MACH230-20 Ver la hoja de datos (PDF) - Lattice Semiconductor
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MACH230-20 Datasheet PDF : 29 Pages
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FUNCTIONAL DESCRIPTION
The MACH230 consists of eight PAL blocks connected
by a switch matrix. There are 64 I/O pins and 2
dedicated input pins feeding the switch matrix. These
signals are distributed to the four PAL blocks for efficient
design implementation. There are 4 clock pins that can
also be used as dedicated inputs.
The PAL Blocks
Each PAL block in the MACH230 (Figure 1) contains a
64-product-term logic array, a logic allocator, 8 output
macrocells, 8 buried macrocells, and 8 I/O cells. The
switch matrix feeds each PAL block with 26 inputs. This
makes the PAL block look effectively like an independ-
ent “PAL26V16” with 8 buried macrocells.
In addition to the logic product terms, two output enable
product terms, an asynchronous reset product term,
and an asynchronous preset product term are provided.
One of the two output enable product terms can be
chosen within each I/O cell in the PAL block. All flip-flops
within the PAL block are initialized together.
The Switch Matrix
The MACH230 switch matrix is fed by the inputs and
feedback signals from the PAL blocks. Each PAL block
provides 16 internal feedback signals and 8 I/O
feedback signals. The switch matrix distributes these
signals back to the PAL blocks in an efficient manner
that also provides for high performance. The design
software automatically configures the switch matrix
when fitting a design into the device.
The MACH230 places a restriction on buried macrocell
feedback only. Buried macrocell feedback from one
block can be used as an input only to that block or its
“sibling” block. Sibling blocks are illustrated in the block
diagram and in Table 1. Output macrocell feedback is
not restricted.
Table 1. Sibling Blocks
PAL Block
A
B
C
D
E
F
G
H
Sibling Block
H
G
F
E
D
C
B
A
The Product-Term Array
The MACH230 product-term array consists of 64
product terms for logic use, and 4 special-purpose
product terms. Two of the special-purpose product
terms provide programmable output enable, one
provides asynchronous reset, and one provides asyn-
chronous preset.
The Logic Allocator
The logic allocator in the MACH230 takes the 64 logic
product terms and allocates them to the 16 macrocells
as needed. Each macrocell can be driven by up to 16
product terms. The design software automatically
configures the logic allocator when fitting the design into
the device.
Table 2 illustrates which product term clusters are
available to each macrocell within a PAL block. Refer to
Figure 1 for cluster and macrocell numbers.
Table 2. Logic Allocation
Macrocell
Output
Buried
Available
Clusters
M0
C0, C1, C2
M1
C0, C1, C2, C3
M2
C1, C2, C3, C4
M3
C2, C3, C4, C5
M4
C3, C4, C5, C6
M5
C4, C5, C6, C7
M6
C5, C6, C7, C8
M7
C6, C7, C8, C9
M8
C7, C8, C9, C10
M9
C8, C9, C10, C11
M10
C9, C10, C11, C12
M11
C10, C11, C12, C13
M12
C11, C12, C13, C14
M13
C12, C13, C14, C15
M14
C13, C14, C15
M15
C14, C15
The Macrocell
The MACH230 has two types of macrocell: output and
buried. The output macrocells can be configured as
either registered, latched, or combinatorial, with pro-
grammable polarity. The macrocell provides internal
feedback whether configured with or without the flip-
flop. The registers can be configured as D-type or
T-type, allowing for product-term optimization.
The flip-flops can individually select one of four clock/
gate pins, which are also available as data inputs. The
registers are clocked on the LOW-to-HIGH transition of
the clock signal. The latch holds its data when the gate
input is HIGH, and is transparent when the gate input is
LOW. The flip-flops can also be asynchronously initial-
ized with the common asynchronous reset and preset
product terms.
The buried macrocells are the same as the output
macrocells if they are used for generating logic. In that
case, the only thing that distinguishes them from the
output macrocells is the fact that there is no I/O cell
connection, and the signal is only used internally. The
buried macrocell can also be configured as an input
register or latch.
The I/O Cell
The I/O cell in the MACH230 consists of a three-state
output buffer. The three-state buffer can be configured
in one of three ways: always enabled, always disabled,
or controlled by a product term. If product term control is
chosen, one of two product terms may be used to
provide the control. The two product terms that are
available are common to all I/O cells in a PAL block.
These choices make it possible to use the macrocell as
an output, an input, a bidirectional pin, or a three-state
output for use in driving a bus.
6
MACH230-10/15/20
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