VSSF and VSSS Ground. VSSF and VSSS are the
ground reference for all voltage measurements in
the Flash and SRAM chips, respectively.
Note: Each device in a system should have VD-
DF, VDDQF and VPPF decoupled with a 0.1µF ca-
pacitor close to the pin. See Figure 9, AC
Measurement Load Circuit. The PCB trace
widths should be sufficient to carry the re-
quired VPPF program and erase currents.
The Flash and SRAM components have separate
power supplies and grounds and are distinguished
by three chip enable inputs: EF for the Flash mem-
ory and E1S and E2S for the SRAM.
Recommended operating conditions do not allow
both the Flash and the SRAM to be in active mode
at the same time. The most common example is
simultaneous read operations on the Flash and
the SRAM which would result in a data bus con-
tention. Therefore it is recommended to put the
SRAM in the high impedance state when reading
the Flash and vice versa (see Table 2 Main Oper-
ation Modes for details).
Figure 4. Functional Block Diagram
16 Mbit (x16)
2 Mbit (x16)