DESCRIPTION
The DS1222 BankSwitch Chip is a CMOS circuit designed to select one of 16 memory banks under software control. Memory bank switching allows for an increase in memory capacity without additional address lines. Continuous blocks of memory are enabled by selecting proper memory bank through a pattern recognition sequence on four address inputs. Custom patterns from Dallas Semiconductor can provide security through uniqueness and prevent unauthorized access. By combining the DS1222 with the DS1212 Nonvolatile Controller x16 Chip, up to 16 banks of static RAMs can be selected.

FEATURES
■ Provides bank switching for 16 banks of
   memory
■ Bank switching is software-controlled by a
   pattern recognition sequence on four address
   inputs
■ Automatically sets all 16 banks off on
   power-up
■ Bank switching logic allows only one bank on
   at a time
■ Custom recognition patterns are available to
   prevent unauthorized access
■ Full ±10% operating range
■ Low-power CMOS circuitry
■ Can be used to expand the address range of
■ microprocessors and decoders
■ Optional 16-pin SOIC surface mount package