Patent ID: 7549580
Filing Date: 2009-06-23
Classification: G06F,G11C,H04L

Abstract:
1. A host device configured to read and write information from and into a card and to supply a supply voltage that belongs to a first voltage range or a second voltage range having an upper limit which is lower than a lower limit of the first voltage range, the host device configured to issue to the card a voltage identification command including a voltage range identification section, an error detection section, and a check pattern section, wherein the voltage range identification section includes information indicating which one of the first voltage range and the second voltage range the supply voltage belongs, the error detection section has a pattern configured to enable the card which has received the voltage identification command to confirm whether the voltage identification command is valid or invalid, the check pattern section has a preset pattern, the host device changes an initialization command into a new memory initialization command depending on whether the host device receives a response to the voltage identification command, the initialization command including a voltage window section instructing the card to initialize a memory, the new memory initialization command including the voltage window section and a section other than the voltage window section, and the host device issues the new memory initialization command to the card.