/************************************************************************************
* configs/stm3220g-eval/src/stm32_selectsram.c
*
* Copyright (C) 2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
************************************************************************************/
/************************************************************************************
* Included Files
************************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <debug.h>
#include "chip.h"
#include "up_arch.h"
#include "stm32.h"
#include "stm3220g-internal.h"
#ifdef CONFIG_STM32_FSMC
/************************************************************************************
* Pre-processor Definitions
************************************************************************************/
#if STM32_NGPIO_PORTS < 6
# error "Required GPIO ports not enabled"
#endif
/* SRAM Timing */
#define SRAM_ADDRESS_SETUP_TIME 3
#define SRAM_ADDRESS_HOLD_TIME 0
#define SRAM_DATA_SETUP_TIME 6
#define SRAM_BUS_TURNAROUND_DURATION 1
#define SRAM_CLK_DIVISION 0
#define SRAM_DATA_LATENCY 0
/* SRAM pin definitions */
#define SRAM_NADDRLINES 21
#define SRAM_NDATALINES 16
/************************************************************************************
* Public Data
************************************************************************************/
/************************************************************************************
* Private Data
************************************************************************************/
/* GPIOs Configuration **************************************************************
* PD0 <-> FSMC_D2 PE0 <-> FSMC_NBL0 PF0 <-> FSMC_A0 PG0 <-> FSMC_A10
* PD1 <-> FSMC_D3 PE1 <-> FSMC_NBL1 PF1 <-> FSMC_A1 PG1 <-> FSMC_A11
* PD4 <-> FSMC_NOE PE3 <-> FSMC_A19 PF2 <-> FSMC_A2 PG2 <-> FSMC_A12
* PD5 <-> FSMC_NWE PE4 <-> FSMC_A20 PF3 <-> FSMC_A3 PG3 <-> FSMC_A13
* PD8 <-> FSMC_D13 PE7 <-> FSMC_D4 PF4 <-> FSMC_A4 PG4 <-> FSMC_A14
* PD9 <-> FSMC_D14 PE8 <-> FSMC_D5 PF5 <-> FSMC_A5 PG5 <-> FSMC_A15
* PD10 <-> FSMC_D15 PE9 <-> FSMC_D6 PF12 <-> FSMC_A6 PG9 <-> FSMC_NE2
* PD11 <-> FSMC_A16 PE10 <-> FSMC_D7 PF13 <-> FSMC_A7
* PD12 <-> FSMC_A17 PE11 <-> FSMC_D8 PF14 <-> FSMC_A8
* PD13 <-> FSMC_A18 PE12 <-> FSMC_D9 PF15 <-> FSMC_A9
* PD14 <-> FSMC_D0 PE13 <-> FSMC_D10
* PD15 <-> FSMC_D1 PE14 <-> FSMC_D11
* PE15 <-> FSMC_D12
*/
/* GPIO configurations unique to SRAM */
static const uint32_t g_sramconfig[] =
{
/* NE3, NBL0, NBL1, */
GPIO_FSMC_NOE, GPIO_FSMC_NWE, GPIO_FSMC_NBL0, GPIO_FSMC_NBL1, GPIO_FSMC_NE2
};
#define NSRAM_CONFIG (sizeof(g_sramconfig)/sizeof(uint32_t))
/************************************************************************************
* Private Functions
************************************************************************************/
/************************************************************************************
* Public Functions
************************************************************************************/
/************************************************************************************
* Name: stm32_selectsram
*
* Description:
* Initialize to access external SRAM. SRAM will be visible at the FSMC Bank
* NOR/SRAM2 base address (0x64000000)
*
* General transaction rules. The requested AHB transaction data size can be 8-,
* 16- or 32-bit wide whereas the SRAM has a fixed 16-bit data width. Some simple
* transaction rules must be followed:
*
* Case 1: AHB transaction width and SRAM data width are equal
* There is no issue in this case.
* Case 2: AHB transaction size is greater than the memory size
* In this case, the FSMC splits the AHB transaction into smaller consecutive
* memory accesses in order to meet the external data width.
* Case 3: AHB transaction size is smaller than the memory size.
* SRAM supports the byte select feature.
* a) FSMC allows write transactions accessing the right data through its
* byte lanes (NBL[1:0])
* b) Read transactions are allowed (the controller reads the entire memory
* word and uses the needed byte only). The NBL[1:0] are always kept low
* during read transactions.
*
************************************************************************************/
void stm32_selectsram(void)
{
/* Configure new GPIO pins */
stm32_extmemaddr(SRAM_NADDRLINES); /* Common address lines: A0-A20 */
stm32_extmemdata(SRAM_NDATALINES); /* Common data lines: D0-D15 */
stm32_extmemgpios(g_sramconfig, NSRAM_CONFIG); /* SRAM-specific control lines */
/* Enable AHB clocking to the FSMC */
stm32_enablefsmc();
/* Bank1 NOR/SRAM control register configuration
*
* Bank enable : Not yet
* Data address mux : Disabled
* Memory Type : PSRAM
* Data bus width : 16-bits
* Flash access : Disabled
* Burst access mode : Disabled
* Polarity : Low
* Wrapped burst mode : Disabled
* Write timing : Before state
* Write enable : Yes
* Wait signal : Disabled
* Extended mode : Disabled
* Asynchronous wait : Disabled
* Write burst : Disabled
*/
putreg32((FSMC_BCR_PSRAM | FSMC_BCR_MWID16 | FSMC_BCR_WREN), STM32_FSMC_BCR2);
/* Bank1 NOR/SRAM timing register configuration */
putreg32((FSMC_BTR_ADDSET(SRAM_ADDRESS_SETUP_TIME) | FSMC_BTR_ADDHLD(SRAM_ADDRESS_HOLD_TIME) |
FSMC_BTR_DATAST(SRAM_DATA_SETUP_TIME) | FSMC_BTR_BUSTRUN(SRAM_BUS_TURNAROUND_DURATION) |
FSMC_BTR_CLKDIV(SRAM_CLK_DIVISION) | FSMC_BTR_DATLAT(SRAM_DATA_LATENCY) |
FSMC_BTR_ACCMODA),
STM32_FSMC_BTR2);
/* Bank1 NOR/SRAM timing register for write configuration, if extended mode is used */
putreg32(0xffffffff, STM32_FSMC_BWTR2); /* Extended mode not used */
/* Enable the bank */
putreg32((FSMC_BCR_MBKEN | FSMC_BCR_PSRAM | FSMC_BCR_MWID16 | FSMC_BCR_WREN), STM32_FSMC_BCR2);
}
#endif /* CONFIG_STM32_FSMC */
