Diff: main.cpp

Revision:

1:46c26c1de51f

Parent:

0:177a872748b8

Child:

2:41e59824652f

--- a/main.cpp	Sun Jul 08 16:49:43 2012 +0000
+++ b/main.cpp	Thu Jul 12 07:40:48 2012 +0000
@@ -1,32 +1,143 @@
-#include "mbed.h"
-// Use SPI port to write an 8 bit pattern to MIC5821 open collector driver device.
-// MBED led1 lights if pattern read back from MIC5821 matches pattern written
-// Ordinarily the device would be write-only but loopback may be usefull in testing.
-// Cascade output is NOT tristate. Strobe is NOT a CS/SS signal, needs a pulse.
-//
-// Note that the MIC has a speed limit, 3.3MHz at 5v, mine works OK at 1MHz at 3.3v
-// Also input has CMOS thresholds so it may not recognise MBED logic HI when powered
-// from 5v so power it from Vout.
-//
-// Data is clocked in on rising edges so SPI 0,0 or SPI 1,1. 
-
-SPI spi(p5, p6, p7); // mosi, miso, sclk
-
-DigitalOut strobe(p21);
-DigitalOut led(LED1);
-
-int main() {
-    spi.format(8,0);
-    spi.frequency(1000000);
-    char leds,prev;
-    leds=0;
-    while(1) {
-        prev=spi.write(leds)+1;
-        led=(prev == leds);
-        leds++;
-        strobe=1;
-        wait_us(1);
-        strobe=0;
-        wait(0.5);
-    }
-}
+#include "mbed.h"
+// Use SPI port to control MAX110/111 Analog to digital converter
+// MAX110 is split-supply device, MAX111 single supply.
+// Devices require 5v for full performance, may be testable at 3.3v
+// 
+//
+// Conversion is SLOW. 
+//
+// Data is clocked in on rising edges so SPI 0,0 or SPI 1,1. 
+
+Serial pc(USBTX, USBRX); // tx, rx
+
+SPI spi(p5, p6, p7); // mosi, miso, sclk
+DigitalOut max_cs(p22);
+DigitalIn  max_busy(p23);
+
+//module libmax110
+//
+//const
+#define      max_12bit 0x9200
+#define      max_13bit 0x8600
+#define      max_14bit 0x8c00
+#define      max_div4  0x0100
+#define      max_div2  0x0080
+#define      max_chan1 0x0000
+#define      max_chan2 0x0010
+#define      max_full  0x000c
+//#define      max_gain  0b0000000000001000
+#define      max_ofs   0x0004
+//
+//   procedure max_init(dim mode as word, dim byref port as //byte, dim cs,bf as byte)
+//
+//   mode must be one of max_12bit, max_13bit, max_14bit
+//   mode may be modified by "or-ing" with max_div2 or max_div4 to set clock divider
+//   mode may be modified by "or-ing" with max_chan1 or //max_chan2 to set input channel
+//   mode may be modified by "or-ing" with a calibration type //max_full,max_ofs
+//
+//   port is the port the busy and cs pins are connected to (doesn't have to be PORTC)
+//   cs is the bit number for the chip select pin
+//   bf is the bit number for the busy flag pin
+//
+//   function max_read(dim byref data as integer) as boolean
+//
+// notes returns true if a value was read, immediately restarts converter
+// otherwise returns false
+//
+// result is integer, valid results are from -16384 through 16383.
+// values beyond this are overrange
+//
+//
+// MAX110/111 Control register bits
+// 15         !NOOP   Set to 1 for action, 0 for pass-through
+// 14         NU, set to 0
+// 13         NU, set to 0
+//                             CONV 4,3,2,1
+// 12         CONV4                 1 0 0 1  20ms
+// 11         CONV3                 0 0 1 1  40ms
+// 10         CONV2                 0 1 1 0  160ms
+//  9         CONV1                 0 0 0 0  200ms SPECIAL
+//                    SPECIAL = NO INTERNAL GAIN CALIBRATION, FIX IN SOFTWARE
+//  8         DV4           1=DIVIDE XCLK BY 4
+//  7         DV2           1=DIVIDE XCLK BY 2
+//
+//  6         NU, set to 0
+//  5         NU, set to 0
+
+//  4         CHS               0:CHANNEL 1   1:CHANNEL2
+//
+//                                    CAL NUL FUNCTION
+//                                     1   1   INTERNAL ZERO (PERFORM FIRST)
+//  3         GAIN CAL                 1   0   INTERNAL GAIN (NEXT)
+//  2         OFFSET NUL               0   1   INPUT NUL (LAST)
+//                                     0   0   NORMAL CONVERT
+//  1         PDX POWER DOWN OSC
+//  0         PD POWER DOWN ADC
+//
+//
+unsigned int max_mode; 
+//
+void max_setup(unsigned int mmode)
+{
+  max_mode=mmode;
+      pc.printf("setup %x\n",max_mode);
+  max_cs=0;
+      wait_us(1);
+      spi.write((max_mode & 0xff00) >> 8);
+      spi.write(max_mode & 0xff);
+  max_cs=1;
+}
+
+
+int max_read(int *data)
+{
+  if (max_busy)
+  {
+    if (max_mode & 0x0c)
+    {
+      max_mode = max_mode - 0x04;
+      pc.printf("cal %x\r\n",max_mode);
+      
+      max_cs=0;
+      wait_us(1);
+      spi.write((max_mode & 0xff00) >> 8);
+      spi.write(max_mode & 0xff);
+      max_cs=1;
+      wait(0.1);
+      return(false);
+    }
+    else
+    {
+      short t;
+      max_cs=0;
+      wait_us(1);
+      t    =spi.write((max_mode & 0xff00) >> 8);
+      t    =spi.write(max_mode & 0xff) | (t<<8);
+      *data= (int) t;
+      max_cs=1;
+      return(true);
+    }
+  }
+  else
+  {
+    return(false);
+  }
+}
+
+
+int main() {
+    spi.format(8,0);
+    spi.frequency(100000);
+    pc.printf("Start converter\r\n");
+    max_setup(max_14bit | max_full);
+//    max_busy.mode(PullUp);
+    while(1) {
+      int val;
+      val=0;
+      if (max_read(&val))
+      {
+        pc.printf("Readout: %d \r",val);
+//        wait(1);
+      }
+    }
+}