M34E04B Datasheet, PDF (8/35 Pages) STMicroelectronics – 4-Kbit Serial Presence Detect EEPROM compatible

Signal description
2
Signal description
M34E04B
2.1
Serial clock (SCL)
The signal applied on this input is used to strobe the data available on SDA(in) and to output
the data on SDA(out).
If SCL is driven low for tTIMEOUT (see Table 13) or longer, the M34E04B is set back in
Standby mode, ready to receive a new START condition.
2.2
Serial data (SDA)
SDA is an input/output used to transfer data in or out of the device. SDA(out) is an open
drain output that may be wire-OR’ed with other open drain or open collector signals on the
bus. A pull-up resistor must be connected from Serial Data (SDA) to V_CC. (Figure 12
indicates how the value of the pull-up resistor can be calculated).
2.3
Slave address (SA2, SA1, SA0)
(SA2,SA1,SA0) input signals are used to set the value that is to be looked for on the three
least significant bits (b3, b2, b1) of the 7-bit Device Type Identifier Code (DTIC, see
Table 2). These inputs must be tied to V_CC or V_SS, as shown in Figure 3. When not
connected (left floating), these inputs are read as low (0).
The SA0 input is used to detect the V_HV voltage, when decoding an SWP or CWP
instruction.
Figure 3. Device select code
9&&
9&&
0(%
6$ _L
0(%
6$ _L
966
966
D^ǀϯϴϰϱϭsϭ
2.4
2.4.1
Supply voltage (V_CC)
Operating supply voltage V_CC
Prior to selecting the memory and issuing instructions to it, a valid and stable V_CC voltage
within the specified [V_CC(min), V_CC(max)] range must be applied (see Table 8). In order to
secure a stable DC supply voltage, it is recommended to decouple the V_CC line with a
suitable capacitor (usually of the order of 10 nF to 100 nF) close to the V_CC/V_SS package
pins.
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