SD_TEST_Create_file

Users » yueee_yt » Code » SD_TEST_Create_file

Yasushi TAUCHI / Mbed 2 deprecated SD_TEST_Create_file

SDFileSystem/SDFileSystem.cpp@0:e47238c411af, 2011-05-07 (annotated)

Committer:: yueee_yt
Date:: Sat May 07 11:08:38 2011 +0000
Revision:: 0:e47238c411af

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User	Revision	Line number	New contents of line
yueee_yt	0:e47238c411af	1	/* mbed SDFileSystem Library, for providing file access to SD cards
yueee_yt	0:e47238c411af	2	* Copyright (c) 2008-2010, sford
yueee_yt	0:e47238c411af	3	*
yueee_yt	0:e47238c411af	4	* Permission is hereby granted, free of charge, to any person obtaining a copy
yueee_yt	0:e47238c411af	5	* of this software and associated documentation files (the "Software"), to deal
yueee_yt	0:e47238c411af	6	* in the Software without restriction, including without limitation the rights
yueee_yt	0:e47238c411af	7	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
yueee_yt	0:e47238c411af	8	* copies of the Software, and to permit persons to whom the Software is
yueee_yt	0:e47238c411af	9	* furnished to do so, subject to the following conditions:
yueee_yt	0:e47238c411af	10	*
yueee_yt	0:e47238c411af	11	* The above copyright notice and this permission notice shall be included in
yueee_yt	0:e47238c411af	12	* all copies or substantial portions of the Software.
yueee_yt	0:e47238c411af	13	*
yueee_yt	0:e47238c411af	14	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
yueee_yt	0:e47238c411af	15	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
yueee_yt	0:e47238c411af	16	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
yueee_yt	0:e47238c411af	17	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
yueee_yt	0:e47238c411af	18	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
yueee_yt	0:e47238c411af	19	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
yueee_yt	0:e47238c411af	20	* THE SOFTWARE.
yueee_yt	0:e47238c411af	21	*/
yueee_yt	0:e47238c411af	22
yueee_yt	0:e47238c411af	23	/* Introduction
yueee_yt	0:e47238c411af	24	* ------------
yueee_yt	0:e47238c411af	25	* SD and MMC cards support a number of interfaces, but common to them all
yueee_yt	0:e47238c411af	26	* is one based on SPI. This is the one I'm implmenting because it means
yueee_yt	0:e47238c411af	27	* it is much more portable even though not so performant, and we already
yueee_yt	0:e47238c411af	28	* have the mbed SPI Interface!
yueee_yt	0:e47238c411af	29	*
yueee_yt	0:e47238c411af	30	* The main reference I'm using is Chapter 7, "SPI Mode" of:
yueee_yt	0:e47238c411af	31	* http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
yueee_yt	0:e47238c411af	32	*
yueee_yt	0:e47238c411af	33	* SPI Startup
yueee_yt	0:e47238c411af	34	* -----------
yueee_yt	0:e47238c411af	35	* The SD card powers up in SD mode. The SPI interface mode is selected by
yueee_yt	0:e47238c411af	36	* asserting CS low and sending the reset command (CMD0). The card will
yueee_yt	0:e47238c411af	37	* respond with a (R1) response.
yueee_yt	0:e47238c411af	38	*
yueee_yt	0:e47238c411af	39	* CMD8 is optionally sent to determine the voltage range supported, and
yueee_yt	0:e47238c411af	40	* indirectly determine whether it is a version 1.x SD/non-SD card or
yueee_yt	0:e47238c411af	41	* version 2.x. I'll just ignore this for now.
yueee_yt	0:e47238c411af	42	*
yueee_yt	0:e47238c411af	43	* ACMD41 is repeatedly issued to initialise the card, until "in idle"
yueee_yt	0:e47238c411af	44	* (bit 0) of the R1 response goes to '0', indicating it is initialised.
