To demonstrate some of the new commands from the new firmware 5.2, we interfaced the DE-DP014 from Sure-electronics. This is a single, SPI-like controllable 1.8″ single 5×7 dotmatrix. It has an on-board PIC controller which stores a special ASCII font. The package consist of two units, a simple demo board and two 10-pin cables. Sure provides a decent manual, which is only downloadable from their store.

The DE-DP014 has two 10-pin shrouded headers to provide power, brightness control, data-in, data-out, and clock. The top header is the input and the bottom one the output. Up to 20 units can be daisy chained (according to the manual, we don’t earn enough to buy such an amount!).

Get a Bus Pirate for $30, including worldwide shipping at Seeed Studio. Adafruit also has the Bus Pirate and probe cables in stock and ready to ship.

Connections

Bus Pirate v3a
Firmware v5.2 (r422) Bootloader v4.1
DEVID:0x0447 REVID:0x3043 (B5)

http://dangerousprototypes.com

HiZ>

We used an external power supply to power the device. The manual states the maximum power draw is 500mA, the Bus Pirate only can supply up to 160mA, so we didn’t dare to use it. On the back there are extra power supply connections. Next we connected the MOSI, CLK and GND to the unit. We also connected AUX to the dimmer input. We double checked the connections and powered everything up.

Setup

HiZ> m
1. HiZ
...
7. 3WIRE
8. KEYB
9. LCD
x. exit(without change)
(1)> 7
Set speed:
1. ~5KHz
2. ~50KHz
3. ~100KHz
4. ~400KHz
(1)> 2
Select output type:
1. Open drain (H=Hi-Z, L=GND)
2. Normal (H=3.3V, L=GND)
(1)> 2
Ready.
3WIRE>

We switched into raw3wire mode.

HiZ> m 7 2 2
R3W (spd hiz)=( 1 0 )
Ready.
3WIRE>

Alternatively we could use the shorthand form (not for the fainthearted!) to switch modes.

Always be sure to check if the settings are OK. The current settings should be printed before ‘Ready’. In this case speed=1 (0=5KHz, 1=50KHz, 2=100KHz, 3=400KHz) and HiZ=0 (0=off, 1=on). The settings are printed like they are in the code!

3WIRE> L
MSB set: MOST sig bit first
3WIRE>

The manual stated that the data should be MSB first (this is why we can’t use the hardware SPI module).

<pre>3WIRE> g 100 50
PWM active
3WIRE>

Also the dimmer input should have a PWM signal (or just a ‘1′) to display anything, we used a 100KHz with 50% duty-cycle.

Interfacing

3WIRE> "?"
WRITE: "?"
3WIRE>

Note that we used the concatenated version of this command and now finally we got to the point to display something! We’re gonna use a new feature of the v5.x firmware to easily display text strings. We introduced the ” command which send the string one-byte-a-time to the bus.

Say Cheese! Actually we wanted to show a ! but it was too hard to see on the pictures.

3WIRE> "STOP"
WRITE: "STOP"
3WIRE>

BTW we wonder what will happen if we installed four of these in our car and issued this command.

Here’s a follow up on the PIC programming adapter from SURE we posted a few weeks ago. mizch mentioned that SURE’s shipping can add 30-40% to the final price, and suggested browsing eBay to see real prices. We found it on eBay for $9.99 with free shipping, and ordered it on June 28. The board shipped June 30, and arrived July 8 in a familiar Seeed-style box.

The board is good quality. It has acrylic plates on the top and bottom, the circuit board is in the middle. We’d use this style of case on a future project.

The top layer of acrylic is cut away to access the ZIF sockets and quick release levers. The cuts are too small for us to get to the levers so we removed the top plate by unscrewing it.

We’ll be using this board to test lots of different PICs with piratePICprog, the new PIC programmer for the Bus Pirate.

will_j posted a Bus Pirate script that controls a Sure Electronics 8×32 LED marquee:

Here’s a quick and dirty perl script to display ‘BPv3′ on a Sure Electronics 8×32 LEd Matrix display.

