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Simple design powers snazzy digital frame

Posted: 14 Jan 2009 ?? ?Print Version ?Bookmark and Share

Keywords:digital photo frame? minimum electronics? design simple? teardown Kodak EasyShare M1020?

The Kodak EasyShare M1020 offers lots of peripheral features, such as the ability to play videos and MP3 audio files, a user-friendly touch panel.

One of the fun parts about doing teardowns is getting to try the products out before taking them apart. This product, however, the Kodak EasyShare M1020 10-inch digital frame, didn't have any particular appeal to me, so it sat on my shelf unopened for a while.

One day, while preparing for a party for one of my kids (my son's high school graduation), I noticed the frame sitting there, and I decided to put it to use. I loaded up a bunch of pictures of my son, and I was astounded at the quality of the display. One of the frame's key features is the touch capability. It uses an intuitive menu that sits around the LCD's edge. That menu disappears when displaying the photos.

I had bought a smaller, albeit less expensive digital frame a few years ago, and was frankly underwhelmed by its performance. So it doesn't get used too often. But the quality of the Kodak frame really amazed me. From that point until it underwent the hammer and screwdriver treatment, it got lots of use.

Once apart, it was evident that the electronics in the frame were held to a minimum. In fact, there were only two key componentsthe Amlogic AML6213D microprocessor and the Cypress Semiconductor CY8C20434. Other ICs include two memory chips: an EtronTech EM639165TS SDRAM that's used in conjunction with the Amlogic part and a Hynix HY27UF081G2A SLC NAND chip for storing code store and images.

The frame comes with 128 Mbytes of built-in storage and an SD card interface. The internal memory is programmed via USB, but it's much easier to stick your photos onto an SD Card and plug the card into the frame.

In the design, the AML6213 is essentially the workhorse part, as it handles the memory card interface, the image file translation, the image formatting for display, and the driving of the LCD. The main function that the CapSense part is used for is to detect the capacitance on the LCD to identify whether a finger is present. A second function is that it acts as an interface to the main processor, which occurs over an I?C bus.

Looking at the backside of the board shows how simple it is, at least from an IC layout perspective.

Size matters
This frame was built in China by an ODM, one of a few employed by Kodak. Multiple frames with varying size displays are in development. On this model, Cypress worked with its local distributor, Future Electronics, on the PCB design and the schematics. Cypress also developed tests and tools for the ODM. Finally, Cypress helped Kodak qualify the manufacturing process.

Regardless of the size of the display, a variation of the CapSense part can still be used. The only difference is that there are more I/O pins when the larger display is used. For example, the 10-inch display uses a CapSense with 15 I/O pins, while the 8-inch display requires a CapSense with just 12 I/O pins.

"When working with Kodak, they require us to be extra careful about the firmware footprint," says Ken Xu, a Cypress field applications engineer based in Shenzhen, China, who was deeply involved in the design. "To minimize the firmware size, we used a software filter. It also helped us to get the best reliability when identifying the presence of the finger. The CapSense also lightens the workload on the host processor by identifying which inputs are being deployed."

There are only two key components driving the Kodak EasyShare M1020 10-inchi digital frameAmlogic AML62130 microprocessor and Cypress CY8C20434. (Click to view larger image.)

Right partner
Kodak started working on the frame concept in Q3 07, which took about a quarter to complete. With the concept wrapped up, Kodak began the search for an ODM. By Q4, a decision was made to go with Future Electronics, and timelines were established.

"Originally, we weren't designed into the frame. Kodak had opted for Quantum, one of our competitors," says Xu. "But the ODM that Kodak chose was someone we had worked with in the past and they convinced Kodak to go with Cypress."

One of the key design criteria was reliability, which could be harder than it sounds when you're working with a relatively large noise from the LCDthe bigger the screen, the bigger the noise. This noise caused the software to make wrong judgments. So the Cypress designers came up with the software filter to handle the data and remove the potential errors.

Most of the firmware was architected by Future Electronics. IP protection wasn't an issue, thanks to the CapSense part. Amlogic helped debug the code. If warranted, firmware updates could be made in the field.

The CapSense helps reduce the component count in a capacitive sensing solution, requiring just one external resistor on each of the sensing lines. The simple solution also helps increase yields during production.

Richard Nass is editor-in-chief of Embedded Systems Design magazine and editorial director of TechInsights' Embedded Group.

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