yueee_yt	0:e47238c411af	45	*
yueee_yt	0:e47238c411af	46	* You should also indicate whether the host supports High Capicity cards,
yueee_yt	0:e47238c411af	47	* and check whether the card is high capacity - i'll also ignore this
yueee_yt	0:e47238c411af	48	*
yueee_yt	0:e47238c411af	49	* SPI Protocol
yueee_yt	0:e47238c411af	50	* ------------
yueee_yt	0:e47238c411af	51	* The SD SPI protocol is based on transactions made up of 8-bit words, with
yueee_yt	0:e47238c411af	52	* the host starting every bus transaction by asserting the CS signal low. The
yueee_yt	0:e47238c411af	53	* card always responds to commands, data blocks and errors.
yueee_yt	0:e47238c411af	54	*
yueee_yt	0:e47238c411af	55	* The protocol supports a CRC, but by default it is off (except for the
yueee_yt	0:e47238c411af	56	* first reset CMD0, where the CRC can just be pre-calculated, and CMD8)
yueee_yt	0:e47238c411af	57	* I'll leave the CRC off I think!
yueee_yt	0:e47238c411af	58	*
yueee_yt	0:e47238c411af	59	* Standard capacity cards have variable data block sizes, whereas High
yueee_yt	0:e47238c411af	60	* Capacity cards fix the size of data block to 512 bytes. I'll therefore
yueee_yt	0:e47238c411af	61	* just always use the Standard Capacity cards with a block size of 512 bytes.
yueee_yt	0:e47238c411af	62	* This is set with CMD16.
yueee_yt	0:e47238c411af	63	*
yueee_yt	0:e47238c411af	64	* You can read and write single blocks (CMD17, CMD25) or multiple blocks
yueee_yt	0:e47238c411af	65	* (CMD18, CMD25). For simplicity, I'll just use single block accesses. When
yueee_yt	0:e47238c411af	66	* the card gets a read command, it responds with a response token, and then
yueee_yt	0:e47238c411af	67	* a data token or an error.
yueee_yt	0:e47238c411af	68	*
yueee_yt	0:e47238c411af	69	* SPI Command Format
yueee_yt	0:e47238c411af	70	* ------------------
yueee_yt	0:e47238c411af	71	* Commands are 6-bytes long, containing the command, 32-bit argument, and CRC.
yueee_yt	0:e47238c411af	72	*
yueee_yt	0:e47238c411af	73	* +---------------+------------+------------+-----------+----------+--------------+
yueee_yt	0:e47238c411af	74	* \| 01 \| cmd[5:0] \| arg[31:24] \| arg[23:16] \| arg[15:8] \| arg[7:0] \| crc[6:0] \| 1 \|
yueee_yt	0:e47238c411af	75	* +---------------+------------+------------+-----------+----------+--------------+
yueee_yt	0:e47238c411af	76	*
yueee_yt	0:e47238c411af	77	* As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95)
yueee_yt	0:e47238c411af	78	*
yueee_yt	0:e47238c411af	79	* All Application Specific commands shall be preceded with APP_CMD (CMD55).
yueee_yt	0:e47238c411af	80	*
yueee_yt	0:e47238c411af	81	* SPI Response Format
yueee_yt	0:e47238c411af	82	* -------------------
yueee_yt	0:e47238c411af	83	* The main response format (R1) is a status byte (normally zero). Key flags:
yueee_yt	0:e47238c411af	84	* idle - 1 if the card is in an idle state/initialising
yueee_yt	0:e47238c411af	85	* cmd - 1 if an illegal command code was detected
yueee_yt	0:e47238c411af	86	*
yueee_yt	0:e47238c411af	87	* +-------------------------------------------------+
yueee_yt	0:e47238c411af	88	* R1 \| 0 \| arg \| addr \| seq \| crc \| cmd \| erase \| idle \|
yueee_yt	0:e47238c411af	89	* +-------------------------------------------------+
yueee_yt	0:e47238c411af	90	*
yueee_yt	0:e47238c411af	91	* R1b is the same, except it is followed by a busy signal (zeros) until
yueee_yt	0:e47238c411af	92	* the first non-zero byte when it is ready again.
