AMD AMD-K6-2/400 User Guide - Page 143
M/IO# (Memory or I/O
View all AMD AMD-K6-2/400 manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 143 highlights
23542A/0-September 2000 Preliminary Information AMD-K6™-2E+ Embedded Processor Data Sheet 5.34 M/IO# (Memory or I/O) Pin Attribute Summary Output The processor drives M/IO# during a bus cycle to indicate whether it is addressing the memory or I/O space. If M/IO# = 1, the processor is addressing memory or a memory-mapped I/O port as the result of an instruction fetch or an instruction that loads or stores data. If M/IO# = 0, the processor is addressing an I/O port during the execution of an I/O instruction. In addition, M/IO# is used to define other bus cycles, including interrupt acknowledge and special cycles. See Table 23 and Table 24 on page 142 for more details. Driven and Floated M/IO# is driven off the same clock edge as ADS# and remains in the same state until the clock edge on which NA# or the last expected BRDY# of the cycle is sampled asserted. M/IO# is driven during memory cycles, I/O cycles, special bus cycles, and interrupt acknowledge cycles. M/IO# is floated off the clock edge on which BOFF# is sampled asserted and off the clock edge that the processor asserts HLDA in response to HOLD. Chapter 5 Signal Descriptions 121