PCF7931 - ETC

PCF7931 (PCF7930 - PCF7935) Memory Organisation

PCF7930/31/35 Memory organisation Memory structure Control memory flags of block 0 • Password (Bytes 0..6) The password is 56 bits long. If the pasword function has been ativated by the PAC flag, the pattern being written in this area must be transmitted by the base station with every program command. PCF7930/31/35 1 • Password Active Flag PAC (Byte 7) .

Features

pattern is used by the calculation unit during Authentication Mode. PCF7930/31/35 2
• Identifier On/Off, Identifier Lock IDL (Byte 28) / PCF7935 / The lower nibble of this memory falg enables/disables the general Identifier function, i.e. The transmission of the IDE pattern at power-on reset and soft-reset. The flag is evaluated as “active” for two or more bits being 1, it is evaluated as “inactive” for less then two bits being 1. The higher nibble of this memory flag locks the IDE pattern area and the IDL flag irreversibly against any program access. Therefore the enable/disable status .