The fundamental architecture of MACH 4 devices (Figure 1) consists of multiple optimized PAL®
blocks interconnected by a central switch matrix. The central switch matrix allows
communication between PAL blocks and routes inputs to the PAL blocks. Together, the PAL
blocks and central switch matrix allow the logic designer to create large designs in a single
device instead of having to use multiple devices.
The key to being able to make effective use of these devices lies in the interconnect schemes.
In MACH 4 architecture, the macrocells have been decoupled from the product terms through
the logic allocator, and the I/O pins have been decoupled from the macrocells due to the output
switch matrix. In addition, more input routing options are provided by the input switch matrix.
These resources provide the ﬂexibility needed to ﬁt designs efﬁciently.
Logic 16 Output/ 16
Figure 1. MACH 4 Block Diagram and PAL Block Structure
1. 16 for MACH 4 and MACH 4A devices with 1:1 macrocell-I/O cell ratio (see next page).
2. Block clocks do not go to I/O cells in M4(LV)-32/32 or M4A(3,5)-32/32.
3. M4(LV)-192/96, M4(LV)-256/128, M4A(3,5)-192, M4A(3,5)-256, M4A3-384, and M4A3-512 have dedicated clock pins which
cannot be used as inputs and do not connect to the central switch matrix.
MACH 4 Family