AMD-K6-2E Datasheet, PDF (113/332 Pages) Advanced Micro Devices – AMD-K6™-2E Embedded Processor

22529B/0—January 2000
Preliminary Information
AMD-K6™-2E Processor Data Sheet
5.12
BRDY# (Burst Ready)
Pin Attribute
Input, Internal Pullup
Pin Location
Summary
X-04
BRDY# is asserted to the processor by system logic to indicate
either that the data bus is being driven with valid data during a
read cycle or that the data bus has been latched during a write
cycle. If necessary, the system logic can insert bus cycle wait
states by negating BRDY# until it is ready to continue the data
transfer. BRDY # is also used to indicate the completion of
special bus cycles.
Sampled
BRDY# is sampled every clock edge within a bus cycle starting
with the clock edge after the clock edge that negates ADS #.
BRDY# is ignored while the bus is idle. The processor samples
the following inputs on the clock edge on which BRDY # is
sampled asserted: D[63:0], DP[7:0], and KEN # during read
cycles, EWBE # during write cycles (if not masked off), and
WB/WT # during read and write cycles. If NA # is sampled
asserted prior to BRDY#, then KEN# and WB/WT# are sampled
on the clock edge on which NA# is sampled asserted.
The number of times the processor expects to sample BRDY #
asserted depends on the type of bus cycle, as follows:
s One time for a single-transfer cycle, a special bus cycle, or
each of two cycles in an interrupt acknowledge sequence
s Four times for a burst cycle (once for each data transfer)
BRDY # can be held asserted for four consecutive clocks
throughout the four transfers of the burst, or it can be negated
to insert wait states.
Chapter 5
Signal Descriptions
95