You can also use a 16×24 display if you change the second command code to 44 from 40.

Any improvements gratefully received – i.e. a nice character lookup table process would be good!

View a copy in the Bus Pirate scripts folder. We demonstrated a slightly different Sure LED matrix a in a demo: post a few weeks ago.

Thanks for the tip!

This is an old version, see the latest version on the documentation wiki.

You may have come across this 16×24 LED matrix board on eBay or at Sure Electronics. Each board has three 8×8 LED blocks and a controller to drive them. A simple three-wire serial interface toggles each LED and configures the overall brightness of the board. Up to four boards can be chained through 2×10 pin headers on the back, a connector cable was included with each board.

We used the Bus Pirate to test the board and learn its protocol before using it with the web platform (more on that later). Grab the datasheet and follow along below.

This is the first of a new weekly series that demonstrates devices with the Bus Pirate. Come back next Monday for another all new demo.

Device: Sure LED matrix board.
Bus: 3 wire, SPI-like bus (use pull-up resistors for 5volt interfacing).
Power requirements: 5 volts.
References: datasheet [PDF], demo code.
Complete Bus Pirate session log for this demonstration.

We connected the Bus Pirate to the board as shown in the table above.

A 5volt supply powers the LEDs and controller, we used the Bus Pirate’s on-board supply. The controller requires 5volt signal levels, but the Bus Pirate’s output is only 3.3volts. No problem, we used the on-board pull-up resistors and high-impedance output mode to interface the controller at 5volts. Remember to connect the Vpu pin to the 5volt power supply.

Three wires control the matrix. Data is entered on the data pin, and each bit is read when the WR pin is high. The chip select (CS) signal activates the data interface on the LED controller chip.

Multiple matrix boards can be chained together, but each needs a separate CS signal. On the front of the PCB there’s a DIP switch that sets the chip select number for that board. Be sure to set it to the CS pin number you’re using, we used CS1. You could use the Bus Pirate AUX pin to toggle a second chip select on another board.

Bus Pirate setup

We used raw3wire mode to interface the board because some of the commands require single-bit operations that aren’t supported in the SPI library.  Open the mode menu (m) and choose raw3wire. Configure it for any speed, with open drain/high-impedance outputs.

In raw3wire mode turn on the power supply (W), and enable the pull-up resistors (P). Get a voltage report (v) to make sure the pull-up resistors (Vpu) are correctly powered at 5volts.

LED board configuration

We need to configure the controller before playing with the LEDs. The data sheet isn’t entirely clear about the setup sequence and proper values. We couldn’t have done it without following this sample source code.

RAW3WIRE>[-^_^^ 24 ^ ]
CS ENABLED
DATA OUTPUT, 1
0×01 CLOCK TICKS
DATA OUTPUT, 0
0×01 CLOCK TICKS
0×01 CLOCK TICKS
WRITE: 0×18
0×01 CLOCK TICKS
CS DISABLED
RAW3WIRE>

[ lowers the chip select pin and tells the controller to listen for data.

Each configuration command begins with a three bit sequence of one high bit (1) and two low bits (0). The Bus Pirate syntax for this is -^_^^. - raises the data line to 1, ^ raises and lowers the clock line to enter the high bit. _ lowers the data line, and ^^ ticks the clock twice to enter two low bits.

Decimal value 24 configures the controller clock, we enter it as a number and 8bits are sent. Commands end with one more clock pulse (^), though the data values is ignored. ] raises the chip select signal which disables the controller data interface and activates the new command.

A list of configuration commands follows, the Bus Pirate output looks similar to that above.

The only really interesting command is the one that sets the PWM brightness level. See the table on page 12 and 13 of the datasheet.

Control the LEDs

RAW3WIRE>[-^_^-^ _^:7 0b11111111:48]
CS ENABLED
DATA OUTPUT, 1
0×01 CLOCK TICKS
DATA OUTPUT, 0
0×01 CLOCK TICKS
DATA OUTPUT, 1
0×01 CLOCK TICKS
DATA OUTPUT, 0
0×07 CLOCK TICKS
WRITE: 0xFF , 0×30 TIMES
CS DISABLED
RAW3WIRE>

Write commands start with the 3 bit sequence 101, and a 7 bit address representing a cluster of LEDs to modify. Each address is mapped to a group of four LEDs in the matrix, a minimum of four LEDs are set with each write command.

