MACHLV210 Lattice Semiconductor Corp., MACHLV210 Datasheet - Page 6

• Manufacturer Part Number: MACHLV210
• Description: High Density Ee Cmos Programmable Logic
• Manufacturer: Lattice Semiconductor Corp.

FUNCTIONAL DESCRIPTION
The MACHLV210 consists of four PAL blocks
connected by a switch matrix. There are 32 I/O pins and
4 dedicated input pins feeding the switch matrix. These
signals are distributed to the four PAL blocks for efficient
design implementation. There are two clock pins that
can also be used as dedicated inputs.
The MACHLV210 inputs and I/O pins have advanced
pull-up/pull-down resistors that enable the inputs to be
pulled to the last driven state. While it is always a good
design practice to tie unused pins high or low, the
MACHLV210 pull-up/pull-down resistors provide design
security and stability in the event that unused pins are
left disconnected.
The PAL Blocks
Each PAL block in the MACHLV210 (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 22 inputs. This
makes the PAL block look effectively like an
independent “PAL22V16” 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 MACHLV210 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 feed-
back 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 Product-term Array
The MACHLV210 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
asynchronous preset.
The Logic Allocator
The logic allocator in the MACHLV210 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 1 illustrates which product term clusters are avail-
able to each macrocell within a PAL block. Refer to
Figure 1 for cluster and macrocell numbers.
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MACHLV210-12/15/20
The Macrocell
The MACHLV210 has two types of macrocell: output
and buried. The output macrocells can be configured as
either registered, latched, or combinatorial, with
programmable 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 two 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 MACHLV210 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.
Output
M
M
M
M
M
M
M
M
10
12
14
0
2
4
6
8
Macrocell
Table 1. Logic Allocation
Buried
M
M
M
M
M
M
M
M
11
13
15
1
3
5
7
9
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
0
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
, C
, C
, C
, C
, C
, C
, C
, C
, C
, C
, C
, C
, C
, C
, C
, C
Available
Clusters
1
1
2
3
4
5
6
7
8
9
10
, C
, C
, C
, C
, C
, C
, C
, C
, C
, C
11
12
13
14
15
, C
, C
, C
, C
, C
2
2
3
4
5
6
7
8
9
10
, C
, C
, C
, C
, C
, C
, C
, C
11
, C
12
13
14
15
, C
, C
, C
, C
3
4
5
6
7
8
9
10
11
12
13
14
15