Update README and assembly instructions

README.md

@@ -2,6 +2,22 @@
 
 The goal of this project is to make a cheap and easy to build SPI adapter that connects to the parallel port of an Amiga. Furthermore, the performance of the adapter should be as fast as possible.
 
+## Please note: new hardware incompatible version!
+
+What you are looking at is a new version of this design. It is hardware
+incompatible with the original version. Updating the software without making
+the corresponding hardware changes will not work.
+
+Old versions of this design are available as tags/releases.
+
+### Changes with latest version
+
+Support has been added that allows the SPI device to interrupt the Amiga via the adapter.
+The SD card example driver has been modified to use this interrupt so that the SD card
+can be inserted/ejected as part of normal operations.
+
+A video demonstrating this can be seen here: https://www.youtube.com/watch?v=zJDtiFQgrn0.
+
 ## What parts make up the project?
 
 - An AVR microcontroller, provided by an Arduino Nano board

hardware/assembly-instructions.md

@@ -1,24 +1,40 @@
 # Assembly instructions
 
-The assembly of the adapter is very simple.
+The assembly of the adapter is quite simple.
 You need a parallel port connector and an Arduino Nano.
 Connect the parallel port to the Nano as follows:
 
-| Par. pin # | Par. pin name | Nano pin # | Nano pin name |
-|-----------:|--------------:|-----------:|--------------:|
-|  2 |   D0 | 26 | A0 |
-|  3 |   D1 | 25 | A1 |
-|  4 |   D2 | 24 | A2 |
-|  5 |   D3 | 23 | A3 |
-|  6 |   D4 | 22 | A4 |
-|  7 |   D5 | 21 | A5 |
-|  8 |   D6 |  9 | D6 |
-|  9 |   D7 | 10 | D7 |
-| 11 | BUSY |  7 | D4 |
-| 12 | POUT |  8 | D5 |
-| 20 |  GND |  4 | GND |
+| Par. pin # | Par. pin | Nano pin | Atmega328P |
+|---:|-----:|----:|----:|
+|  2 |   D0 |  A0 | PC0 |
+|  3 |   D1 |  A1 | PC1 |
+|  4 |   D2 |  A2 | PC2 |
+|  5 |   D3 |  A3 | PC3 |
+|  6 |   D4 |  A4 | PC4 |
+|  7 |   D5 |  A5 | PC5 |
+|  8 |   D6 |  D6 | PD6 |
+|  9 |   D7 |  D7 | PD7 |
+| 10 |  ACK |  D9 | PB1 |
+| 11 | BUSY |  D8 | PB0 |
+| 12 | POUT |  D4 | PD4 |
+| 13 |  SEL |  D2 | PD2 |
+| 18..25 |  GND | GND | GND |
 
-Note that pins D0-D5 are connected to port C on the AVR (pins A0-A5 on the Nano) and pins D6-D7 are connected to port D on the AVR (pins D6-D7 on the Nano).
-This is identical to how the [plipbox](https://github.com/cnvogelg/plipbox) connects the parallel port to the Arduino Nano, so it should be possible to use an existing plipbox PCB for this adapter (although this has not been tested).
+## Connecting SD card module to Nano
 
-If you are connecting an SD card module to the adapter then connect pin 13 on the parallel port connector (SEL) to the chip select (CS) pin on the SD card module, and connect the other SPI pins as you normally would connect an SPI module to the Arduino Nano.
+To use the adapter with the example SD card driver (spisd.device),
+connect the SD card module to the Nano as follows:
+
+| SD card | Nano pin | Atmega328P |
+|-----:|----:|----:|
+|   SS | D10 | PB2 |
+| MOSI | D11 | PB3 |
+| MISO | D12 | PB4 |
+|  SCK | D13 | PB5 |
+|   CD |  D3 | PD3 |
+|  VCC | VCC |     |
+|  GND | GND | GND |
+
+CD = Card Detect. Not all modules has this pin available, but since the Micro SD card connectors typically has this pin it should be possible to solder a wire to the connector.
+
+Note that the SD card module must have voltage level translation between the +5V used by the Amiga and the Nano, and the +3.3V used by the SD card.