Back in July, Joel Johnson of BoingBoing Gadgets interviewed Peter Griffin, a Deputy Editor for Esquire. The interview focuses on how Esquire will use E-Ink in it’s October 2008, 75th Anniversary edition. Peter speaks about how they are looking forward to seeing what hackers will do to the display, saying “The data will be baked into the circuitry. Figuring out how to reprogram the e-paper controller or installing an entirely new one will be up to the hackers.” The issue just hit newsstands today and like many other hackers across the country I dutifully snagged a copy and proceeded to slice it up and mess with its innards.
Upon first glance, especially when looking at lo-res web videos of the display in action it appears as if Esquire has magically procured a full color E-Ink display. Alas, Esquire just overlaid a transparent coloured overlay on top of the monochrome E-Ink display.
The second E-Ink display is located on the inside cover, in an ad for the Ford Flex. This display makes the image of the Flex appear to be moving – or at least it tries to.
We gain access to the displays and the board that runs them by running a knife along the top, inside and bottom of the cover which then folds out to the left. Removing the foam insert reveals the bottom E-Ink display.
Looking at the board we see that it’s a very simple, 2-layer PCB made by Zuhai Forewin with only 3 main ICs of which 2 are the same chip – an 8-stage shift-and-store bus register IC (NXP HEF4094BT) made by NXT Philips with the other chip being an 8-bit PIC microcontroller (PIC 12F629 – 4.8mb PDF) made by Microchip. The board and displays are powered by six 3v Lithium Coin batteries (model CR2016) which according to Esquire should provide you with around 90 days of blinking goodness.
As you may have assumed from the pin count and look of the displays – they appear to be segmented. That is, they are not made up of a grid of addressable pixels that can be turned on and off individually but are instead made up of several regions that may be turned on and off independently. This essentially means that for our purposes these displays are useless junk unless your project entails blinking “The 21st century begins now 
” on and off. Since I have no real interest in such a device this is where my analysis will stop. Those of you who wish to play with this for purely educational purposes you should be able to reprogram the PIC controller to change the blink order and timing of both displays, although it will probably require a chip programmer of some sort.
For a few more pictures of this teardown check out my SmugMug Gallery.
When I first read the Engadget post about the magazine being available I knew I would be driving around all day to find a copy that I could hack. I finally got a few copies and ripped one to shreds as soon as I got home.
Firstly, they did not use the active matrix version of the E-Ink display. It is a segmented version. This means that you can not make it do kindle like things. You must use the existing segments. The magazine contains two of these 2×5″ displays. The cover display has 11 segments while the inside display has 3. They are both black and ‘white’ (aka grey) displays although several shades seem possible by varying the switch voltage timing. The color areas are created with a transparent overlay that, of course, is always present.
(Note: These probably do not match the CN1 and CN2 pin outs)
COVER DISPLAY SEGMENTS
1. “THE 21ST CENTURY”
2. “BEGINS”
3. 1st box after “BEGINS”
4. 2nd box after “BEGINS”
5. 3rd box after “BEGINS”
6. Both boxes (left and right) of “NOW”
7. “NOW”
8. The circle arrow
9. Bottom box 1
10. Bottom box 2
12. Bottom box 3
INNER DISPLAY SEGMENTS
1. Left side 2 of 6 ‘wheel’ segments on both ‘wheels’
2. Middle 2 of 6 ‘wheel’ segments on both ‘wheels’
3. Right side 2 of 6 ‘wheel’ segments on both ‘wheels’
The cover display uses a 12 line ribbon connector while the inner display uses a 6 line ribbon with only 4 lines that are completed. One line on each display is a common connection while the others are simple on/off lines. Applying -15 volts turns the segment white while 15 volts turns the segment black.
THE ELECTRONICS
The circuit board is very simple with only a few components. There are six CR2016 3V batteries, 2 connectors, 2 HEF4094BT 8 stage shift-and-store bus register chips, 1 12F629 Flash based 8bit CMOS microcontroller, 26 resistors, 2 capacitors and 3 transistors. The 12F629 controls 3 transistors that drive the STROBE, DATA and CLOCK pins, at 15v, of the HEF4094BTs. The HEF4094BTs are connected in a cascade fashion to provide 16 latching registers that directly drive the EInk displays.
WHAT DOES IT ALL DO?
The Batteries:
5 of the 6 batteries (B1-B5) are connected in series to provide the 15v driver voltage that is used to change the segments from black to white and back. The other battery (B6) supplies the 3 volts needed to run the microcontroller. The B1-B5 series and B6 both share a common ground.
The PIC
U1 is the Microcontroller. This device controls the sequence of the changes.
Pin 1 is Vdd ( 3vdc).
C1 is used as a noise filter for the power.
Pin 2 is not used.
Pin 3 is not used.
Pin 4 is used for initial programming only.
Pin 5 drives Q3 through R5.
This drives the U3 and U3 STROBE (STR) lines causing the shift register data to be stored in the storage register.
