board: enable TIM2 late

This was triggered by moving log_init and adding i2c_init on top of
the existing ethernet setup/init after the timer setup and enable.
Thanks @cjbe for debugging.

Also move the RCC peripheral enable calls out of i2c and eth setup.

close #55
supersedes #62

src/board.rs

@@ -399,8 +399,7 @@ fn tim2_setup(tim2: &pac::TIM2) {
     tim2.dier.write(|w| w.ude().set_bit());
     tim2.egr.write(|w| w.ug().set_bit());
     tim2.cr1.modify(|_, w|
-        w.dir().clear_bit()  // up
+        w.dir().clear_bit());  // up
-         .cen().set_bit());  // enable
 }
 
 fn dma1_setup(dma1: &pac::DMA1, dmamux1: &pac::DMAMUX1, ma: usize, pa0: usize, pa1: usize) {
@@ -524,9 +523,19 @@ pub fn init() {
 
     tim2_setup(&dp.TIM2);
 
-    let i2c2 = dp.I2C2;
+    rcc.apb1lenr.modify(|_,w| w.i2c2en().set_bit());
-    i2c::setup(&rcc, &i2c2);
+    i2c::setup(&dp.I2C2);
 
-    eth::setup(&rcc, &dp.SYSCFG);
+    rcc.apb4enr.modify(|_, w| w.syscfgen().set_bit());
+    rcc.ahb1enr.modify(|_, w| {
+        w.eth1macen().set_bit()
+         .eth1txen().set_bit()
+         .eth1rxen().set_bit()
+    });
+    dp.SYSCFG.pmcr.modify(|_, w| unsafe { w.epis().bits(0b100) });  // RMII
     eth::setup_pins(&dp.GPIOA, &dp.GPIOB, &dp.GPIOC, &dp.GPIOG);
+
+    // enable TIM2 this must be late to be able to handle the first ADC SPI
+    // interrupt in time
+    dp.TIM2.cr1.modify(|_, w| w.cen().set_bit());
 }

src/eth.rs

@@ -85,19 +85,6 @@ use self::cr_consts::*;
 // 200 MHz AHB clock = eth_hclk
 const CLOCK_RANGE: u8 = ETH_MACMIIAR_CR_HCLK_DIV_102;
 
-
-pub fn setup(rcc: &pac::RCC, syscfg: &pac::SYSCFG) {
-    rcc.apb4enr.modify(|_, w| w.syscfgen().set_bit());
-    rcc.ahb1enr.modify(|_, w| {
-        w.eth1macen().set_bit()
-         .eth1txen().set_bit()
-         .eth1rxen().set_bit()
-    });
-    syscfg.pmcr.modify(|_, w| unsafe { w.epis().bits(0b100) });  // RMII
-    //rcc.ahb1rstr.modify(|_, w| w.eth1macrst().set_bit());
-    //rcc.ahb1rstr.modify(|_, w| w.eth1macrst().clear_bit());
-}
-
 pub fn setup_pins(gpioa: &pac::GPIOA, gpiob: &pac::GPIOB,
                   gpioc: &pac::GPIOC, gpiog: &pac::GPIOG) {
     // PA1 RMII_REF_CLK

src/i2c.rs

@@ -21,11 +21,7 @@ pub enum Error {
 const N_RETRY: usize = 100; // ~ 10ms @ 100 kHz bus clock
 
 
-pub fn setup(rcc: &pac::RCC, i2c: &pac::I2C2) {
+pub fn setup(i2c: &pac::I2C2) {
-    rcc.apb1lenr.modify(|_,w|
-        w.i2c2en().set_bit()
-    );
-
     // Disable the peripheral before setting timings
     i2c.cr1.modify(|_, w| w.pe().clear_bit());