stm32: Use 12Mhz nominal internal clock in stm32f0_i2c.c

Increase the internal nominal clock from 8Mhz to 12Mhz - this improves
support for higher chip frequencies.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

1 files changed, 9 insertions, 9 deletions

diff --git a/src/stm32/stm32f0_i2c.c b/src/stm32/stm32f0_i2c.c
index ef12145f..9f4bbcc6 100644
--- a/src/stm32/stm32f0_i2c.c
+++ b/src/stm32/stm32f0_i2c.c
@@ -149,17 +149,17 @@ i2c_setup(uint32_t bus, uint32_t rate, uint8_t addr)
         gpio_peripheral(ii->sda_pin, ii->function | GPIO_OPEN_DRAIN, 1);
 
         // Set 100Khz frequency and enable
-        uint32_t nom_i2c_clock = 8000000;  // 8mhz internal clock = 125ns ticks
-        uint32_t scll = 40; // 40 * 125ns = 5us
-        uint32_t sclh = 32; // 32 * 125ns = 4us
-        uint32_t sdadel = 4; // 4 * 125ns = 500ns
-        uint32_t scldel = 10; // 10 * 125ns = 1250ns
+        uint32_t nom_i2c_clock = 12000000; // 12mhz internal clock (83.3ns tick)
+        uint32_t scll = 60; // 60 * 83.3ns = 5us
+        uint32_t sclh = 48; // 48 * 83.3ns = 4us
+        uint32_t sdadel = 6; // 6 * 83.3ns = 500ns
+        uint32_t scldel = 15; // 15 * 83.3ns = 1250ns
         // Clamp the rate to 400Khz
         if (rate >= 400000) {
-            scll = 10; // 10 * 125ns = 1250ns
-            sclh = 4; // 4 * 125 = 500ns
-            sdadel = 3; // 3 * 125 = 375ns
-            scldel = 4; // 4 * 125 = 500ns
+            scll = 15; // 15 * 83.3ns = 1250ns
+            sclh = 6; // 6 * 83.3 = 500ns
+            sdadel = 4; // 4 * 83.3 = 333ns
+            scldel = 6; // 6 * 83.3 = 500ns
         }
 
         uint32_t pclk = get_pclock_frequency((uint32_t)i2c);