X-Git-Url: https://robinkrens.nl/gitweb/?a=blobdiff_plain;f=lib%2Fregfunc.c;h=2e2468927f4213e352249b39c99c0aeb52aab1d2;hb=fac4700036ceaafe0d4a2b40d4c9f590d3c407b7;hp=f5bc5391583a9aad79663e8569d6c140ba135423;hpb=43b1749173f70bdf67884d920b93f6a5b1f19a1d;p=cortex-from-scratch

diff --git a/lib/regfunc.c b/lib/regfunc.c
index f5bc539..2e24689 100644
--- a/lib/regfunc.c
+++ b/lib/regfunc.c
@@ -17,8 +17,10 @@
 #include <lib/string.h>
 #include <lib/stdio.h>
 
-#include <sys/mmap.h>
+#include <lib/tinyprintf.h>
 
+#include <sys/mmap.h>
+#include <sys/robsys.h>
 
 // register set bit at position
 void rsetbit(volatile uint32_t * reg, short pos) {
@@ -48,38 +50,6 @@ void rwrite(volatile uint32_t * reg, uint32_t val) {
 }
 
 
-/* DEPRECATED write value (uint8_t) to register 
-void regw_u8(volatile uint32_t * reg, uint8_t val, short shift, short flag) {
-
-	switch(flag) {
-		case OWRITE:
-			*reg = (val << shift);
-			break;
-		case SETBIT:
-			*reg = *reg | (val << shift);
-			break;
-		case CLRBIT:
-			*reg = *reg & ~(val << shift);
-			break;
-	}
-} */
-
-/* DEPRECATED write value (uint32_t) to register 
-void regw_u32(volatile uint32_t * reg, uint32_t val, short shift, short flag) {
-
-	switch(flag) {
-		case OWRITE:
-			*reg = (val << shift);
-			break;
-		case SETBIT:
-			*reg = *reg | (val << shift);
-			break;
-		case CLRBIT:
-			*reg = *reg & ~(val << shift);
-			break;
-	}
-} */
-
 /* Deprecated use printf instead
 char hexbuf[8];
 char * regtohex(uint32_t addr) {
@@ -127,3 +97,26 @@ uint32_t hextoreg(char * a) {
 
 }
 
+/* Busy-loop block implementation. Each iteration will take 3 CPU cycles.
+ * Of course, when interrupts are enabled, the exact delay time will be 
+ * uncertain. 
+ *
+ * Example: for a standard STM32x config board (8MHz) the maximum delay is
+ * 0xFFFF * (1/8,000,000) * 3 = 24.58ms 
+ * */
+static void __block(uint16_t count) {
+
+	asm volatile("b1: subs %0, %1, #1" "\n\t"
+		"bne b1" : "=r" (count) : "r" (count));
+}
+
+/* Delay us microsecond
+ * Note: delay includes setup time (about 4 clockcycles), so is quite
+ * inaccurate  */
+void _block(uint16_t us) {
+	
+	uint16_t count = (us/3) * CLKSPEED_MHZ; // x cycles 
+	__block(count);
+
+}
+