@@ -0,0 +1,8 @@
+Digi-Key Part Number,Quantity,Reference,Value,Manufacturer,Manufacturer Product Number,Description,Datasheet
+478-KGM21NR71H104KTCT-ND,10,"C1,C2,C3",0.1u,KYOCERA AVX,KGM21NR71H104KT,CAP CER 0.1UF 50V X7R 0805 – Only 3 needed but cheaper to buy 10 than 3,~
+A122908-ND,1,J1,CONN HEADER VERT 14POS 2.54MM,TE Connectivity AMP Connectors,826632-7,"Connector Header Through Hole 14 position 0.100"" (2.54mm)",~
+2057-PH1-09-UA-ND,1,J2,CONN HEADER VERT 9POS 2.54MM,Adam Tech,PH1-09-UA,"Connector Header Through Hole 9 position 0.100"" (2.54mm)",~
+2057-BHR-06-VUA-ND,1,J3,CONN HEADER VERT 6POS 2.54MM,Adam Tech,BHR-06-VUA,"Connector Header Through Hole 6 position 0.100"" (2.54mm)",~
+A102341CT-ND,12,"R1,R2,R3,R4,R5,R6,R7,R8,R9,R10,R11,R12",75k,TE Connectivity Passive Product,CPF0805B75KE1,"75 kOhms ±0.1% 0.1W, 1/10W Chip Resistor 0805 (2012 Metric) Thin Film",~
+296-CD74HC257M96CT-ND,2,"U1,U3",74HC257,Texas Instruments,CD74HC257M96,Multiplexer 4 x 2:1 16-SOIC,http://www.ti.com/lit/gpn/sn74LS257
+ATTINY404-SSNRCT-ND,1,U2,ATTINY404-SSNR,Microchip Technology,ATTINY404-SSNR,"AVR tinyAVR™ 0, Functional Safety (FuSa) Microcontroller IC 8-Bit 20MHz 4KB (4K x 8) FLASH 14-SOIC",http://ww1.microchip.com/downloads/en/DeviceDoc/50002687A.pdf

README.md

@@ -1,20 +1,61 @@
-# genesis_6button
-Simple PCB + ATTiny404 code for a 6-button mega drive controller.
+# Six button Sega Mega Drive / Genesis controller board
 
-This is a KiCad project for a board and accompanying ATTiny404 code to implement a replacement for the custom chip in the 6-button mega drive/genesis controller.
+This repository contains a KiCad project for a six button Sega Mega Drive / Genesis controller board as well as ATTiny404 micro controller code to implement a replacement for the 6 button Sega Mega Drive controller's custom chip. This board is also compatible with the ZX Spectrum Next and its clones.
 
 **Note: the `main` HEAD is not necessarily tested! Tested revisions of the board+firmware will be tagged**
 
-Latest tested fab here: https://oshpark.com/shared_projects/aK2wBkfg
+## How do I program the controller?
 
-Currently there is a 14-pin dual row header used for the buttons because I was unaware of the brook 20 pin header at the time. I might add that pinout to future boards.
+**DISCLAIMER: This project is provided "as is" for educational purposes only. The authors shall not be held liable for any damage to equipment, data loss, or personal injury incurred through the assembly or use of this project. Proceed at your own risk.**
+
+The ATtiny404 uses UPDI (Unified Program and Debug Interface) for programming, not ISP like older AVR MCUs. 
+
+There are several ways to program the ATtiny404 but probably the most affordable way is to use **avrdude** with a USB serial adapter. serialupdi mode has been supported by **avrdude** since v7.
+
+You will need the following:
+
+* A USB serial adapter such as the [FTDI FT232](https://www.amazon.co.uk/dp/B07BBPX8B8)
+* A 4.7 KOhm resistor. A resistor in the range of 3.3K to 10KOhm should be fine if you don't have a 4.7KOhm resistor.
+* 5x female to female jumper (DuPont) wires.
+
+The +5V and GND headers are wired directly from the serial adapter to the UPDI header. You must create a "Y" jumper cable that connects both the RX and TX pins on your serial adapter to the single UPDI pin on the controller PCB.
+
+The UPDI pin is the bottom left UPDI header pin that has the square footprint in this schematic screenshot. The resistor needs to be connected to the TX wire of your Y cable. Ensure that your serial adapter voltage selection header is set to 5V.
+
+![UPDI header schematic](images/UPDI-header-pinout.png)
+
+![USB serial to UPDI header wiring](images/UPDI-wiring.jpg)
+
+You should only need to have the ATtiny and the UPDI header soldered to the PCB to program it.
+
+Once you have the board connected as shown above, you can program the firmware under Linux using:
+
+```
+avrdude  -p t404 -c serialupdi -P /dev/ttyUSB0 -U flash:w:main.hex
+```
+
+Or under Windows:
 
 ```
-     C  1 | 2  Z
-     B  3 | 4  Y
-     A  5 | 6  X
-  LEFT  7 | 8 GND
- RIGHT  9 | 10 GND
-  DOWN 11 | 12 MODE
-    UP 13 | 14 START
+avrdude.exe -p t404 -c serialupdi -P COM6 -U flash:w:main.hex
 ```
+
+Make sure you set the serial port device correctly by checking **dmesg** output under Linux or **Device Manager** under Windows.
+
+## Building a joystick
+
+The cable is connected to the J2 header using this pinout:
+
+![Mega Drive controller cable pinout](images/Mega-Drive-connector-pinout.jpg)
+
+Pin 1 on J2 and all of the chips is marked on the PCB silkscreen with a small white dot to the side of pin 1.
+
+Here's photo of this board wired up to a Sanwa clone joystick and housed within a 3D printed [Uzebox fightstick](https://uzebox.org/wiki/Joystick) case:
+
+![Sanwa joystick in Uzebox fightstick case](images/Wired--MD-controller.jpg)
+
+## Credits
+
+Schematic and ATtiny code by [R.F.Merrill](https://github.com/rfmerrill)
+
+Silkscreen and documentation by [Dan MacDonald](https://github.com/danboid/)

