From 2b3825f38d99d704eb2c186c74af580f75b559d8 Mon Sep 17 00:00:00 2001
From: hkz <tabaglio@posteo.net>
Date: Sat, 12 Jul 2025 18:09:49 +0200
Subject: [PATCH] Update README

---
 README.md | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/README.md b/README.md
index 7ee9a9a..92ab6b8 100644
--- a/README.md
+++ b/README.md
@@ -7,6 +7,21 @@ I decided to reverse engineer it just for fun, and maybe to build a better varia
 
 ![Screenshot of the traced PCB](pics/traced_board.jpg)
 
+## Hardware
+
+### Memory map and protocol
+
+Information on the protocol can be found [here](https://psx-spx.consoledev.net/cheatdevices/#cheat-devices-datel-io), but here is the basic memory map of this device:
+
+```
+  1F000000h-1F01FFFFh R/W Flash (first 128K)
+  1F020010h           R   Comms Link STB pin state (bit0)
+  1F020018h           R   Switch Setting (bit0: 0=Off, 1=On)
+  1F040000h-1F05FFFFh R/W Flash (second 128K)
+  1F060000h           R   Comms Link data in (byte)
+  1F060008h           W   Comms Link data out (byte, pulses ACK to Comms Link)
+```
+
 ## Notes
 
 The PCB was fully disassembled, scanned, and traced to reconstruct the schematic.