PSD935G3V-C-15UI 데이터 시트보기 (PDF) - STMicroelectronics

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PSD935G3V-C-15UI

Configurable Memory System on a Chip for 8-Bit Microcontrollers

STMicroelectronics 

PSD935G2

The

PSD935G2

Functional

Blocks

(cont.)

PSD9XX Family

9.4.2.3 Address Out Mode

For microcontrollers with a multiplexed address/data bus, Address Out Mode can be used

to drive latched addresses onto the port pins. These port pins can, in turn, drive external

devices. Either the output enable or the corresponding bits of both the Direction Register

and Control Register must be set to a ‘1’ for pins to use Address Out Mode. This must be

done by the MCU at run-time. See Table 18 for the address output pin assignments on

Ports E, F and F for various MCUs.

Note: Do not drive address lines with Address Out Mode to an external memory device if

it is intended for the MCU to boot from the external device. The MCU must first boot from

PSD memory so the Direction and Control register bits can be set.

Table 18. I/O Port Latched Address Output Assignments

MCU

Port E (3:0) Port E (7:4) Port F (3:0) Port F (7:4) Port G (3:0) Port G (7:4)

80C51XA

80C251

(Page Mode)

All Other

Eight-Bit

Multiplexed

8-Bit

Non-Mux

Bus

N/A*

N/A

Addr (3:0)

N/A

Addr (7:4)

N/A

Addr (7:4)

N/A

N/A*

N/A

Addr (3:0)

N/A

Addr (7:4) Addr (11:8)

N/A

N/A

Addr (11:8) Addr (15:12)

Addr (7:4) Addr (3:0) Addr (7:4)

N/A

Addr (3:0) Addr (7:4)

9.4.2.4 Address In Mode

For microcontrollers that have more than 16 address lines, the higher addresses can be

connected to Ports A, B, C, D or F and are routed as inputs to the PLDs. The address

input can be latched by the address strobe (ALE/AS). Any input that is included in the

DPLD equations for the Main Flash, Boot Flash, or SRAM is considered to be an address

input.

9.4.2.5 Data Port Mode

Port F can be used as a data bus port for a microcontroller with a non-multiplexed

address/data bus. The Data Port is connected to the data bus of the microcontroller. The

general I/O functions are disabled in Port F if the port is configured as Data Port. Data Port

Mode is automatically configured in PSDsoft when a non-multiplexed bus MCU is selected.

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