Pin 6 drives Q2 through R3.
This drives the U2 and U3 CLOCK (CP) lines which allows serial programming of each register bit prior to storage.
Pin 7 drives Q1 through R1.
This drives the U2 DATA (S) line. U3 Data is connected to the O’s (PIN 10) of U2 which is a serial output.
pin 8 is Vss(GND).
The Transistors
Q1 drives the DATA (D) line of U2 and is driven by U1 Pin 7.
Q2 drives the CLOCK (CP) lines of U2 and U3 and is driven by U1 Pin 6.
Q3 drives the STROBE (STR) lines of U2 and U3 and is driven by U1 pin 5.
Q1-Q3 base pins are connected to common ground.
R1,3,5 are used for current limiting to protect U1 outputs.
R2,4,6 are pull-up resistors for Q1-3 causing the output to be 15V when off and ground when on.
C3 is a noise filter for the pull-up power rail.
The Shift Registers
U1 and U2 drive the displays. They are programmed by U1 via a serial bus. The parallel outputs we’ll look at from the perspective of the CN1 and CN2 connectors. These work as a marching train of bits. When the clock goes HI all bits are shifted right and the first one is set the whatever DATA is set to and the last bit falls off the end ad disappears. These bits cascade from U2 to U3 for a total of 16 bits. If the STROBE pin is HI then all of the shift registers are also stored in the storage registers which will stay the same until the next HI STROBE. In this application, 16 values are shifted in to the shift registers by the PIC (U1) then STROBE is set HI storing all the values on the next CLOCK HI and causing the display to change. Here are the inputs.
Pin 1 STROBE (STR)
This is controlled through Q3 via U1 Pin 5.
Pin 2 DATA (S)
This is controlled through Q1 via U1 Pin 7 on U2 only. U3 Data is received from the Pin 10 on U2, in effect, cascading the second shift register chip.
Pin 3 CLOCK (CP)
This is controlled through Q2 via U1 Pin 6.
Pin 4 Parallel Output 0 (O0) (See CN1 and CN2 description)
Pin 5 Parallel Output 1 (O1) (See CN1 and CN2 description)
Pin 6 Parallel Output 2 (O2) (See CN1 and CN2 description)
Pin 7 Parallel Output 3 (O3) (See CN1 and CN2 description)
Pin 8 Ground (VSS)
R10 and R12 are 0 ohm resistors (jumpers) connecting U2 and U3 to the common ground bus.
Pin 9 Serial Output (Os)
Pin 10 Serial Output Inverted (O’s)
Pin 11 Parallel Output 7 (O7) (See CN1 and CN2 description)
Pin 12 Parallel Output 6 (O6) (See CN1 and CN2 description)
Pin 13 Parallel Output 5 (O5) (See CN1 and CN2 description)
Pin 14 Parallel Output 4 (O4) (See CN1 and CN2 description)
Pin 15 Enable Output (EO)
This pin is wired HI at all times allowing the values in the storage register to always be active. When the storage value changes the display changes. (most of the time. See the section on how the display works for more details)
Pin 16 15VDC (VDD)
R9 and R11 are 2.4k ohm resistors that act as current limiters connecting U2 and U3 to the 15vdc bus.
The Connectors
Sorry, I ran out of time to map these pins out.
The Displays
The display segments change when the polarity of the voltage applied to them changes. Each segment has a drive pin and a common pin. All the segment common pins (on each display) are tied together. If 15V is applied to a segments drive pin and the common pin is grounded then the segment turns black. If the drive pin is grounded and the common pin is 15v then the segment turns white. (The colors may be reversed as I have not tested this yet). If both the drive and common pins are LOW or HI then nothing happens, IE it stays the same.
driver common
15v—-*—-gnd
15v—-?—-15v (stays the same)
gnd—-O—-15v
gnd—-?—-gnd (stays the same)
If you want to set some segments to white you will set the drive pins for those segments to LOW then set the rest of the drive pins and the common pin HI. The next STROBE HI will change the display.
All of this means that you can not set black and white segments at the same time. It is either black and same or white and same.
PARTS LIST
U1 Microchip 12F629
U2-3 NXP HEF4094BT
Q1-3 W1P 83
C1 Unknown value
C2 Not Used
C3 Unknown value
CN1 12 pin connector
CN2 6 pin connector
B1-6 Lithium CR2016 3V
R1,3,5 56K ohms
R2,4,6 1M ohm
R7,10,12 0 ohm (jumper)
R8 10K ohms
R9,11 2k4 ohms (2400)
R13-28 220 ohms
REFRENCES
HEF4094BT – 8 Stage Shift-and-Store Bus Register
http://www.datasheetcatalog.org/datasheet/philips/HEF4094BN.pdf
12F629 – 8-Pin FLASH-Based 8-Bit CMOS Microcontroller
http://www.datasheetcatalog.org/datasheets2/50/5044095_1.pdf
Any clue how flexible this will become in the future? The magazine’s implementation is too stiff to have widespread applications.