More pretty graphs, and initial correction calculation

firmware/main.c

@@ -77,20 +77,20 @@ uint32_t sys_time_seconds = 0;
  */
 static uint16_t timer_period_lookup[NBITS] = {
     /* LSB here */
-    A - C + (B<< 0),
-    A - C + (B<< 1),
-    A - C + (B<< 2),
-    A - C + (B<< 3),
-    A - C + (B<< 4),
-    A - C + (B<< 5),
-    A - C + (B<< 6),
-    A - C + (B<< 7),
-    A - C + (B<< 8),
-    A - C + (B<< 9),
-    A - C + (B<<10),
-    A - C + (B<<11),
-    A - C + (B<<12),
-    A - C + (B<<13),
+    A + (B<< 0) - C,
+    A + (B<< 1) - C,
+    A + (B<< 2) - C,
+    A + (B<< 3) - C,
+    A + (B<< 4) - C,
+    A + (B<< 5) - C,
+    A + (B<< 6) - C,
+    A + (B<< 7) - C,
+    A + (B<< 8) - C,
+    A + (B<< 9) - C,
+    A + (B<<10) - C,
+    A + (B<<11) - C,
+    A + (B<<12) - C,
+    A + (B<<13) - C,
     /* MSB here */
 };
 
@@ -182,7 +182,7 @@ int main(void) {
     /* Configure TIM1 for display strobe generation */
     TIM1->CR1 = TIM_CR1_ARPE;
 
-    TIM1->PSC = 1; /* Prescale by 2, resulting in a 16MHz timer frequency and 62.5ns timer step size. */
+    TIM1->PSC = 1; /* Prescale by 2, resulting in a 15MHz timer frequency and 66.7ns timer step size. */
     /* CH2 - clear/!MR, CH3 - strobe/STCP */
     TIM1->CCMR2 = (6<<TIM_CCMR2_OC3M_Pos) | TIM_CCMR2_OC3PE | (6<<TIM_CCMR2_OC4M_Pos);
     TIM1->CCER |= TIM_CCER_CC3E | TIM_CCER_CC3NE | TIM_CCER_CC3P | TIM_CCER_CC3NP | TIM_CCER_CC4E;

firmware/offset_test.py

@@ -11,25 +11,17 @@ if __name__ == '__main__':
     import argparse
 
     parser = argparse.ArgumentParser()
-    parser.add_argument('channels', type=str, help='olsndot channels to test, format: 0-3,5,7,8-10')
-    parser.add_argument('run_name', nargs='?', default=None)
+    parser.add_argument('run_name', nargs='?', default='auto')
     parser.add_argument('olsndot_port', nargs='?', default='/dev/serial/by-id/usb-FTDI_FT232R_USB_UART_A50285BI-if00-port0')
     parser.add_argument('buspirate_port', nargs='?', default='/dev/serial/by-id/usb-FTDI_FT232R_USB_UART_AD01W1RF-if00-port0')
+    parser.add_argument('-c', '--channels', nargs='?', default='auto', help='olsndot channels to test, format: 0-3,5,7,8-10')
     parser.add_argument('-d', '--database', default='results.sqlite3', help='sqlite3 database file to store results in')
     parser.add_argument('-m', '--mac', type=int, default=0xDEBE10BB, help='olsndot MAC address')
     parser.add_argument('-w', '--wait', type=float, default=0.1, help='time to wait between samples in seconds')
     parser.add_argument('-o', '--oversample', type=int, default=16, help='oversampling ratio')
+    parser.add_argument('-b', '--bits', type=int, default=None, help='number of bits to sample')
     args = parser.parse_args()
 
