diff --git a/libraries/Desktop/support/digital.c b/libraries/Desktop/support/digital.c
new file mode 100644
index 0000000000..691c887999
--- /dev/null
+++ b/libraries/Desktop/support/digital.c
@@ -0,0 +1,22 @@
+// support for digitalRead() and digitalWrite()
+#include <stdio.h>
+#include <stdbool.h>
+#include <time.h>
+#include <sys/time.h>
+#include <stdint.h>
+#include "desktop.h"
+
+
+int digitalRead(uint8_t address)
+{
+	switch (address) {
+	case 40:
+		// CLI slider switch
+		return desktop_state.slider?0:1;
+
+	default:
+		break;
+	}
+	printf("digitalRead(0x%x) unsupported\n", address);
+	return 0;
+}