UA1ZBE Custom Firmware v1.0

Features:
- VFO mode with direct frequency input
- POCSAG decoder (512/1200 baud) with BCH(31,21) correction
- Full-screen Spectrum analyzer
- FM Radio receiver
- RSSI signal indicator overlay
- Custom boot splash (UA1ZBE / POCSAG pager / build date)

Architecture:
- app/mode.c — mode dispatcher (VFO/POCSAG/Spectrum/FM)
- app/boot_splash.c — 2-second boot splash
- app/pocsag/ — POCSAG decoder + BCH correction
- app/display_rssi.c — RSSI indicator
- main.c — entry point with custom init
- syscalls.c — bare-metal _sbrk stub

Build: arm-none-eabi-gcc -Os -flto -Wall -Werror -Wextra
Size: 57.9KB Flash / 3.6KB RAM

Controls:
- 0-9: Direct frequency input (VFO)
- SK2: POCSAG mode
- SK1: Spectrum analyzer
- 0: FM Radio
- EXIT: Return to VFO
- F/*: Toggle 512/1200 baud (in POCSAG)

external/CMSIS_5/CMSIS/RTOS2/RTX/Source/rtx_delay.c

@@ -0,0 +1,111 @@
+/*
+ * Copyright (c) 2013-2021 Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the License); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an AS IS BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * -----------------------------------------------------------------------------
+ *
+ * Project:     CMSIS-RTOS RTX
+ * Title:       Delay functions
+ *
+ * -----------------------------------------------------------------------------
+ */
+
+#include "rtx_lib.h"
+
+
+//  ==== Service Calls ====
+
+/// Wait for Timeout (Time Delay).
+/// \note API identical to osDelay
+static osStatus_t svcRtxDelay (uint32_t ticks) {
+  osStatus_t status;
+
+  if (ticks == 0U) {
+    EvrRtxDelayError((int32_t)osErrorParameter);
+    //lint -e{904} "Return statement before end of function" [MISRA Note 1]
+    return osErrorParameter;
+  }
+
+  if (osRtxThreadWaitEnter(osRtxThreadWaitingDelay, ticks)) {
+    EvrRtxDelayStarted(ticks);
+    status = osOK;
+  } else {
+    EvrRtxDelayError((int32_t)osError);
+    status = osError;
+  }
+
+  return status;
+}
+
+/// Wait until specified time.
+/// \note API identical to osDelayUntil
+static osStatus_t svcRtxDelayUntil (uint32_t ticks) {
+  osStatus_t status;
+
+  ticks -= osRtxInfo.kernel.tick;
+  if ((ticks == 0U) || (ticks > 0x7FFFFFFFU)) {
+    EvrRtxDelayError((int32_t)osErrorParameter);
+    //lint -e{904} "Return statement before end of function" [MISRA Note 1]
+    return osErrorParameter;
+  }
+
+  if (osRtxThreadWaitEnter(osRtxThreadWaitingDelay, ticks)) {
+    EvrRtxDelayUntilStarted(ticks);
+    status = osOK;
+  } else {
+    EvrRtxDelayError((int32_t)osError);
+    status = osError;
+  }
+
+  return status;
+}
+
+//  Service Calls definitions
+//lint ++flb "Library Begin" [MISRA Note 11]
+SVC0_1(Delay,      osStatus_t, uint32_t)
+SVC0_1(DelayUntil, osStatus_t, uint32_t)
+//lint --flb "Library End"
+
+
+//  ==== Public API ====
+
+/// Wait for Timeout (Time Delay).
+osStatus_t osDelay (uint32_t ticks) {
+  osStatus_t status;
+
+  EvrRtxDelay(ticks);
+  if (IsException() || IsIrqMasked()) {
+    EvrRtxDelayError((int32_t)osErrorISR);
+    status = osErrorISR;
+  } else {
+    status = __svcDelay(ticks);
+  }
+  return status;
+}
+
+/// Wait until specified time.
+osStatus_t osDelayUntil (uint32_t ticks) {
+  osStatus_t status;
+
+  EvrRtxDelayUntil(ticks);
+  if (IsException() || IsIrqMasked()) {
+    EvrRtxDelayError((int32_t)osErrorISR);
+    status = osErrorISR;
+  } else {
+    status = __svcDelayUntil(ticks);
+  }
+  return status;
+}