feat: Add epicardium stub

Signed-off-by: Rahix <rahix@rahix.de>

epicardium/main.c

+#include "card10.h"
+
+int main(void)
+{
+	card10_init();
+	card10_diag();
+}

epicardium/meson.build

+name = 'epicardium'
+
+elf = executable(
+  name + '.elf',
+  'main.c',
+  dependencies: [libcard10, max32665_startup_core0],
+  link_whole: [max32665_startup_core0_lib, board_card10_lib],
+  link_args: [
+    '-Wl,-Map=' + meson.current_build_dir() + '/' + name + '.map',
+  ],
+)
+
+custom_target(
+  name + '.bin',
+  build_by_default: true,
+  output: name + '.bin',
+  input: elf,
+  command: [build_image, '@INPUT@', '@OUTPUT0@'],
+)

meson.build

@@ -32,4 +32,6 @@ python3 = 'python3'
 
 subdir('lib/')
 subdir('bootloader/')
+
+subdir('epicardium/')
 subdir('hw-tests/')