Input Cells (INC)
Input cells (INC) are included on dedicated input pins. The
block diagram of the INC is shown in Figure 6. Each INC
consists of a multiplexer and a register/transparent latch,
which can be clocked from various sources selected by the
global cell (see Figure 7). The register is rising edge
clocked. The latch is transparent when the clock is high
and latched on the clock’s falling edge. The register/ latch
can also be bypassed for a non-registered input.
Global Cells
The global cells, shown in Figure 10, are used to direct global
clock signals and/or control terms to the LCCs, IOCs and
INCs. The global cells allow a clock to be selected from the
CLK1 pin, CLK2 pin, or a product term from the logic array
(PCLK). They also provide polarity control for INC and IOC
clocks enabling rising or falling clock edges for input
registers/latches. Note that each individual LCC clock has its
own polarity control. The global cell for LCCs includes sum-
of-products control terms for global reset and preset, and a
fast product term control for LCC register-type, used to save
product terms for loadable counters and state machines (see
Figure 11). The PA7572 provides two global cells that divide
the LCC and IOCs into groups, A and B. Half of the LCCs and
IOCs use global cell A, half use global cell B. This means that
two high-speed global clocks can be used among the LCCs.
CLK1
CLK2
M UX
PCLK
INC Clocks
I/O Cell (IOC)
All PEEL™ Arrays have I/O cells (IOC) as shown above in
Figure 6. Inputs to the IOCs can be fed from any of the
LCCs in the array. Each IOC consists of routing and control
multiplexers, an input register/transparent latch, a three-
state buffer and an output polarity control. The register/
latch can be clocked from a variety of sources determined
by the global cell. It can also be bypassed for a non-
registered input. The PA7572 allows the use of SUM-D as
a feedback to the array when the I/O pin is a dedicated
output. This allows for additional buried registers and logic
paths. (See Figure 8 and Figure 9).
G lobal Cell: INC
Group A & B
CLK1
CLK2
Q D
M UX
LCC Clocks
M UX
PCLK
IOC Clocks
Input with optional
register/latch
I/O
Reg-Type
Preset
LCC Reg-Type
LCC Presets
LCC Resets
I/O with
independent
output enable
A
B
C
D
D Q
Reset
G lobal Cell: LCC & IO C
08-15-010A
1
2
OE
08-15-008A
Figure 10. Global Cells
Reg-Type from Glob al Cell
Figure 8. LCC & IOC With Two Outputs
D
Q D
Register Ty pe Change Feature
P
Q
Global Cell can dynam ically change user-
selected LCC registers from D to T or from D
to JK. This saves product term s for loadable
counters or state m achines. Use as D register
to load, use as T or JK to count. Tim ing
allow s dynam ic operation.
Buried register or
logic paths
O utput
R
A
B
C
D
D Q
1
T
2
3
P
Example:
Product term s for 10 bit loadable binary counter
Q
D uses 57 product term s (47 count, 10 load)
T uses 30 product term s (10 count, 20 load)
D/T uses 20 product term s (10 count, 10 load)
08-15-011 A
R
08-15-009A
Figure 9. LCC & IOC With Three Outputs
Anachip Corp.
www.anachip.com.tw
4/10
Figure 11. Register Type Change Feature
Rev. 1.0 Dec 16, 2004
ANACHIP [ ANACHIP CORP ]
