Table 7. AC Electrical Characteristics – Read and Write Cycles(1) (Continued)
CC = 5.0 VDC 10%; GND = 0 VDC; Tc = -55°C/+125°C or Tc = -40°C/+85°C (see Figure 7, Figure 8, Figure 9)
V
16.67 MHz 20 MHz 25 MHz 33.33 MHz
N°
Parameter
Min
Max
Min
Max
Min
Max
Min
Max
Unit
START false to DSACK0 and DSACK1
high impedance(8)
22
70
55
55
40
ns
START true to clock high (synchronous
read)(3)(8)
23
24
25
26
27
0
0
0
0
ns
ns
Clock low to data-out valid synchronous
read)(3)
105
80
60
45
START true to data-out valid (synchronous
read)(3)(8)
0
1.5
105+
2.5
80 +
2.5
60+
2.5
45-
2.5
ns
Clks
1.5
1.5
1.5
1.5
1.5
1.5
Clock low to DSACK0 and DSACK1
asserted (synchronous read(3)
75
55
45
30
ns
START true to DSACK0 and DSACK1
asserted (synchronous read) (3)(8)
75+
2.5
55+
2.5
45+
2.5
30-
2.5
ns
Clks
1.5
Notes: 1. Timing measurements are referenced to and from a low voltage of 0.8V and a high voltage of 2.0V, unless otherwise noted.
The voltage swing through this range should start outside, and pass through, the range such that the rise or fall will be linear
between 0.8V and 2.0V.
2. These specifications only apply if the TS68882 has completed all internal operations initiated by the termination of the previ-
ous bus cycle when DS was negated.
3. Synchronous read cycles occur only when the save or response CIR locations are read.
4. This specification only applies to systems in which back-to-back accesses (read-write or write-write) of the operand CIR can
occur. When the TS68882 is used as a co-processor to the TS68020/68030, this can occur when the addressing mode is
immediate.
5. If the SIZE pin is not strapped to either VCC or GND, it must have the same setup times as do addresses.
6. If the SIZE pin is not strapped to either VCC or GND, it must have the same hold times as do addresses.
7. This number is reduced to 5 nanoseconds if DSACK0 and DSACK1 have equal loads.
8. START is not an external signal; rather, it is the logical condition that indicates the start of an access. The logical equation for
this condition is START = CS + AS + (R/W · DS).
9. If a subsequent access is not a FPCP access, CS must be negated before the assertion of AS and/or DS on the non-FPCP
access. These specifications replace the old specifications 8 and 8A (the old specifications implied that in all cases, transi-
tions in CS must not occur simultaneously with transitions of AS or DS. This is not a requirement of the TS68882).
12
TS68882
2119A–HIREL–04/02
ATMEL [ ATMEL ]
