As we mentioned in our earlier post on the Esquire E-Ink cover, we have uncovered some additional details regarding the operation of this interesting E-Ink evaluation board set. There are two eight-stage shift-and-store bus registers (HEF4094BT) that drive each of the two E-Ink panels. The PIC12F629 controls the state of the HEF4094BT outputs: positive voltage, negative voltage, high impedance off, and shift register stage.
Please download these datasheets for more information about these two ICs:
You can also examine the content of the hex file that is programmed on the PIC12F629. You will need these products for reading the hex file:
- PICkit 2 (#DV164120) datasheet
- Mouser (#579-DV164120; $49.99)
- Right angle 6-pin header Molex .100 K.K. connector (Mouser #538-22-28-8060; $0.43)
- Jumper wires, male (SparkFun Electronics #PRT-08431; $3.95)
- Jumper wires, female (SparkFun Electronics #PRT-08430; $3.95)
- Microchip MPLAB IDE #SW007002
1. Solder the 6-pin header to jumper J1 on the E-Ink PCB. There are only five holes on the PCB for this header. Therefore, leave the extra sixth pin unsoldered off to the side of the PCB.
2. Attach the male and female jumpers together.
3. Insert five male jumpers into the ICSP connector on the PICkit 2 programmer. Route the female jumpers to the 6-pin J1 header on the E-Ink PCB. Use this chart for connecting the jumpers:
|J1 Pin||Signal||ICSP Pin|
4. Connect the PICkit 2 to the USB port of a PC and start the PICkit software.
5. Click the "Read Device + Export Hex File" button. Save the Hex file and exit the PICkit 2 app.
6. Start the Microchip MPLAB IDE and import the hex file that you saved in step 5.
7. In the View menu, click on Program Memory. Your hex file will be disassembled and can be saved as a text file.
If you come up with any additional information regarding the Esquire E-Ink cover, please post your findings in the Comments section.
The segments of the displays require + or - 15 V to fully change state. You can apply lower voltages to achieve intermediate levels (grayscale). The leftmost conductor in the ribbon cable that comes from each display seems to be the common for each "segment" I haven't done it but I thought it would be cool to use the three segment display (for the Ford add) and do a grayscale transition from one segement to the next giving the illusion of flow from one end to the other.
I realize that variable voltage would be difficult to implemtent on this pc board, perhaps by playing with the timing of the output of the shift registers, one could achieve the same effect. It is obvious that the trasition is somewhat slow, otherwise this technology could be used to display video.
There's another way, which I used, and involves tapping directly into the solder pads of the connector, bypassing the onboard circuitry altogether. This is useful if you wanted to take the screen off and use it as a standalone, or if you wanted to use another device. Anyway, I found that it was possible to turn the segments on and off with just -5 and +5 volts relative to ground (0). Knowing that, I used an Arduino to forward and reverse bias the pins, and wrote a little program to control it. It's cool because the screen keeps its state without any battery power.