Microchip's AT21CS11 is a serial EEPROM device in a package with only two pins. There are also versions with more pins in more common packages, but these too only use two of their pins. The device connects to a system through a Single Input/Output (SI/O) wire that serves as both the communication and the power supply to the part.
Semiconductor manufacturers announcing new memory devices is quite common and usually reading the press release remains limited to a quick glance before discarding it. This almost also happened to the announcement from Microchip for their new AT21CS11 single wire, EEPROM (electrically erasable programmable read-only memory) device. Only after reading it a second time did I notice the ‘two-pin’ in the description.
AT21CS11 Block diagram (source: Microchip)
Indeed, opening the datasheet reveals a memory device in a package with only two pins. There are also versions with more pins in more common packages, but these too only use two of their pins. The device connects to a system through a Single Input/Output (SI/O) wire that serves as both the communication and the power supply to the part.
EEPROM with unique ID
The new device has 1 Kbit of EEPROM memory divided in four sectors of 256 bits each, a 64-bit serial number and 128 bits for extra user-programmable tracking memory. This extra memory is intended for storing unique identification and operating parameters, such as consumption and usage information, in locations that can be remote from the main electronics. Any, or all, of the memory sections can be permanently locked.
