From 8d9cca1503d3a6c35631274579051b2b29124d67 Mon Sep 17 00:00:00 2001
From: KLASSENTS <klassen@elron.tech>
Date: Fri, 30 May 2025 11:44:46 +0700
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---
 cores/arduino/board.cpp | 40 +++++++++++++++++++++++++++++-----------
 1 file changed, 29 insertions(+), 11 deletions(-)

diff --git a/cores/arduino/board.cpp b/cores/arduino/board.cpp
index bd7fb97..ed7cb89 100644
--- a/cores/arduino/board.cpp
+++ b/cores/arduino/board.cpp
@@ -3,23 +3,39 @@
 #include "mik32_hal_irq.h"
 #include "Arduino.h"
 
-// --------------------- change flash cache limit --------------------- // 
+// --------------------- flash cache limit --------------------- // 
 #include "mcu32_memory_map.h"
 #include "mik32_hal_spifi_w25.h"
-#define CLIMIT_NEW  (2 * 256 * 1024)  // Новый предел кэширования
 
-// Объявляем, что эта функция исполняется из RAM
+// define board flash size
+#if defined(ARDUINO_START_MIK32_V1)
+    #define FLASH_SIZE  0x00400000  // 4 Mb
+#elif defined(ARDUINO_ACE_UNO_16MB)
+    #define FLASH_SIZE  0x01000000  // 16 Mb
+#elif defined(ARDUINO_ACE_UNO_32MB)
+    #define FLASH_SIZE  0x02000000  // 32 Mb
+#else
+    #define FLASH_SIZE  0x00800000  // 8 Mb
+#endif
+// define margin from flash end
+#define FLASH_END_OFFSET    0x1000
+
+// values from ld script
+extern uint8_t __TEXT_START__[];
+extern uint8_t __TEXT_END__[];
+
+// RAM-function for updating flash cache limit by app size to improve performance
 __attribute__((section(".ram_text"))) void updateCacheLimit(void)
 {
-    uint32_t MCMDbackup = SPIFI_CONFIG->MCMD;           // Прочитать текущие настройки из регистра MCMD
-    SPIFI_CONFIG->STAT |= SPIFI_CONFIG_STAT_RESET_M;    // Сброс режима MCMD: установить бит RESET
-    SPIFI_CONFIG->CLIMIT = CLIMIT_NEW;                  // Установить новое значение CLIMIT
-    SPIFI_CONFIG->MCMD = MCMDbackup;                    // Вернуть обратно значение в регистр MCMD
-}
+    uint32_t new_limit = (uintptr_t)__TEXT_END__ - (uintptr_t)__TEXT_START__ + 128; // 128 byte for margin
+    // limit cache size by flash size with margin
+    if (new_limit > (FLASH_SIZE - FLASH_END_OFFSET))
+        new_limit = FLASH_SIZE - FLASH_END_OFFSET;
 
-uint32_t getCLimit(void)
-{
-    return SPIFI_CONFIG->CLIMIT;
+    uint32_t MCMDbackup = SPIFI_CONFIG->MCMD;           // save current value from MCMD
+    SPIFI_CONFIG->STAT |= SPIFI_CONFIG_STAT_RESET_M;    // reset MCMD mode for writing new CLIMIT
+    SPIFI_CONFIG->CLIMIT = new_limit;                   // set new CLIMIT
+    SPIFI_CONFIG->MCMD = MCMDbackup;                    // restore MCMD value
 }
 
 // --------------------- init --------------------- // 
@@ -39,6 +55,8 @@ extern "C" void SystemInit(void)
    
     // for delays
     SysTick_Init();   
+    // update flash cache limit by app size
+    updateCacheLimit();
 }
 
 // called after setup()