Added MAX6921 shift register signal dumps.

MAX6921 signal dump that is from a prototype nixie clock
design for the AM335x-based Beaglebone.

Signed-off-by: Matt Ranostay <redacted>

diff --git a/vfd/max6921/README b/vfd/max6921/README
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+-------------------------------------------------------------------------------
+MAX6921 Shift Register
+-------------------------------------------------------------------------------
+
+This is a capture of data output to a MAX6921 high voltage shift register that
+was outputting data for a VFD clock.
+
+The signals were grabbed on a 28-pin PLCC chip (MAX6921) which outputs 20-bits
+that is crafted as a design for VFD applications.
+
+Logic analyzer setup
+--------------------
+
+The logic analyzer used was Open Bench Logic Sniffer (at 10Mhz):
+
+ Probe         MAX6921 Pin
+ --------------------------
+ 0              LOAD   
+ 1             DATA
+ 2             CLK
+ 3             BLANK (PWM Brightness Control)
+
+Data
+----
+
+The data contain various values for the VFD being driven, as reference at the
+prototype Nixie Cape for the Beaglebone.
+
+  Digit         Bit
+ --------------------------
+  0             1<<12
+  1             1<<19
+  2             1<<13
+  3             1<<18
+  4             1<<14
+  5             1<<17
+  6             1<<16
+  7             1<<15
+  8             1<<15
+  9             1<<11
+
+  Segment       Bit
+ ---------------------------
+  SEG_A         1<<0
+  SEG_B         1<<1
+  SEG_C         1<<2
+  SEG_D         1<<3
+  SEG_E         1<<4
+  SEG_F         1<<5
+  SEG_G         1<<6
+  SEG_H         1<<7
+
+
+References:
+-----------
+
+ * BeagleBoard.org Vendor Tree (https://github.com/beagleboard/kernel)
+ * Beagle Nixie GitHub (https://github.com/mranostay/beagle-nixie/)
+ * MAX6921 Datasheet (http://datasheets.maximintegrated.com/en/ds/MAX6921-MAX6931.pdf)
+
+The sigrok command line used was:
+
+  sigrok-cli --driver=ols:conn=/dev/ttyACM0 -d samplerate=10mhz  \
+             -samples=24576 -p 0=LOAD,1=DATA,2=CLK,3=BLANK -o max6921_data_10mhz.sr
+

diff --git a/vfd/max6921/max6921_data_10mhz.sr b/vfd/max6921/max6921_data_10mhz.sr
new file mode 100644 (file)
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Binary files /dev/null and b/vfd/max6921/max6921_data_10mhz.sr differ