yueee_yt	0:e47238c411af	93	*
yueee_yt	0:e47238c411af	94	* Data Response Token
yueee_yt	0:e47238c411af	95	* -------------------
yueee_yt	0:e47238c411af	96	* Every data block written to the card is acknowledged by a byte
yueee_yt	0:e47238c411af	97	* response token
yueee_yt	0:e47238c411af	98	*
yueee_yt	0:e47238c411af	99	* +----------------------+
yueee_yt	0:e47238c411af	100	* \| xxx \| 0 \| status \| 1 \|
yueee_yt	0:e47238c411af	101	* +----------------------+
yueee_yt	0:e47238c411af	102	* 010 - OK!
yueee_yt	0:e47238c411af	103	* 101 - CRC Error
yueee_yt	0:e47238c411af	104	* 110 - Write Error
yueee_yt	0:e47238c411af	105	*
yueee_yt	0:e47238c411af	106	* Single Block Read and Write
yueee_yt	0:e47238c411af	107	* ---------------------------
yueee_yt	0:e47238c411af	108	*
yueee_yt	0:e47238c411af	109	* Block transfers have a byte header, followed by the data, followed
yueee_yt	0:e47238c411af	110	* by a 16-bit CRC. In our case, the data will always be 512 bytes.
yueee_yt	0:e47238c411af	111	*
yueee_yt	0:e47238c411af	112	* +------+---------+---------+- - - -+---------+-----------+----------+
yueee_yt	0:e47238c411af	113	* \| 0xFE \| data[0] \| data[1] \| \| data[n] \| crc[15:8] \| crc[7:0] \|
yueee_yt	0:e47238c411af	114	* +------+---------+---------+- - - -+---------+-----------+----------+
yueee_yt	0:e47238c411af	115	*/
yueee_yt	0:e47238c411af	116
yueee_yt	0:e47238c411af	117	#include "SDFileSystem.h"
yueee_yt	0:e47238c411af	118
yueee_yt	0:e47238c411af	119	#define SD_COMMAND_TIMEOUT 5000
yueee_yt	0:e47238c411af	120
yueee_yt	0:e47238c411af	121	SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) :
yueee_yt	0:e47238c411af	122	FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) {
yueee_yt	0:e47238c411af	123	_cs = 1;
yueee_yt	0:e47238c411af	124	}
yueee_yt	0:e47238c411af	125
yueee_yt	0:e47238c411af	126	#define R1_IDLE_STATE (1 << 0)
yueee_yt	0:e47238c411af	127	#define R1_ERASE_RESET (1 << 1)
yueee_yt	0:e47238c411af	128	#define R1_ILLEGAL_COMMAND (1 << 2)
yueee_yt	0:e47238c411af	129	#define R1_COM_CRC_ERROR (1 << 3)
yueee_yt	0:e47238c411af	130	#define R1_ERASE_SEQUENCE_ERROR (1 << 4)
yueee_yt	0:e47238c411af	131	#define R1_ADDRESS_ERROR (1 << 5)
yueee_yt	0:e47238c411af	132	#define R1_PARAMETER_ERROR (1 << 6)
yueee_yt	0:e47238c411af	133
yueee_yt	0:e47238c411af	134	// Types
yueee_yt	0:e47238c411af	135	// - v1.x Standard Capacity
yueee_yt	0:e47238c411af	136	// - v2.x Standard Capacity
yueee_yt	0:e47238c411af	137	// - v2.x High Capacity
yueee_yt	0:e47238c411af	138	// - Not recognised as an SD Card
yueee_yt	0:e47238c411af	139
yueee_yt	0:e47238c411af	140	#define SDCARD_FAIL 0
yueee_yt	0:e47238c411af	141	#define SDCARD_V1 1
yueee_yt	0:e47238c411af	142	#define SDCARD_V2 2
yueee_yt	0:e47238c411af	143	#define SDCARD_V2HC 3
yueee_yt	0:e47238c411af	144
