Hello,
I'm having trouble accessing an external SRAM. The SRAM is selected via CSX1 (Pad L14 – GPIO_AD_26), and my test program always triggers a MemoryManage Fault. What mistake did I make in my code? Thank you in advance for your help.
/*
* Copyright 2017 NXP
* All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include "board.h"
#include "fsl_debug_console.h"
#include "fsl_device_registers.h"
#include "pin_mux.h"
#include "fsl_semc.h"
#include "clock_config.h"
/*******************************************************************************
* Definitions
******************************************************************************/
#define EXAMPLE_SEMC SEMC
#define EXAMPLE_SEMC_CLK_FREQ CLOCK_GetRootClockFreq(kCLOCK_Root_Semc)
/*******************************************************************************
* Prototypes
******************************************************************************/
extern status_t BOARD_InitSRAM(void);
/*******************************************************************************
* Variables
******************************************************************************/
/*******************************************************************************
* Code
******************************************************************************/
#define SRAM_BASE 0x60000000
//#define SRAM_BASE 0x81000000
status_t BOARD_InitAsyncSRAM_CS1(void)
{
semc_config_t config;
semc_sram_config_t xsram_config;
uint32_t clockFrq = kCLOCK_Root_Semc;
SEMC_GetDefaultConfig(&config);
config.dqsMode = kSEMC_Loopbackdqspad;
SEMC_Init(SEMC, &config);
memset(&config, 0, sizeof(semc_config_t));
memset(&xsram_config, 0, sizeof(semc_sram_config_t));
xsram_config.address = 0x60000000;
xsram_config.memsize_kbytes = 512;
xsram_config.addrPortWidth = 16;
xsram_config.portSize = kSEMC_PortSize16Bit;
xsram_config.addrMode = kSEMC_AddrDataNonMux;
xsram_config.syncMode = kSEMC_AsyncMode;
xsram_config.advActivePolarity = kSEMC_AdvActiveLow;
xsram_config.advLevelCtrl = kSEMC_AdvLow;
xsram_config.burstLen = kSEMC_Nor_BurstLen1;
xsram_config.tWeLow_Ns = 25;
xsram_config.tWeHigh_Ns = 25;
xsram_config.tReLow_Ns = 25;
xsram_config.tReHigh_Ns = 25;
xsram_config.tTurnAround_Ns = 10;
xsram_config.cePinMux = kSEMC_MUXCSX1;
xsram_config.waitEnable = true;
xsram_config.waitSample = true;
xsram_config.tCeSetup_Ns = 25;
xsram_config.tCeHold_Ns = 20;
xsram_config.tAddrSetup_Ns = 25;
xsram_config.tAddrHold_Ns = 25;
xsram_config.tWriteSetup_Ns = 25;
xsram_config.tWriteHold_Ns = 25;
xsram_config.readCycle = 30;
xsram_config.readHoldTime_Ns = 25;
xsram_config.tCeInterval_Ns = 25;
xsram_config.tAddr2WriteHold_Ns = 25;
xsram_config.latencyCount = 3;
xsram_config.delayChain = 25;
xsram_config.addr27 = kSEMC_MORA27_NONE;
SEMC->IOCR |= 0x00908BB6;
// SEMC->IOCR |= 0x08;
return SEMC_ConfigureSRAMWithChipSelection(SEMC, kSEMC_SRAM_CS1, &xsram_config, clockFrq);
}
/*!
* @brief Main function
*/
int main(void)
{
/* Hardware initialize. */
BOARD_ConfigMPU();
BOARD_InitPins();
BOARD_BootClockRUN();
BOARD_InitDebugConsole();
BOARD_InitAsyncSRAM_CS1();
SEMC->IOCR |= SEMC_IOCR_MUX_CSX1(0x08);
PRINTF("\r\n Start SEMC SRAM MSpec with WAIT write test.\r\n");
PRINTF("CCM_OBS_SEMC_CLK_ROOT： %d\r\n", CLOCK_GetFreqFromObs(CCM_OBS_SEMC_CLK_ROOT));
//////////////////////////////////////////////////////////////////////////////////////////////
volatile uint16_t *sram_ptr = (volatile uint16_t *)0x60000000;
uint16_t i = 0;
*sram_ptr = 0;
for (i = 0; i <= 10; i++)
{
*sram_ptr = i;
}
for (i = 0; i <= 10; i++)
{
PRINTF("\r\n sram = %d \r\n", sram_ptr);
}
}
Hi @RainerHL ,
Thank you so much for your interest in our products and for using our community.
1: Your code configures SEMC SRAM on CSX1/CS1 , but the test accesses 0x60000000 , which is not the valid SEMC SRAM mapping for i.MX RT1170. This is the primary reason for the MemoryManage Fault.
Please use the SEMC SRAM base address window corresponding to the configured CSX1 device instead of 0x60000000.
2: your manual IOCR writes. The reference manual says IOCR configuration should be static; dynamic remapping is not supported .
3: Please check MPU configuration in your project.
4:PRINTF("\r\n sram = %d \r\n", sram_ptr);
This prints the pointer value, not the SRAM data. It should dereference the pointer, for example *sram_ptr , but that is not the cause of the MemoryManage fault.
Wish it helps you
Best Regards
May