projects / sigrok-dumps.git / blame
| Commit | Line | Data |
|---|---|---|
| 1b4691d8 MR |
1 | ------------------------------------------------------------------------------- |
| 2 | MAX6921 Shift Register | |
| 3 | ------------------------------------------------------------------------------- | |
| 4 | ||
| 5 | This is a capture of data output to a MAX6921 high voltage shift register that | |
| 6 | was outputting data for a VFD clock. | |
| 7 | ||
| 8 | The signals were grabbed on a 28-pin PLCC chip (MAX6921) which outputs 20-bits | |
| 9 | that is crafted as a design for VFD applications. | |
| 10 | ||
| 11 | Logic analyzer setup | |
| 12 | -------------------- | |
| 13 | ||
| 14 | The logic analyzer used was Open Bench Logic Sniffer (at 10Mhz): | |
| 15 | ||
| 16 | Probe MAX6921 Pin | |
| 17 | -------------------------- | |
| 18 | 0 LOAD | |
| 19 | 1 DATA | |
| 20 | 2 CLK | |
| 21 | 3 BLANK (PWM Brightness Control) | |
| 22 | ||
| 23 | Data | |
| 24 | ---- | |
| 25 | ||
| 26 | The data contain various values for the VFD being driven, as reference at the | |
| 27 | prototype Nixie Cape for the Beaglebone. | |
| 28 | ||
| 29 | Digit Bit | |
| 30 | -------------------------- | |
| 31 | 0 1<<12 | |
| 32 | 1 1<<19 | |
| 33 | 2 1<<13 | |
| 34 | 3 1<<18 | |
| 35 | 4 1<<14 | |
| 36 | 5 1<<17 | |
| 37 | 6 1<<16 | |
| 38 | 7 1<<15 | |
| 39 | 8 1<<15 | |
| 40 | 9 1<<11 | |
| 41 | ||
| 42 | Segment Bit | |
| 43 | --------------------------- | |
| 44 | SEG_A 1<<0 | |
| 45 | SEG_B 1<<1 | |
| 46 | SEG_C 1<<2 | |
| 47 | SEG_D 1<<3 | |
| 48 | SEG_E 1<<4 | |
| 49 | SEG_F 1<<5 | |
| 50 | SEG_G 1<<6 | |
| 51 | SEG_H 1<<7 | |
| 52 | ||
| 53 | ||
| 54 | References: | |
| 55 | ----------- | |
| 56 | ||
| 57 | * BeagleBoard.org Vendor Tree (https://github.com/beagleboard/kernel) | |
| 58 | * Beagle Nixie GitHub (https://github.com/mranostay/beagle-nixie/) | |
| 59 | * MAX6921 Datasheet (http://datasheets.maximintegrated.com/en/ds/MAX6921-MAX6931.pdf) | |
| 60 | ||
| 61 | The sigrok command line used was: | |
| 62 | ||
| 63 | sigrok-cli --driver=ols:conn=/dev/ttyACM0 -d samplerate=10mhz \ | |
| 64 | -samples=24576 -p 0=LOAD,1=DATA,2=CLK,3=BLANK -o max6921_data_10mhz.sr | |
| 65 |