yueee_yt	0:e47238c411af	145	int SDFileSystem::initialise_card() {
yueee_yt	0:e47238c411af	146	// Set to 100kHz for initialisation, and clock card with cs = 1
yueee_yt	0:e47238c411af	147	_spi.frequency(100000);
yueee_yt	0:e47238c411af	148	_cs = 1;
yueee_yt	0:e47238c411af	149	for(int i=0; i<16; i++) {
yueee_yt	0:e47238c411af	150	_spi.write(0xFF);
yueee_yt	0:e47238c411af	151	}
yueee_yt	0:e47238c411af	152
yueee_yt	0:e47238c411af	153	// send CMD0, should return with all zeros except IDLE STATE set (bit 0)
yueee_yt	0:e47238c411af	154	if(_cmd(0, 0) != R1_IDLE_STATE) {
yueee_yt	0:e47238c411af	155	fprintf(stderr, "No disk, or could not put SD card in to SPI idle state\n");
yueee_yt	0:e47238c411af	156	return SDCARD_FAIL;
yueee_yt	0:e47238c411af	157	}
yueee_yt	0:e47238c411af	158
yueee_yt	0:e47238c411af	159	// send CMD8 to determine whther it is ver 2.x
yueee_yt	0:e47238c411af	160	int r = _cmd8();
yueee_yt	0:e47238c411af	161	if(r == R1_IDLE_STATE) {
yueee_yt	0:e47238c411af	162	return initialise_card_v2();
yueee_yt	0:e47238c411af	163	} else if(r == (R1_IDLE_STATE \| R1_ILLEGAL_COMMAND)) {
yueee_yt	0:e47238c411af	164	return initialise_card_v1();
yueee_yt	0:e47238c411af	165	} else {
yueee_yt	0:e47238c411af	166	fprintf(stderr, "Not in idle state after sending CMD8 (not an SD card?)\n");
yueee_yt	0:e47238c411af	167	return SDCARD_FAIL;
yueee_yt	0:e47238c411af	168	}
yueee_yt	0:e47238c411af	169	}
yueee_yt	0:e47238c411af	170
yueee_yt	0:e47238c411af	171	int SDFileSystem::initialise_card_v1() {
yueee_yt	0:e47238c411af	172	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
yueee_yt	0:e47238c411af	173	_cmd(55, 0);
yueee_yt	0:e47238c411af	174	if(_cmd(41, 0) == 0) {
yueee_yt	0:e47238c411af	175	return SDCARD_V1;
yueee_yt	0:e47238c411af	176	}
yueee_yt	0:e47238c411af	177	}
yueee_yt	0:e47238c411af	178
yueee_yt	0:e47238c411af	179	fprintf(stderr, "Timeout waiting for v1.x card\n");
yueee_yt	0:e47238c411af	180	return SDCARD_FAIL;
yueee_yt	0:e47238c411af	181	}
yueee_yt	0:e47238c411af	182
yueee_yt	0:e47238c411af	183	int SDFileSystem::initialise_card_v2() {
yueee_yt	0:e47238c411af	184
yueee_yt	0:e47238c411af	185	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
yueee_yt	0:e47238c411af	186	_cmd(55, 0);
yueee_yt	0:e47238c411af	187	if(_cmd(41, 0) == 0) {
yueee_yt	0:e47238c411af	188	_cmd58();
yueee_yt	0:e47238c411af	189	return SDCARD_V2;
yueee_yt	0:e47238c411af	190	}
yueee_yt	0:e47238c411af	191	}
yueee_yt	0:e47238c411af	192
yueee_yt	0:e47238c411af	193	fprintf(stderr, "Timeout waiting for v2.x card\n");
yueee_yt	0:e47238c411af	194	return SDCARD_FAIL;
yueee_yt	0:e47238c411af	195	}
yueee_yt	0:e47238c411af	196
yueee_yt	0:e47238c411af	197	int SDFileSystem::disk_initialize() {
yueee_yt	0:e47238c411af	198
yueee_yt	0:e47238c411af	199	int i = initialise_card();
