CompactFlash Cards

Always format your memory card in the persistor with PicoDOS.

Persistor recommends Western Digital SSD-Cnn(M or G)I-3500 memory cards while available. This series was discontinued in 2011.

If 3500 series memory cards can not be obtained, Persistor recommends SSD-CnnGI-4600 up to 4GB, and SSD-CnnGI-4500 above 4GB.

Here is a notice of the change from 3500 series to 4600 and 4500 cards. Note the increased current drains.

Please be aware that many memory cards may appear to work in a Persistor product but may have qualities that might cause problems. Such qualities might be current drain, bus conflict, time to ready, wear leveling, type of flash and non-standard formatting.

Also please be aware that the Persistor CF2 can only recognize volumes up to 128GB (137,438,953,472 bytes). Follow this link to more information about file size limits.

In 2007, Persistor identified two rare but possible corruption problems when using power-cycling sleep modes. One problem was specifically shown to exist in 3005 series SiliconDrive memory cards and not demonstrable in 3500 series cards. The second problem required moving to PicoDOS 4.03 (CF1 or CF2) or modifying your program with a simple timing change. Review this notice if you are using 3005 series SiliconDrive memory cards, or CF1s or CF2 with PicoDOS lower than 4.03.

In April 2005, Persistor moved to the SiliconSystems brand card when SanDisk discontinued their OEM series of cards. At that time Persistor began manufacturing the CF1 and CF2 with a different value pull up on the data bus and updated PicoDOS (>4.x) to minimize the current drain. If you are using a CF1 or CF2, manufactured before April 2005, with WD 3500 series SiliconDrive memory cards, you may want to review this document for details.