We create the write command with -^_^-^_:7. This is similar to the configuration syntax. -^_^-^ sends 101, _:7 sends the LED write address 0000000. We use a repeat command (^:7) to send seven clock pulses instead of typing each one. With 96 LEDs to address, the repeat command will come in very handy.

In these examples we always start writing from the first LED, but you can use the 7 bit address to modify any LED cluster in the matrix. For example 101 0000001 (-^_^-^ _:6 -^) begins modification of the second LED cluster (LEDs 5, 6, 7, and 8).

The LEDs have a simple on-off control. Each bit following the command and address sequence controls one LED. There are 6, 8×8 matrices, or 384 LEDs. Each LED is controlled by one bit, so 48 bytes (384/8) are needed to set every LED on the board. We set all the LEDs on by writing 0b11111111 forty-eight times.

RAW3WIRE>[-^_^-^ _^:7 0x00:48]
CS ENABLED
DATA OUTPUT, 1
0×01 CLOCK TICKS
DATA OUTPUT, 0
0×01 CLOCK TICKS
DATA OUTPUT, 1
0×01 CLOCK TICKS
DATA OUTPUT, 0
0×07 CLOCK TICKS
WRITE: 0×00 , 0×30 TIMES
CS DISABLED
RAW3WIRE>

Next we turn the LEDs off by clocking in all 0 bits.

RAW3WIRE>[-^_^-^  _^:7   -^_^^^]
CS ENABLED
DATA OUTPUT, 1
0×01 CLOCK TICKS
DATA OUTPUT, 0
0×01 CLOCK TICKS
DATA OUTPUT, 1
0×01 CLOCK TICKS
DATA OUTPUT, 0
0×07 CLOCK TICKS
DATA OUTPUT, 1
0×01 CLOCK TICKS
DATA OUTPUT, 0
0×01 CLOCK TICKS
0×01 CLOCK TICKS
0×01 CLOCK TICKS
CS DISABLED
RAW3WIRE>

The LEDs are not individually addressable, but they can be toggled in chunks of four. In this command we set the first LED on (-^) and the remaining three LEDs in the group off (_^^^).

RAW3WIRE>[-^_^-^  _^:7   _^-^_^^]
CS ENABLED
DATA OUTPUT, 1
0×01 CLOCK TICKS
DATA OUTPUT, 0
0×01 CLOCK TICKS
DATA OUTPUT, 1
0×01 CLOCK TICKS
DATA OUTPUT, 0
0×07 CLOCK TICKS
DATA OUTPUT, 0
0×01 CLOCK TICKS
DATA OUTPUT, 1
0×01 CLOCK TICKS
DATA OUTPUT, 0
0×01 CLOCK TICKS
0×01 CLOCK TICKS
CS DISABLED
RAW3WIRE>

This command lights the second LED, and disables the first, third, and fourth.

RAW3WIRE>[-^_^-^  _^:7   -^^^^]
CS ENABLED
DATA OUTPUT, 1
0×01 CLOCK TICKS
DATA OUTPUT, 0
0×01 CLOCK TICKS
DATA OUTPUT, 1
0×01 CLOCK TICKS
DATA OUTPUT, 0
0×07 CLOCK TICKS
DATA OUTPUT, 1
0×01 CLOCK TICKS
0×01 CLOCK TICKS
0×01 CLOCK TICKS
0×01 CLOCK TICKS
CS DISABLED
RAW3WIRE>

Finally, a command to turn all LEDs in the first cluster of four. This could also be entered with the repeat command as [-^_^-^  _^:7   -^:4].

Notes

Like the Sure Microchip PICkit2 clone photographed by Scorpia, this Sure device was covered in flux.

If you have any demonstration requests, please leave them in the comments. If we demo your device, we’ll send you a free PCB.