atmel_studio/genesis_6button/build.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+# This is a script to build the 6 button Mega Drive controller PCB firmware.
+# You need avr-gcc version 8 or later and avr-libc installed to build this code.
+
+# Exit on error, unset variables, catch errors behind a pipe
+set -euo pipefail
+
+# Move to the directory where the script is located
+cd "$(dirname "$0")"
+
+# Remove previous build, if it exists.
+rm -f main.elf main.hex
+
+# Build controller firmware.
+avr-gcc -mmcu=attiny404 -O3 -Wall -Wextra main.c -o main.elf
+avr-objcopy -O ihex -R .eeprom main.elf main.hex

atmel_studio/genesis_6button/main.hex

@@ -0,0 +1,31 @@
+:1000000019C028C027C026C025C024C023C022C0D4
+:1000100021C020C020C01EC01DC01CC01BC01AC0F3
+:1000200019C018C017C016C015C014C013C012C024
+:1000300011C010C011241FBECFEFCDBFDFE3DEBF64
+:100040002FE3A0E0BFE301C01D92A130B207E1F7AA
+:1000500015D0C4C0D5CF8F931F9280E0182E80E1B9
+:1000600080930B0A1092000A81E08093003F109267
+:1000700020040C980F981F908F91189588ED84BFDD
+:1000800081E08093610080E98093000480911504F1
+:10009000886080931504F894109220040C980F98AF
+:1000A000109224047894000000000000000000007A
+:1000B0000000000000000000000000000000000040
+:1000C0000000000000000000000000000000000030
+:1000D0000000000000008091080485FFFFCF80E150
+:1000E00040E25EE421E03FE0F894109220040C9896
+:1000F0000F98109224047894000000000000000083
+:10010000000000001199FECF000000000000000078
+:1001100000000000119BFECF1092003F1092000AD9
+:100120001092200A1092210A8093010A4093280A13
+:100130005093290A80930A0A2093000A00000000C5
+:1001400000000000000000001199FECF9091003FD8
+:100150009111CACF00000000000000000000000064
+:10016000119BFECF9091003F9111BECF0000000087
+:1001700000000000000000001199FECFF8940F9AD3
+:10018000309320040C9A78949091003F9111ACCF59
+:10019000000000000000000000000000119BFECFE6
+:1001A000F894109220040F9830932404789490913E
+:1001B000003F911199CF00000000000000000000F6
+:1001C00000001199FECFF8940F9A309320040C98F8
+:1001D00078949091003F9115E1F386CFF894FFCF8A
+:00000001FF

kicad/genesis_6button/genesis_6button-cache.lib

@@ -144,23 +144,6 @@ X Pin_9 9 -200 -100 150 R 50 50 1 1 P
 ENDDRAW
 ENDDEF
 #
-# Connector_TestPoint
-#
-DEF Connector_TestPoint TP 0 30 N N 1 F N
-F0 "TP" 0 270 50 H V C CNN
-F1 "Connector_TestPoint" 0 200 50 H V C CNN
-F2 "" 200 0 50 H I C CNN
-F3 "" 200 0 50 H I C CNN
-$FPLIST
- Pin*
- Test*
-$ENDFPLIST
-DRAW
-C 0 130 30 0 1 0 N
-X 1 1 0 0 100 U 50 50 1 1 P
-ENDDRAW
-ENDDEF
-#
 # Device_C
 #
 DEF Device_C C 0 10 N Y 1 F N
@@ -179,26 +162,6 @@ X ~ 2 0 -150 110 U 50 50 1 1 P
 ENDDRAW
 ENDDEF
 #
-# Device_CP
-#
-DEF Device_CP C 0 10 N Y 1 F N
-F0 "C" 25 100 50 H V L CNN
-F1 "Device_CP" 25 -100 50 H V L CNN
-F2 "" 38 -150 50 H I C CNN
-F3 "" 0 0 50 H I C CNN
-$FPLIST
- CP_*
-$ENDFPLIST
-DRAW
-S -90 20 90 40 0 1 0 N
-S 90 -20 -90 -40 0 1 0 F
-P 2 0 1 0 -70 90 -30 90 N
-P 2 0 1 0 -50 110 -50 70 N
-X ~ 1 0 150 110 D 50 50 1 1 P
-X ~ 2 0 -150 110 U 50 50 1 1 P
-ENDDRAW
-ENDDEF
-#
 # Device_R
 #
 DEF Device_R R 0 0 N Y 1 F N
@@ -246,21 +209,6 @@ X PB0 9 -600 400 100 R 50 50 1 1 T
 ENDDRAW
 ENDDEF
 #
-# Mechanical_MountingHole
-#
-DEF Mechanical_MountingHole H 0 40 Y Y 1 F N
-F0 "H" 0 200 50 H V C CNN
-F1 "Mechanical_MountingHole" 0 125 50 H V C CNN
-F2 "" 0 0 50 H I C CNN
-F3 "" 0 0 50 H I C CNN
-$FPLIST
- MountingHole*
-$ENDFPLIST
-DRAW
-C 0 0 50 0 1 50 N
-ENDDRAW
-ENDDEF
-#
 # power_+5V
 #
 DEF power_+5V #PWR 0 0 Y Y 1 F P