PSD4XX Datasheet, PDF (13/123 Pages) STMicroelectronics – Low Cost Field Programmable Microcontroller Peripherals

PSD4XX Family
9.0
The PSD4XX
Architecture
PSD4XX consists of five major functional blocks:
t ZPLD Blocks
t Bus Interface
t I/O Ports
t Memory Block
t Power Management Unit
The functions of each block are described in the following sections. Many of the blocks
perform multiple functions, and are user configurable. The chip configurations are specified
by the user in the PSDsoft Development Software. Other configurations are specified by
setting up the appropriate bits in the configuration registers during run time.
9.1 The ZPLD Block
The PSD4XX series devices provide two ZPLD configurations. The ZPLD in the
PSD4XXA1 devices has 8 registered macrocells, 8 combinatorial macrocells, and up to 113
product terms.
The PSD4XXA2 has a full function ZPLD with 24 registered macrocells and up to 126
product terms.
9.1.1 The PSD4XXA1 ZPLD Block
Key Features
t 2 Embedded ZPLD devices
t 8 registered and 8 combinatorial macrocells
t Combinatorial/registered outputs
t Maximum 113 product terms
t Programmable output polarity
t User configured register clear/preset
t User configured register clock input
t 37 Inputs
t Accessible via 16 I/O pins
t Power Saving Mode
t UV-Erasable
General Description
The ZPLD block has 2 embedded PLD devices:
t DPLD
The Address Decoding PLD, generating select signals to internal I/O or memory blocks.
t GPLD
The General Purpose PLD provides 8 registered and combinatorial programmable
macrocells for general or complex logic implementation; dedicated to user application.
Figure 4 shows the architecture of the ZPLD. The PLD devices all share the same input
bus. The true or complement of the 37 input signals are fed to the programmable
AND-ARRAY. Names and sources of the input signals are shown in Table 3. The PB
signals, depending on user configuration, can either be macrocell feedbacks or inputs from
Port B.
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