SMC Networks AHB SRAM/NOR, PL241 manual Interrupts operation, Memory interface operation

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Functional Overview

2.4.7Interrupts operation

The next read to any chip select on the appropriate memory interface clears the interrupt.

The interrupt outputs are generated through a combinational path from the relevant input pin. This enables you to place the SMC in Low-power state, and to stop the clocks while waiting for an interrupt.

When interrupts are disabled, a synchronized version of the interrupt input is still readable through the APB interface.

2.4.8Memory interface operation

The memory interface issues commands to the memory from the command FIFO, and controls the cycle timings of these commands. A new command is only issued when the previous command is complete and any turn-around times have been met. Additionally, a read command is not issued unless there is space for all the impending data in the read data FIFO.

Note

You must not set the rd_bl parameter in the smc_opmode Register to a value greater than the read data FIFO depth of four.

If enabled, the EBI can prevent commands being issued when the SMC is not granted the external bus.

Figure 2-14 on page 2-29to Figure 2-23 on page 2-38show the timing parameters.

They are divided into SRAM timing tables and diagrams.

The internal signal read_data is included in the read transfer waveforms to indicate the clock edge on which data is registered by the SMC.

SRAM timing tables and diagrams

All address, control, and write data outputs of the SMC are registered on the rising edge of smc_mclk0n, equivalent to the falling edge of smc_mclk0, for both synchronous and asynchronous accesses. The clock output to memory, smc_clk_out, is driven directly by smc_mclk0, but gated to prevent toggling during asynchronous accesses, or when no transfers are occurring.

ARM DDI 0389B

Copyright © 2006 ARM Limited. All rights reserved.

