Change analogWrite to ledcWrite, configuration improvements

src/hash.cpp

@@ -0,0 +1,32 @@
+#include "hash.h"
+#include "mbedtls/md.h" // for SHA256
+
+String get_sha256(String payload) {
+    byte shaResult[32];
+    mbedtls_md_context_t ctx;
+    mbedtls_md_type_t md_type = MBEDTLS_MD_SHA256;
+    mbedtls_md_init(&ctx);
+    mbedtls_md_setup(&ctx, mbedtls_md_info_from_type(md_type), 0);
+    mbedtls_md_starts(&ctx);
+    mbedtls_md_update(&ctx, (const unsigned char *) payload.c_str(), payload.length()); 
+    mbedtls_md_finish(&ctx, shaResult);
+    mbedtls_md_free(&ctx);
+    // convert to hex string
+    char buffer[sizeof(shaResult)*2 + 1];
+    const char hexmap[] = "0123456789abcdef";
+    for (int i = 0; i < sizeof(shaResult); i++) {
+        buffer[i*2] = hexmap[(shaResult[i] >> 4) & 0x0F];
+        buffer[i*2+1] = hexmap[shaResult[i] & 0x0F];
+    }
+    buffer[sizeof(buffer) - 1] = '\0';
+    String hash = String(buffer);
+
+    Serial.print("SHA256 payload: ");
+    Serial.print(payload);
+    Serial.println();
+    Serial.print("SHA256-Hash: ");
+    Serial.print(hash);
+    Serial.println();
+
+    return hash;
+}