Added details on RTC oscillator startup delay and implemented a delay_us function. Added information about NO_INLINE and USE_SLOW_SHOW to example user_settings.h. Moved the USE_SLOW_SHA2 into the SHA512 area.

IDE/ROWLEY-CROSSWORKS-ARM/hw.h

@@ -15,6 +15,9 @@ void hw_uart_printchar(int c);
 void hw_watchdog_disable(void);
 uint32_t hw_rand(void);
 
+// Delay functions
+void delay_us(uint32_t microseconds);
+
 
 #endif /* WOLFSSL_ROWLEY_HW_H */
 

IDE/ROWLEY-CROSSWORKS-ARM/kinetis_hw.c

@@ -58,6 +58,16 @@
 /***********************************************/
 
 // Private functions
+static uint32_t mDelayCyclesPerUs = 0;
+#define NOP_FOR_LOOP_INSTRUCTION_COUNT  6
+static void delay_nop(uint32_t count)
+{
+   int i;
+   for(i=0; i<count; i++) {
+      __asm volatile("nop");
+   }
+}
+
 static void hw_mcg_init(void)
 {
     /* Adjust clock dividers (core/system=div/1, bus=div/2, flex bus=div/2, flash=div/4) */
@@ -119,6 +129,9 @@ static void hw_uart_init(void)
 
 static void hw_rtc_init(void)
 {
+    /* Init nop delay */
+    mDelayCyclesPerUs = (SYS_CLK_KHZ / 1000 / NOP_FOR_LOOP_INSTRUCTION_COUNT);
+
     /* Enable RTC clock and oscillator */
     SIM->SCGC6 |= SIM_SCGC6_RTC_MASK;
 
@@ -141,10 +154,8 @@ static void hw_rtc_init(void)
         /* Turn on */
         RTC->CR |= RTC_CR_OSCE_MASK;
 
-        /* Wait RTC startup delay */
+        /* Wait RTC startup delay 1000 us */
-        for (i=0; i<10000; i++) {
+        delay_us(1000);
-            asm("nop");
-        }
     }
 
     /* Enable counter */
@@ -203,6 +214,12 @@ uint32_t hw_rand(void)
     return RNG->OR; /* Return next value in FIFO output register */
 }
 
+void delay_us(uint32_t microseconds)
+{
+   delay_nop(mDelayCyclesPerUs * microseconds);
+}
+
+
 // Watchdog
 void hw_watchdog_disable(void)
 {

IDE/ROWLEY-CROSSWORKS-ARM/user_settings.h

@@ -156,6 +156,8 @@ extern "C" {
 /* Sha */
 #undef NO_SHA
 #if 1
+    /* 1k smaller, but 25% slower */
+    //#define USE_SLOW_SHA
 #else
     #define NO_SHA
 #endif
@@ -163,8 +165,6 @@ extern "C" {
 /* Sha256 */
 #undef NO_SHA256
 #if 1
-    /* over twice as small, but 50% slower */
-    //#define USE_SLOW_SHA2
 #else
     #define NO_SHA256
 #endif
@@ -179,6 +179,9 @@ extern "C" {
     #if 1
         #define WOLFSSL_SHA384
     #endif
+
+    /* over twice as small, but 50% slower */
+    //#define USE_SLOW_SHA2
 #endif
 
 /* MD5 */
@@ -306,6 +309,12 @@ extern "C" {
 #undef  NO_CRYPT_BENCHMARK
 //#define NO_CRYPT_BENCHMARK
 
+/* In-lining of misc.c functions */
+/* If defined, must include wolfcrypt/src/misc.c in build */
+/* Slower, but about 1k smaller */
+#undef  NO_INLINE
+//#define NO_INLINE
+
 #undef  NO_FILESYSTEM
 #define NO_FILESYSTEM