ACE24C32B Datasheet, PDF (4/18 Pages) ACE Technology Co., LTD. – Two-wire Serial EEPROM

ACE24C32/64B
Two-wire Serial EEPROM
Pin Descriptions
Device/Page Addresses (A2, A1 and A0):
The A2, A1 and A0 pins are device address inputs that are hard wired for the ACE24C32B/ACE24C64B.
Eight 32K/64K devices may be addressed on a single bus system (device addressing is discussed in
detail under the Device Addressing section).
Serial Data (SDA):
The SDA pin is bi-directional for serial data transfer. This pin is open-drain driven and may be
wire-ORed with any number of other open-drain or open- collector devices.
Serial Clock (SCL):
The SCL input is used to positive edge clock data into each EEPROM device and negative edge clock
data out of each device.
Write Protect (WP):
The ACE24C32B/ACE24C64B has a Write Protect pin that provides hardware data protection. The
Write Protect pin allows normal read/write operations when connected to ground (GND). When the Write
Protect pin is connected to V_CC, the write protection feature is enabled and operates as shown in the
following Table 2.
WP Pin Status
At V_CC
At GND
Part of the Array Protected
ACE24C32B
ACE24C64B
Full (32K) Array
Full (256K) Array
Normal Read / Write Operations
Table 2 Write Protect
Memory Organization
ACE24C32B, 32K Serial EEPROM:
Internally organized with 128 pages of 32 bytes each, the 32K requires an 12-bit data word address for
random word address.
ACE24C64B, 64K Serial EEPROM:
Internally organized with 256 pages of 32 bytes each, the 64K requires an 13-bit data word address for
random word address.
Device Operation
Clock and Data Transitions:
The SDA pin is normally pulled high with an external device. Data on the SDA pin may change only
during SCL low time periods (see to Figure 1). Data changes during SCL high periods will indicate a
start or stop condition as defined below.
Start Condition:
A high-to-low transition of SDA with SCL high is a start condition which must precede any other
command (see to Figure 2).
Stop Condition:
A low-to-high transition of SDA with SCL high is a stop condition. After a read sequence, the stop command
will place the EEPROM in a standby power mode (see to Figure 2).
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