diff --git a/README.md b/README.md
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+# raspi demo for oled ssd1306 display
+
+## Quick start
+
+> nix-shell
+>
+> rustup target add arm-unknown-linux-musleabihf
+>
+> cargo build --release --target arm-unknown-linux-musleabihf
+
+Then scp the release file to your raspi.
+
+## Example
+
+![picture](./images/01.jpg)
+
+![primitive](./images/02.jpg)
diff --git a/shell.nix b/shell.nix
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+with (import <nixpkgs> {});
+mkShell {
+  nativeBuildInputs = [
+    pkgsCross.muslpi.stdenv.cc
+  ];
+  CARGO_TARGET_ARM_UNKNOWN_LINUX_MUSLEABIHF_LINKER = "${pkgsCross.muslpi.stdenv.cc}/bin/armv6l-unknown-linux-musleabihf-ld";
+}