psd813f1a-90ut STMicroelectronics, psd813f1a-90ut Datasheet - Page 36

• Manufacturer Part Number: psd813f1a-90ut
• Description: Flash In-system Programmable Isp Peripherals For 8-bit Mcus
• Manufacturer: STMicroelectronics

Preliminary
The
PSD913F1
Functional
Blocks
(cont.)
Each of the two PLDs has unique characteristics suited for its applications They are
described in the following sections.
9.2.1 Decode PLD (DPLD)
The DPLD, shown in Figure 12, is used for decoding the address for internal PSD
components. The DPLD can generate the following chip selects:
Inputs to the DPLD chip selects may include address inputs, Page Register inputs and
other user defined external inputs from Ports A, B, C or D.
9.2.2 General Purpose PLD (GPLD)
The General Purpose PLD implements user defined system combinatorial logic function
or chip selects for external devices. Figure 13 shows how the GPLD is connected to the I/O
Ports. The GPLD has 19 outputs and each are routed to a port pin. The port pin can also be
configured as input tot eh GPLD. When it is not used as GPLD output or input, the pin can
be configured to perform other I/O functions.
The GPLD outputs are identical except in the number of available product terms for logic
implementation. Select the pin that can best meet the product term requirement of your
logic function or chip selects. The outputs can be configured as active high or low outputs.
Table 14 shows the number of product terms that are assigned to the PLD outputs on the
I/O Ports. When PSD913F1 is connected to a MCU with non-multiplexed bus, Port A will be
configured as the Data Port and the GPLD outputs will not be available.
Table 14. GPLD Output Product Term
•
•
•
•
GPLD Output on Port Pin
8 sector selects for the main Flash memory (three product terms each)
4 sector selects for the Secondary Flash memory (three product terms each)
1 internal SRAM select (two product terms)
1 internal CSIOP select (select PSD registers, one product term)
Port D, pins PD0-2
Port B, pins PB0-3
Port B, pins PB4-7
Port A, pins PA0-3
Port A, pins PA4-7
Number of Product Terms
3
9
4
7
1
PSD913F1
35