added scratch buffer section

README.md

@@ -591,6 +591,20 @@ Eclipse indexer.
 
 # Q7S Utilities and Troubleshooting
 
+## Core commands
+
+Display currently running image:
+
+```sh
+xsc_boot_copy
+```
+
+Rebooting currently running image:
+
+```sh
+xsc_boot_copy -r
+```
+
 ## pa3tool Host Tool
 
 The `pa3tool` is a host tool to interface with the ProASIC3 on the Q7S board. It was
@@ -612,6 +626,40 @@ cat /tmp/test.txt
 
 For more useful combinations, see this [link](https://www.freecodecamp.org/news/the-cat-command-in-linux-how-to-create-a-text-file-with-cat-or-touch/).
 
+## Using the scratch buffer of the ProASIC3
+
+The ProASIC3 has a 1024 byte scratch buffer. The values in this scratch buffer will survive
+a reboot, so this buffer can be used as an alternative to the SD cards to exchange information
+between images or to store mission critical information.
+
+You can use `xsc_scratch --help` for more information.
+
+Write to scratch buffer:
+
+```sh
+xsc_scratch write TEST "1"
+```
+
+Read from scratch buffer:
+
+```sh
+xsc_scratch read TEST
+```
+
+Read all keys:
+
+```sh
+xsc_scratch read
+
+```
+
+Get fill count:
+
+```sh
+xsc_scratch read | wc -c
+```
+
+
 ## Using `system` when debugging
 
 Please note that when using a `system` call in C++/C code and debugging, a new thread will be
@@ -695,20 +743,6 @@ Reading data from CAN:
 candump can0
 ````
 
-## Useful Q7S Linux Commands
-
-Display currently running image:
-
-```sh
-xsc_boot_copy
-```
-
-Rebooting currently running image:
-
-```sh
-xsc_boot_copy -r
-```
-
 ## Preparation of a fresh rootfs and SD card
 
 This section summarizes important changes between a fresh rootfs and the current