UPSD3212C, UPSD3212CV
Complex PLD (CPLD)
The CPLD can be used to implement system logic
functions, such as loadable counters and shift reg-
isters, system mailboxes, handshaking protocols,
state machines, and random logic. The CPLD can
also be used to generate External Chip Select
(ECS1-ECS2), routed to Port D.
■ AND Array capable of generating up to 137
product terms
■ Four I/O Ports.
Each of the blocks are described in the sections
that follow.
Although External Chip Select (ECS1-ECS2) can
be produced by any Output Macrocell (OMC),
these External Chip Select (ECS1-ECS2) on Port
D do not consume any Output Macrocells (OMC).
As shown in Figure 48, the CPLD has the following
blocks:
■ 20 Input Macrocells (IMC)
■ 16 Output Macrocells (OMC)
■ Macrocell Allocator
The Input Macrocells (IMC) and Output Macrocells
(OMC) are connected to the PSD MODULE inter-
nal data bus and can be directly accessed by the
MCU. This enables the MCU software to load data
into the Output Macrocells (OMC) or read data
from both the Input and Output Macrocells (IMC
and OMC).
This feature allows efficient implementation of sys-
tem logic and eliminates the need to connect the
data bus to the AND Array as required in most
standard PLD macrocell architectures.
■ Product Term Allocator
Figure 50. Macrocell and I/O Port
PRODUCT TERMS
FROM OTHER
MACROCELLS
MCU ADDRESS / DATA BUS
TO OTHER I/O PORTS
CPLD MACROCELLS
I/O PORTS
DATA
LOAD
LATCHED
ADDRESS OUT
PT PRESET
CONTROL
MCU DATA IN
MCU LOAD
PRODUCT TERM
ALLOCATOR
I/O PIN
DATA
D
Q
MUX
WR
UP TO 10
PRODUCT TERMS
MACROCELL
OUT TO
MCU
CPLD OUTPUT
POLARITY
SELECT
PR DI LD
D/T
SELECT
Q
PT
CPLD
OUTPUT
PDR
CLOCK
INPUT
D/T/JK FF
SELECT
COMB.
/REG
SELECT
GLOBAL
CLOCK
MACROCELL
CK
TO
I/O PORT
ALLOC.
CL
CLOCK
SELECT
Q
DIR
REG.
D
WR
PT CLEAR
(
)
PT OUTPUT ENABLE OE
MACROCELL FEEDBACK
I/O PORT INPUT
INPUT MACROCELLS
Q
Q
D
PT INPUT LATCH GATE/CLOCK
D
G
ALE
AI06602
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STMICROELECTRONICS [ ST ]