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Contents PrimeCell AHB SRAM/NOR Memory Controller PL241 Copyright 2006 ARM Limited. All rights reserved PrimeCell AHB SRAM/NOR Memory Controller PL241Technical Reference Manual Contents Chapter Programmer’s Model for Test List of Tables List of Tables List of Figures Figure A-1 AHB MC PL241 grouping of signals Feedback on PrefaceIntended audience Using this manualAbout this manual Product revision statusBold ConventionsTypographical Signals Timing diagramsARM publications NumberingFurther reading Feedback on this manual FeedbackFeedback on this product Introduction SMC on About the AHB MCThis section describes AHB to APB bridge AHB interfaceClock domains Low-power interfaces3 SMC Intel W18 series NOR FLASH, for example 28f128W18td Supported devicesIntroduction Copyright 2006 ARM Limited. All rights reserved Functional Overview This section is divided into Functional descriptionStatic memory clock domain Smcmreset0nLow-power interface AHB clock domainInterrupts on SMCMain blocks of the SMC are Format onMemory manager SMC interfaceAPB slave interface FormatInterrupts Pad interfaceAHB fixed burst types Functional operationAHB interface operation Broken bursts Bufferable bit of the Hprot signalUndefined length Incr bursts Locked transfers AHB response signalsRead after write hazard detection buffer AHB to APB bridge operation Big-endian 32-bit modeRemoval of AHB error response logic Registered HwdataAhbc memory map Clock domain operationStatic memory clocking options Low-power interface operationStatic memory clocking options 1lists the static memory clocking optionsAn active output Domaincactive Where Domain is ahb or smcAccepting requests SMC states are as follows SMC functional operationOperating states Clocking Clocking and resetsResets Smcagtm0sync Miscellaneous signalsSmcuserconfig70 Smcuserstatus70Hazard handling APB slave interface operationFormat block Sram memory accesses Memory burst length Memory manager operation Low-power operationChip configuration registers 11 Chip configuration registers Software mechanism Direct commandsDevice pin mechanism 12 Device pin mechanism 13 Software mechanism Memory interface operation Sram timing tables and diagramsInterrupts operation Asynchronous read Sram cycles register settings Asynchronous read opmode chip register settings14 Asynchronous read 4and -5list the smcopmode00-3 and Sram Register settingsAsynchronous write Sram cycles register settings 6and -7list the smcopmode00-3 and Sram Register settingsAsynchronous write opmode chip register settings 10 Page read opmode chip register settings 8and -9list the smcopmode00-3 and Sram Register settings10and -11list the smcopmode00-3 and Sram Register settings 13 Synchronous burst read Sram cycles register settings 12and -13list the smcopmode00-3 and Sram Register settings12 Synchronous burst read opmode chip register settings 19 Synchronous burst read 20 Synchronous burst read in multiplexed-mode 14and -15list the smcopmode00-3 and Sram Register settings17 Synchronous burst write Sram cycles register settings 16and -17list the smcopmode00-3 and Sram Register settings16 Synchronous burst write opmode chip register settings 22 Synchronous burst write in multiplexed-mode 18and -19list the smcopmode00-3 and Sram Register settingsB0100 B0110 B001 20and -21list the smcopmode00-3 and Sram Register settingsTCEOE is only required if wait is asserted when oen goes LOW TWC = ARM DDI 0389B Programmer’s Model About the programmer’s model Register summary 2shows the SMC configuration register map1lists the SMC Registers Name Base offset Type Reset value DescriptionRegister summary 2lists the register bit assignments Register descriptionsThis section describes the SMC registers SMC Memory Controller Status Register atBits Name Function SMC Memory Interface Configuration Register at3lists the register bit assignments Smcmemccfgset Register bit assignments SMC Set Configuration Register atSmcmemccfgclr Register bit assignments Bits Name Function SMC Clear Configuration Register at 0x100C4lists the register bit assignments 5lists the register bit assignmentsSmcdirectcmd Register bit assignments SMC Direct Command Register at6lists the register bit assignments Lists the register bit assignments SMC Set Cycles Register at12 smcsetopmode Register bit assignments SMC Set Opmode Register at8lists the register bit assignments Memory width mw field Smcsetopmode Register bit assignmentsSmcrefreshperiod0 Register bit assignments SMC Refresh Period 0 Register atSMC Sram Cycles Registers 0-3 at 0x1100, 0x1120, 0x1140 SMC Opmode Registers 0-3 at 0x1104, 0x1124, 0x1144 10lists the register bit assignments11lists the register bit assignments 12 smcuserstatus Register bit assignments SMC User Status Register at12lists the register bit assignments 11 smcopmode Register bit assignmentsBits Name Description SMC User Configuration Register at13 smcuserconfig Register bit assignments 13 lists the register bit assignments15 smcperiphid0 Register bit assignments Bits Name Function Following section describe the smcperiphid RegistersSMC Peripheral Identification Register 17 smcperiphid2 Register bit assignments Bits Name Function 16 smcperiphid1 Register bit assignments Bits Name Function19shows the register bit assignments SMC PrimeCell Identification Registers 0-3 at 0x1FF0-0x1FFC20 smcpcellid0 Register bit assignments Bits Name Function These registers cannot be read in the Reset stateFollowing sections describe the smcpcellid Registers SMC PrimeCell Identification Register23 smcpcellid3 Register bit assignments Bits Name Function 22 smcpcellid2 Register bit assignments Bits Name FunctionProgrammer’s Model for Test Lists the SMC integration test registers Test registers are provided for integration testingSMC Integration Configuration Register at 0x1E00 SMC integration test registersSmcintinputs Register bit assignments Bits Name Function Integration Inputs Register at 0x1E04State Integration Outputs Register at 0x1E08Device Driver Requirements Memory initialization SMC and memory initialization sheet 1 SMC and memory initialization sheet 2 SMC and memory initialization sheet 3 Where = denotes the appropriate chip selectARM DDI 0389B Signal Descriptions Where Ahbc = AHB Configuration signals About the signals listName Type Source Description Destination Clocks and resetsTable A-1lists the clock and reset signals Table A-2 AHB signals AHB signalsTable A-2lists the AHB signals Where = 0 or C, where C = ConfigurationTable A-3lists the SMC memory interface signals SMC memory interface signalsTable A-4 SMC miscellaneous signals SMC miscellaneous signalsTable A-4lists the SMC miscellaneous signals Table A-5lists the low-power interface signals Low-power interfaceName Source Description Type Destination Configuration signalTable A-6lists the configuration signal Table A-6 Configuration signalScan chains Table A-7lists the scan chain signalsTable A-7 Scan chain signals ARM DDI 0389B Advanced Microcontroller Bus Architecture Amba Advanced High-performance Bus AHBAdvanced Peripheral Bus APB See also Little-endian memoryMulti-master operation IncrementedAn 8-bit data item Data busOther purposes Divisible by fourSee Unpredictable That event resource is UnpredictableReserved Has been completedWritten as 0 and read as RemappingGlossary-6