From f8081eeb04c9cb511adaf58e201c7cfbe1ddfbd4 Mon Sep 17 00:00:00 2001
From: Marti Bolivar <mbolivar@leaflabs.com>
Date: Fri, 25 Mar 2011 20:09:30 -0400
Subject: Final stm32_pin_info design candidate; ADC3 support on Native.

Added an adc_dev to struct stm32_pin_info.  This was necessary to add
support for the channels on the Native which are only connected to
ADC3, but it does add a bunch of NULLs to the PIN_MAPs.

I don't think any other peripherals need representation on a per-pin
basis.  Each peripheral library will be responsible for keeping track
of related GPIO ports and bits, and we can throw #defines in to
boards/*.h for other things (e.g. BOARD_SPI1_MISO_PIN).

Fleshed out the ADC refactor and brought it more in keeping with the
new design as it evolves.

A couple of other tweaks.  Notably: waitForButtonPress() now takes a
default argument meaning "wait forever".

Removed Maple-specific documentation from core functions in io.h; this
information will need to go into the individual board docs files.
---
 libmaple/adc.c | 65 ++++++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 43 insertions(+), 22 deletions(-)

(limited to 'libmaple/adc.c')

diff --git a/libmaple/adc.c b/libmaple/adc.c
index 3d38596..73dce0a 100644
--- a/libmaple/adc.c
+++ b/libmaple/adc.c
@@ -59,43 +59,44 @@ adc_dev adc3 = {
 const adc_dev *ADC3 = &adc3;
 #endif
 
-static void adc_calibrate(const adc_dev *dev);
-
 /**
- * @brief Initialize an ADC peripheral. Only supports software triggered
- * conversions.
+ * @brief Initialize an ADC peripheral.
+ *
+ * Initializes the RCC clock line for the given peripheral, using ADC
+ * prescaler RCC_ADCPRE_PCLK_DIV_6.  Resets ADC device registers.
+ *
  * @param dev ADC peripheral to initialize
- * @param flags unused
  */
-void adc_init(const adc_dev *dev, uint32 flags) {
-    /* Spin up the clocks */
+void adc_init(const adc_dev *dev) {
     rcc_set_prescaler(RCC_PRESCALER_ADC, RCC_ADCPRE_PCLK_DIV_6);
     rcc_clk_enable(dev->clk_id);
     rcc_reset_dev(dev->clk_id);
-
-    /* Software triggers conversions, conversion on external events */
-    adc_set_extsel(dev, 7);
-    adc_set_exttrig(dev, 1);
-
-    /* Enable the ADC */
-    adc_enable(dev);
-
-    /* Calibrate ADC */
-    adc_calibrate(dev);
 }
 
 /**
  * @brief Set external event select for regular group
- * @param dev adc device
- * @param trigger event to select. See ADC_CR2 EXTSEL[2:0] bits.
+ * @param dev ADC device
+ * @param event Event used to trigger the start of conversion.
+ * @see adc_extsel_event
  */
-void adc_set_extsel(const adc_dev *dev, uint8 trigger) {
+void adc_set_extsel(const adc_dev *dev, adc_extsel_event event) {
     uint32 cr2 = dev->regs->CR2;
     cr2 &= ~ADC_CR2_EXTSEL;
-    cr2 |= (trigger & 0x7) << 17;
+    cr2 |= event;
     dev->regs->CR2 = cr2;
 }
 
+/**
+ * @brief Call a function on all ADC devices.
+ * @param fn Function to call on each ADC device.
+ */
+void adc_foreach(void (*fn)(const adc_dev*)) {
+    fn(ADC1);
+    fn(ADC2);
+#ifdef STM32_HIGH_DENSITY
+    fn(ADC3);
+#endif
+}
 
 /**
  * @brief Turn the given sample rate into values for ADC_SMPRx. Don't
@@ -125,7 +126,7 @@ void adc_set_sample_rate(const adc_dev *dev, adc_smp_rate smp_rate) {
  * @brief Calibrate an ADC peripheral
  * @param dev adc device
  */
-static void adc_calibrate(const adc_dev *dev) {
+void adc_calibrate(const adc_dev *dev) {
     __io uint32 *rstcal_bit = bb_perip(&(dev->regs->CR2), 3);
     __io uint32 *cal_bit = bb_perip(&(dev->regs->CR2), 2);
 
@@ -137,3 +138,23 @@ static void adc_calibrate(const adc_dev *dev) {
     while (*cal_bit)
         ;
 }
+
+/**
+ * @brief Perform a single synchronous software triggered conversion on a
+ * channel.
+ * @param dev ADC device to use for reading.
+ * @param channel channel to convert
+ * @return conversion result
+ */
+uint16 adc_read(const adc_dev *dev, uint8 channel) {
+    adc_reg_map *regs = dev->regs;
+
+    adc_set_reg_seqlen(dev, 1);
+
+    regs->SQR3 = channel;
+    regs->CR2 |= ADC_CR2_SWSTART;
+    while(!(regs->SR & ADC_SR_EOC))
+        ;
+
+    return (uint16)(regs->DR & ADC_DR_DATA);
+}
-- 
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