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73 lines
2.3 KiB
C
73 lines
2.3 KiB
C
/*
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* Copyright (C) 2015 <nqdinhddt@gmail.com>
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*/
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/**
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* @ingroup cpu_sam3
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* @ingroup drivers_periph_cpuid
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* @{
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*
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* @file
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* @brief Low-level CPUID driver implementation
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*
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* @author Dinh Nguyen <nqdinhddt@gmail.com>
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*
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* @}
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*/
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#include <stdint.h>
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#include <string.h>
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#include "periph/cpuid.h"
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#define EFC_FCMD_STUI 0x0E /* Start unique ID */
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#define EFC_FCMD_SPUI 0x0F /* Stop unique ID */
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#define EFC_KEY 0x5A
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/* During the sequence, the software can not run out of Flash */
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__attribute__ ((section (".ramfunc")))
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void cpuid_get(void *id)
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{
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uint32_t cpuid[4]; /* 128 bits sam3 unique identifier */
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/*
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Reading SAM3 Unique Identifier process (P 19.3.3.8):
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- Send the Start Read unique Identifier command (STUI) by writing the Flash Command Register with the
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STUI command.
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- When the Unique Identifier is ready to be read, the FRDY bit in the Flash Programming Status Register
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(EEFC_FSR) falls
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- The Unique Identifier is located in the first 128 bits of the Flash memory mapping. So, at the address
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0x400000-0x40008F.
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- To stop the Unique Identifier mode, the user needs to send the Stop Read unique Identifier command (SPUI)
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by writing the Flash Command Register with the SPUI command.
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- When the Stop read Unique Identifier command (SPUI) has been performed, the FRDY bit in the Flash
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Programming Status Register (EEFC_FSR) rises. If an interrupt was enabled by setting the FRDY bit in
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EEFC_FMR, the interrupt line of the NVIC is activated.
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*/
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/* Send STUI */
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EFC1->EEFC_FCR = EEFC_FCR_FKEY(EFC_KEY) | EFC_FCMD_STUI;
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/* Wait for FRDY bit falls */
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while (EFC1->EEFC_FSR & EEFC_FSR_FRDY) {}
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/* Read UID */
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cpuid[0] = *(uint32_t *)IFLASH1_ADDR;
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cpuid[1] = *(uint32_t *)(IFLASH1_ADDR + 4);
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cpuid[2] = *(uint32_t *)(IFLASH1_ADDR + 8);
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cpuid[3] = *(uint32_t *)(IFLASH1_ADDR + 12);
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/* Send SPUI */
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EFC1->EEFC_FCR = EEFC_FCR_FKEY(EFC_KEY) | EFC_FCMD_SPUI ;
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/* Wait for FRDY bit rises. */
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while (0 == (EFC1->EEFC_FSR & EEFC_FSR_FRDY)) {}
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memcpy(id, (void*)cpuid, CPUID_LEN);
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}
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