Figure 8. Mode 1 Read Cycle
MODE
DATA
Data
LOW ADDRESS
Addr
CS
Clock
RD
Timing
In this paragraph are provided the AC specification for the AT7908E interface signals in
both operational modes.
AC Specification for 8 bit
Multiplexed Mode (mode =0)
Conditions: VCC = 5V ±10%, VSS = 0V, Ta = -55°C to +125 °C, Cl = 80 pF ,
Tclk = 100 ns
Symbol
tAVLL
Parameter
Min
Max
Note
Address valid to ALE low
Address Hold after ALE low
ALE HIGH Time
4 ns
Mode 0
tLLAX
4 ns
Mode 0
tLHLL (*)
tLLRL (*)
tCHRL
Tclk
Mode 0
ALE low to RD low
2 Tclk
100 ns
3 Tclk
10 ns
3 Tclk
Tclk
Mode 0
CS high to RD low
Mode 0
tDVWH] (*)
tWHQX (*)
tWLWH (*)
tWHLH (*)
tWS
Input Data valid to WR High
Input data hold after WR high
WR pulse width
Mode 0, mode 1
Mode 0, mode 1
Mode 0, mode 1
WR high to next ALE high
WR setup time before clock
WR hold time after clock
RD pulse width
-3 ns
7 ns
Mode 0, mode 1
Mode 0, mode 1
Mode 0, mode 1
Mode 0, mode 1
Mode 0, mode 1
tWH (*)
tRLRH (*)
tRLDV (*)
tRHDZ (*)
3 Tclk
6 ns
RD low to data valid
Data float after RD High
82 ns
20 ns
4 ns
Note:
1. Guaranteed, not tested.
20
AT7908E
4268D–AERO–11/09
ATMEL [ ATMEL ]