-    def parse_channels(channels):
-        for spec in channels.split(','):
-            if str.isnumeric(spec):
-                yield int(spec)
-            else:
-                low, high = spec.split('-')
-                yield from range(int(low), int(high)+1)
-    channels = list(parse_channels(args.channels))
-
     db = sqlite3.connect(args.database)
     db.execute("""
         CREATE TABLE IF NOT EXISTS runs (
@@ -55,18 +47,43 @@ if __name__ == '__main__':
 
     uut = Olsndot(args.mac)
     d = Driver(args.olsndot_port, devices=[uut])
-    uut.send_framebuf([0]*uut.nchannels)
     print('Connected to uut:', uut)
 
     run_name = args.run_name
-    if args.run_name is None:
-        names = [ n[4:] for n, in db.execute('SELECT name FROM runs WHERE name LIKE "test%"').fetchall() ]
-        run_name = 'test{}'.format(1+max(int(n) if str.isnumeric(n) else 0 for n in names))
+    if not str.isnumeric(args.run_name[-1]):
+        names = [ n[len(run_name):] for n, in db.execute(
+            'SELECT name FROM runs WHERE name LIKE ?||"%"', (run_name,)).fetchall() ]
+        names.append('0') # in case we get no results
+        run_name += str(1+max(int(n) if str.isnumeric(n) else 0 for n in names))
     with db:
         cur = db.cursor()
         cur.execute('INSERT INTO runs(name, uut_mac, timestamp) VALUES (?, ?, ?)',
                 (run_name, args.mac, time.time()))
         run_id = cur.lastrowid
+
+    nbits = args.bits if args.bits is not None else uut.nbits
+
+    def parse_channels(channels):
+        for spec in channels.split(','):
+            if str.isnumeric(spec):
+                yield int(spec)
+            else:
+                low, high = spec.split('-')
+                yield from range(int(low), int(high)+1)
+    if args.channels == 'auto':
+        for i in range(uut.nchannels):
+            fb = [0]*uut.nchannels
+            fb[i] = 0xffff;
+            uut.send_framebuf(fb)
+            time.sleep(0.2)
+            if bp.adc_value > 0.5:
+                break;
+        else:
+            raise ValueError('Cannot find active channel')
+        channels = [i]
+    else:
+        channels = list(parse_channels(args.channels))
+
     print('Starting run {} "{}" at {:%y-%m-%d %H:%M:%S:%f}'.format(run_id, run_name, datetime.now()))
     print('mac={:08x} channels={}'.format(args.mac, ','.join('{:02d}'.format(ch) for ch in channels)))
     print('[measurement id] " " [hex setpoint value] "(" [float duty cycle] ")" " " [reading (V)]')
@@ -84,7 +101,7 @@ if __name__ == '__main__':
     print('Zero cal: {:5.4f}V stdev={:5.4f}V'.format(mean, stdev))
 
     for ch in channels:
-        for i in range(uut.nbits):
+        for i in range(nbits):
             fb = [0]*uut.nchannels
             val = 1<<i
             duty_cycle = val/(2**uut.nbits)
@@ -105,7 +122,7 @@ if __name__ == '__main__':
                             run_id, channel, duty_cycle, voltage, voltage_stdev, timestamp
                         ) VALUES (?, ?, ?, ?, ?, ?)''',
                         (run_id, ch, duty_cycle, mean, stdev, time.time()))
-                print('{:08d} ch={} {:04x}({:6.5f}): {:5.4f} stdev {:5.4}'.format(
+                print('{:08d} ch={} {:04x}({:6.5f}): {:5.4f} stdev {:5.4f}'.format(
                     cur.lastrowid, ch, val, duty_cycle, mean, stdev))
 
     uut.send_framebuf([0]*uut.nchannels)

firmware/olsndot.py

@@ -112,8 +112,8 @@ class Olsndot:
 
     def __str__(self):
         st = self.fetch_status()
-        return '<Olsndot@{} {}.{} {}ch*{} up {}s vcc {:4.3}V temp {}C>'.format(
-                self.addr, self.fw_ver, self.hw_ver, self.nchannels, self.channel_format,
+        return '<Olsndot {}.{}@{} {}ch*{} up {}s vcc {:4.3}V temp {}C>'.format(
+                self.fw_ver, self.hw_ver, self.addr, self.nchannels, self.channel_format,
                 st.uptime_s, st.vcc_mv/1000, st.temp_celsius)
 
     @property