From f2be4e3b459f757cd791cced1c33cccb1c4a0113 Mon Sep 17 00:00:00 2001
From: Clyne Sullivan <clyne@bitgloo.com>
Date: Sat, 15 Apr 2023 12:50:32 -0400
Subject: [PATCH] run at 48mhz

---
 02-dac/main.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/02-dac/main.c b/02-dac/main.c
index 4c38595..3fc7df7 100644
--- a/02-dac/main.c
+++ b/02-dac/main.c
@@ -7,6 +7,11 @@ unsigned int adc_read(void);
 
 int main(void)
 {
+    while ((RCC->CR & 0x00000002) == 0) {;} // wait till MSI is ready
+    FLASH->ACR |= 2; // Add two wait-states for 48MHz operation
+    RCC->CR = (RCC->CR & ~0x000000F0) | 0x000000B0 | RCC_CR_MSIRGSEL; // Switch to 48 MHz clock
+    while ((RCC->CR & 0x00000002) == 0) {;} // wait till MSI is ready
+
     adc_init();
 
     // DAC initialization:
@@ -29,7 +34,7 @@ int main(void)
         yprev = y;
 
         // Add some delay between samples
-        for (int i = 0; i < 100; ++i);
+        //for (int i = 0; i < 100; ++i);
     }
 }