Technical Success Stories: SD Card Customization & Data Integrity
“We are looking for the best duplicator SD card solution for our high capacity application.”
Background: A long-time customer and buyer of Delkin SD cards was expanding the use and data output of their application, and decided to test some content loading equipment (Duplicators). They had been adding content to SD cards for a series of years, but now they needed to increase volume, so new content loading equipment was added to meet new quotas. There were new orders coming in for their application and other areas of manufacturing had increased to meet the new demand. They began having failures on SD cards where content was loaded from the duplicators, and this data issue needed to be resolved fast.
Customer Story: Upon testing out the new duplicator equipment the OEM began seeing data failures occur in all the cards. They ran the SD cards on their old equipment and they functioned as intended, but with the new equipment there was a high failure rate. The OEM already owned the new duplicator equipment so there needed to be a way to figure out why the data failures were happening and what could be done to fix it. Going with other equipment was no longer an option. The Delkin Customer Applications Team stepped in to collaborate with the application manufacturer and come up with a solution.
Delkin Discovery: First, the customer contacted the duplicator manufacturer to confirm compatibility. The manufacturer ran several tests, and determined that the Delkin cards were failing during the read verification test, and not during the copying phase. The Duplicator maker issued a report confirming what we had seen, that the cards had compatibility issues with the new equipment.
The customer passed this information along to the Delkin Customer Applications Team and a case was opened to investigate the problem. First line of action was reproducing the exact same arrangement the customer was using. Through the exact reproduction of the steps taken, it was determined the cards were failing during the read verification step. Various tests were run, and the previous duplicator the customer used, which was duplicating Delkin cards with no issues, was also analyzed in parallel.
Delkin Solution: The signal integrity of the Delkin SD cards was meeting the correct timing specifications for the embedded system usage, and power draw and other specifications were within the correct range. During analysis, it was noted that the BUS strength of the card had been reduced slightly to save power. Among many options available in the initialization of a Delkin SD card is the option to save power this way. It was also noted that the cable on the initial duplicators was half the length of the cable on the new, high speed duplicators. This turned out to be the problem. The analysis showed the cabling distance between the card and the duplicator motherboard was causing the cards signal to weaken during reads. Since the duplicator supplier was unable to modify the length of the cable, Delkin customized the card by increasing the cards bus strength to prevent read verification errors during duplication.
Lesson Learned: In this situation, the card had been optimized for power, which caused the error. This is typically a feature that is preferred, but should not be overlooked when determining what may be behind a detected failure. Since the host manufacturer (in this case the duplicator maker) was unable to make a change to solve the problem, Delkin was able to modify the card. It was concluded that a customization of the card, rather than a customization within the host, or software, is faster and easier than other possible solutions. This is also a much more cost effective solution, and in this case saved the customer the significant cost of alternate resolutions. A new part number was issued on behalf of Delkin. The new customized SD card came complete with new initialization instructions and guaranteed the customer got cards with the added bus strength for all SD card orders moving forward.
Lean on Delkin’s Technical Team: Have you had a problem with your host storage? The Delkin Customer Applications Team stands at the ready to be your trusted adviser for your host critical storage. We have solved hundreds of complicated host failures and look forward to understanding your usage model for flash based Rugged Controlled Storage.