SMC Networks AHB SRAM/NOR, PL241 manual SMC interface, APB slave interface, Format, Memory manager

Models: AHB SRAM/NOR PL241

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2.2.1SMC interface

Functional Overview

2.2.1SMC interface

The SMC interface processes the incoming AHB transfers and sends them to the command format block.

2.2.2APB slave interface

The SMC has 4KB of memory allocated to it.

The APB slave interface accesses the SMC registers to program the memory system configuration parameters and to provide status information. See Chapter 3 Programmer’s Model and APB slave interface operation on page 2-19for more information.

2.2.3Format

The format block receives memory accesses from the SMC interface and the memory manager. Read and write requests are arbitrated on a round robin basis. Requests from the manager have the highest priority. The format block also maps AHB memory transfers onto appropriate memory transfers and passes these to the memory interface through the command FIFO.

See Format block on page 2-19for more information.

2.2.4Memory manager

The memory manager tracks and controls the current state of smc_aclk domain logic. The block is responsible for:

updating timing registers and controlling direct commands issued to memory

controlling entry-to and exit-from low-power mode through the APB interface

the low-power interface.

See Memory manager operation on page 2-22for more information.

2.2.5Memory interface

The SRAM memory interface consists of command, read data and write data FIFOs, plus a control FSM. To support an EBI, the memory interface also contains an EBI FSM. This controls interaction with the EBI and prevents the memory interface FSM from issuing commands until it has been granted the external bus.

See Memory interface operation on page 2-27for more information.

ARM DDI 0389B

Copyright © 2006 ARM Limited. All rights reserved.

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SMC Networks AHB SRAM/NOR, PL241 manual SMC interface, APB slave interface, Format, Memory manager, Memory interface