MOTOROLA M68040 USER’S MANUAL 7- 71
DLE MODE DATA BUS TIMING
NORMAL DATA BUS TIMING
CASE 1 CASE 2
Figure 7-48. DLE versus Normal Data Read Timing
If DLE is negated and meets setup time specification #35 to the rising edge of BCLK
when the bus read is terminated, latch A is transparent, and the read data must meet
setup and hold time specifications #36 and #37 to the rising edge of BCLK. Read timing
is similar to normal timing for this case.
If DLE is asserted, the data bus levels are latched and held internally. D31–D0 must
meet setup and hold time specifications #32 and #33 to the falling edge of DLE, and can
transition to a new level once DLE is asserted. D31–D0 must still meet setup time
specification #36 to BCLK, but not hold time specification #37, since the data is
internally held valid as long as DLE remains asserted low.