UPSD3234AV-24U1T STMicroelectronics, UPSD3234AV-24U1T Datasheet - Page 117

• Manufacturer Part Number: UPSD3234AV-24U1T
• Description: Flash Programmable System Devices with 8032 Microcontroller Core and 64Kbit SRAM
• Manufacturer: STMicroelectronics

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Product Term Allocator
The CPLD has a Product Term Allocator. PSDsoft
uses the Product Term Allocator to borrow and
place product terms from one macrocell to anoth-
er. The following list summarizes how product
terms are allocated:
–
–
–
Each macrocell may only borrow product terms
from certain other macrocells. Product terms al-
ready in use by one macrocell are not available for
another macrocell.
If an equation requires more product terms than
are available to it, then “external” product terms
are required, which consume other Output Macro-
cells (OMC). If external product terms are used,
extra delay is added for the equation that required
the extra product terms.
Figure 61. CPLD Output Macrocell
McellAB0-McellAB7 all have three native
product terms and may borrow up to six more
McellBC0-McellBC3 all have four native
product terms and may borrow up to five more
McellBC4-McellBC7 all have four native
product terms and may borrow up to six more.
ALLOCATOR
PT CLK
CLKIN
PT
PT
MACROCELL CS
PT
PT
MASK
REG.
FEEDBACK ( .FB )
POLARITY
RD
WR
SELECT
PORT INPUT
CLEAR ( .RE )
ENABLE (.OE)
PRESET(.PR)
MUX
uPSD3234A, uPSD3234BV, uPSD3233B, uPSD3233BV
IN
LD
DIN
CLR
PROGRAMMABLE
FF ( D/ T/JK /SR )
PR
This is called product term expansion. PSDsoft
Express performs this expansion as needed.
Loading and Reading the Output Macrocells
(OMC). The Output Macrocells (OMC) block oc-
cupies a memory location in the MCU address
space, as defined by the CSIOP block (see the
section
MODULE), page
16 Output Macrocells (OMC) can be loaded from
the data bus by a MCU. Loading the Output Mac-
rocells (OMC) with data from the MCU takes prior-
ity over internal functions. As such, the preset,
clear, and clock inputs to the flip-flop can be over-
ridden by the MCU. The ability to load the flip-flops
and read them back is useful in such applications
as loadable counters and shift registers, mailbox-
es, and handshaking protocols.
Data can be loaded to the Output Macrocells
(OMC) on the trailing edge of WRITE Strobe (WR,
edge loading) or during the time that WRITE
Strobe (WR) is active (level loading). The method
of loading is specified in PSDsoft Express Config-
uration.
Q
COMB/REG
SELECT
MUX
MCU DATA BUS
entitled
119). The flip-flops in each of the
MACROCELL
ALLOCATOR
DIRECTION
REGISTER
D [ 7:0 ]
I/O
MACROCELL
PORTS
PORT
DRIVER
INPUT
117/170
AI06617
(PSD
I/O PIN