AT40KAL Ver la hoja de datos (PDF) - Atmel Corporation
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AT40KAL Datasheet PDF : 38 Pages
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The Busing Network
Figure 3 on page 7 depicts one of five identical busing planes. Each plane has three bus
resources: a local-bus resource (the middle bus) and two express-bus (both sides)
resources. Bus resources are connected via repeaters. Each repeater has connections
to two adjacent local-bus segments and two express-bus segments. Each local-bus
segment spans four cells and connects to consecutive repeaters. Each express-bus
segment spans eight cells and “leapfrogs” or bypasses a repeater. Repeaters regener-
ate signals and can connect any bus to any other bus (all pathways are legal) on the
same plane. Although not shown, a local bus can bypass a repeater via a programma-
ble pass gate allowing long on-chip tri-state buses to be created. Local/Local turns are
implemented through pass gates in the cell-bus interface (see following page).
Express/Express turns are implemented through separate pass gates distributed
throughout the array.
Some of the bus resource on the AT40KAL is used as a dual-function resource. Table 2
shows which buses are used in a dual-function mode and which bus plane is used. The
AT40KAL software tools are designed to accommodate dual-function buses in an effi-
cient manner.
Table 2. Dual-function Buses
Function
Type
Cell Output Enable
Local
RAM Output Enable
Express
RAM Write Enable
Express
RAM Address
Express
RAM Data In
RAM Data Out
Clocking
Set/Reset
Local
Local
Express
Express
Plane(s)
5
2
1
1-5
1
2
4
5
Direction Comments
Horizontal and
Vertical
Vertical
Bus full length at array edge
Bus in first column to left of RAM block
Vertical
Bus full length at array edge
Bus in first column to left of RAM block
Vertical
Buses full length at array edge
Buses in second column to left of RAM block
Horizontal
Horizontal
Vertical
Bus half length at array edge
Vertical
Bus half length at array edge
6 AT40KAL
4263B–AERO–06/03
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