Add ADC10 application for sampling analog values.

[goodfet] / firmware / include / adc.h

diff --git a/firmware/include/adc.h b/firmware/include/adc.h
new file mode 100644 (file)
index 0000000..ad06a89
--- /dev/null
+++ b/firmware/include/adc.h
@@ -0,0 +1,71 @@
+/*! \file adc.h
+
+       \author Scott Livingston
+
+       \brief Prototypes for ADC application.  Note that this code was
+              written only with the x2274 chip and GoodFET31 in mind;
+              specifically, pin 5 of the (JTAG) header is sampled.
+              Supporting x2618, x1611/12 and other GoodFET boards remains!
+              For timing considerations, see at least Section 20.2.5
+              "Sample and Conversion Timing" (on page 589?) of msp430x2xx
+              family manual.
+
+       \date September 2010
+*/
+
+
+// Identical to that in command.h, but to avoid cyclic dependencies...
+#define u8 unsigned char
+#define u16 unsigned int
+#define u32 unsigned long
+
+
+//! Initialize ADC10 module (specific to 2xx chip family).
+void init_adc10();
+
+//! Uninit/stop ADC10 module (specific to 2xx chip family).
+void uninit_adc10();
+
+//! Return a single, instantaneous sample.
+u16 sample_adc10();
+
+//! Fill cmddata string; sampling repeatedly at a fixed rate.
+u16 nsamples_adc10( u8 N_count, //! Number samples to obtain (bounded w.r.t. cmddata)
+                                                                               u8 t_sample, /*! sample-and-hold time; this is
+                                                                                                                                    written directly to ADC10SHTx
+                                                                                                                                                field of ADC10CTL0 register;
+                                                                                                                                                possible values are
+                                                                                                                                                00   4 ADC10CLK ticks,
+                                                                                                                                                01   8 ADC10CLK ticks,
+                                                                                                                                                10  16 ADC10CLK ticks,
+                                                                                                                                                11  64 ADC10CLK ticks. */
+                                                                               u8 clock_div ); /*! Value by which to divide SMCLK
+                                                                                                                                                         (which is assumed to be 16
+                                                                                                                                                         MHz), then giving
+                                                                                                                                                         ADC10CLK.
+                                                                                                                                                               Possible values are 1..8
+                                                                                                                                                               Cf. Fig. 20-1 (on page 585?)
+                                                                                                                                                         of the msp430x2xxx family
+                                                                                                                                                         manual. */
+
+
+//! Command codes
+#define ADC10_INIT    0x81 //! Initialize ADC10 module (i.e., get ready for sampling).
+#define ADC10_UNINIT  0x82 //! Uninitialize (or "stop") ADC10.
+#define ADC10_1SAMPLE 0x83 //! Capture a single sample.
+
+/*! Capture a sequence of samples at a constant rate and write result
+    till requested number of samples is acquired or cmddata array is
+    filled, whichever is smaller. Hence, in the maximum length case,
+    (CMDDATALEN-4)/2 10-bit samples are obtained (128 total using
+    x2274 chip).
+
+    The command has several possible formats, switched according to
+    the length of received command data (from client). See above
+    comments about nsamples_adc10 function for meaning of ``t_samlpe''
+    and ``clock_div.''
+    
+    length 0  =>  max sample sequence length, t_sample = 3, clock_div = 8;
+           1  =>  user-specified sequence length, t_sample = 3, clock_div = 8;
+           3  =>  user-specified length, t_sample and clock_div. */
+#define ADC10_NSAMPLE 0x84