add changes for nRF52840-DK

README.md

@@ -45,15 +45,18 @@ to use:
     ./run_example.sh blink
     ```
 
-    This should work if you are using the nRF52-DK platform. For other platforms,
-    you will end up with a TAB file in `target/tab` that you can program onto your
-    Tock board (e.g. with `tockloader install target/tab/blink.tab`).
+    Due to bug #28 this will currently only work if you are using the nRF52-DK platform.
+
+    If you have a nRF52840-DK you must change `link-arg=-Tnrf52_layout.ld` in
+    `.cargo/config` to `link-arg=-Tnrf52840_layout.ld`
 
     If you have a hail board you can flash your device as follows:
      - set the environment variable `hail` to `1`
-     - set  `link-arg=-Tnrf52_layout.ld` in `.cargo/config` to `link-arg=-Thail_layout.ld`
+     - change `link-arg=-Tnrf52_layout.ld` in `.cargo/config` to `link-arg=-Thail_layout.ld`
      - run `run_example.sh` as above.
 
+    For other platforms, you may have to create your own memory layout definition.
+
 ## Using libtock-rs
 
 The easiest way to start using libtock-rs is adding an example to the examples folder.

nrf52840_layout.ld

@@ -0,0 +1,17 @@
+/* Layout for the nRF52840-DK, usable by the examples in this repository. */
+
+MEMORY {
+  /* The application region is 64 bytes (0x40) */
+  FLASH (rx) : ORIGIN = 0x00030040, LENGTH = 0x0005FFC0
+  SRAM (rwx) : ORIGIN = 0x20004000, LENGTH = 62K
+}
+
+/*
+ * Any change to STACK_SIZE should be accompanied by a corresponding change to
+ * `elf2tab`'s `--stack` option
+ */
+STACK_SIZE = 2048;
+
+MPU_MIN_ALIGN = 8K;
+
+INCLUDE layout.ld