ST & T UPSD3212C - Manual (Page 109)

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uPSD3212A, 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.
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
54 , the CPLD has the following
blocks:
■ 20 Input Macrocells (IMC)
■ 16 Output Macrocells (OMC)
■ Macrocell Allocator
■ Product Term Allocator
■ 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.
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.
Figure 56. Macrocell and I/O Port
I/O PORTS CPLD MACROCELLS
INPUT MACROCELLS
LATCHED
ADDRESS OUT
MUX
MUX
MUX
MUX
MUX
D
D
Q
Q
Q
G
D
Q D
WR
WR
PDR
DATA
PRODUCT TERM
ALLOCATOR
DIR
REG.
SELECT
INPUT
PRODUCT TERMS
FROM OTHER
MACROCELLS
POLARITY
SELECT
UP TO 10
PRODUCT TERMS
CLOCK
SELECT
PR DI LD
D/T
CK
CL
Q
D/T/JK FF
SELECT
PT CLEAR
PT
CLOCK
GLOBAL
CLOCK
PT OUTPUT ENABLE (OE)
MACROCELL FEEDBACK
I/O PORT INPUT
ALE
PT INPUT LATCH GATE/CLOCK
MCU LOAD
PT PRESET
MCU DATA IN
COMB.
/REG
SELECT
MACROCELL
TO
I/O PORT
ALLOC.
CPLD
OUTPUT
TO OTHER I/O PORTS
PLD INPUT BUS
PLD INPUT BUS
MCU ADDRESS / DATA BUS
MACROCELL
OUT TO
MCU
DATA
LOAD
CONTROL
AND ARRAY
CPLD OUTPUT
I/O PIN
AI06602