yueee_yt	0:e47238c411af	200	// printf("init card = %d\n", i);
yueee_yt	0:e47238c411af	201	// printf("OK\n");
yueee_yt	0:e47238c411af	202
yueee_yt	0:e47238c411af	203	_sectors = _sd_sectors();
yueee_yt	0:e47238c411af	204
yueee_yt	0:e47238c411af	205	// Set block length to 512 (CMD16)
yueee_yt	0:e47238c411af	206	if(_cmd(16, 512) != 0) {
yueee_yt	0:e47238c411af	207	fprintf(stderr, "Set 512-byte block timed out\n");
yueee_yt	0:e47238c411af	208	return 1;
yueee_yt	0:e47238c411af	209	}
yueee_yt	0:e47238c411af	210
yueee_yt	0:e47238c411af	211	_spi.frequency(1000000); // Set to 1MHz for data transfer
yueee_yt	0:e47238c411af	212	return 0;
yueee_yt	0:e47238c411af	213	}
yueee_yt	0:e47238c411af	214
yueee_yt	0:e47238c411af	215	int SDFileSystem::disk_write(const char *buffer, int block_number) {
yueee_yt	0:e47238c411af	216	// set write address for single block (CMD24)
yueee_yt	0:e47238c411af	217	if(_cmd(24, block_number * 512) != 0) {
yueee_yt	0:e47238c411af	218	return 1;
yueee_yt	0:e47238c411af	219	}
yueee_yt	0:e47238c411af	220
yueee_yt	0:e47238c411af	221	// send the data block
yueee_yt	0:e47238c411af	222	_write(buffer, 512);
yueee_yt	0:e47238c411af	223	return 0;
yueee_yt	0:e47238c411af	224	}
yueee_yt	0:e47238c411af	225
yueee_yt	0:e47238c411af	226	int SDFileSystem::disk_read(char *buffer, int block_number) {
yueee_yt	0:e47238c411af	227	// set read address for single block (CMD17)
yueee_yt	0:e47238c411af	228	if(_cmd(17, block_number * 512) != 0) {
yueee_yt	0:e47238c411af	229	return 1;
yueee_yt	0:e47238c411af	230	}
yueee_yt	0:e47238c411af	231
yueee_yt	0:e47238c411af	232	// receive the data
yueee_yt	0:e47238c411af	233	_read(buffer, 512);
yueee_yt	0:e47238c411af	234	return 0;
yueee_yt	0:e47238c411af	235	}
yueee_yt	0:e47238c411af	236
yueee_yt	0:e47238c411af	237	int SDFileSystem::disk_status() { return 0; }
yueee_yt	0:e47238c411af	238	int SDFileSystem::disk_sync() { return 0; }
yueee_yt	0:e47238c411af	239	int SDFileSystem::disk_sectors() { return _sectors; }
yueee_yt	0:e47238c411af	240
yueee_yt	0:e47238c411af	241	// PRIVATE FUNCTIONS
yueee_yt	0:e47238c411af	242
yueee_yt	0:e47238c411af	243	int SDFileSystem::_cmd(int cmd, int arg) {
yueee_yt	0:e47238c411af	244	_cs = 0;
yueee_yt	0:e47238c411af	245
yueee_yt	0:e47238c411af	246	// send a command
yueee_yt	0:e47238c411af	247	_spi.write(0x40 \| cmd);
yueee_yt	0:e47238c411af	248	_spi.write(arg >> 24);
yueee_yt	0:e47238c411af	249	_spi.write(arg >> 16);
yueee_yt	0:e47238c411af	250	_spi.write(arg >> 8);
yueee_yt	0:e47238c411af	251	_spi.write(arg >> 0);
yueee_yt	0:e47238c411af	252	_spi.write(0x95);
yueee_yt	0:e47238c411af	253
yueee_yt	0:e47238c411af	254	// wait for the repsonse (response[7] == 0)
yueee_yt	0:e47238c411af	255	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
yueee_yt	0:e47238c411af	256	int response = _spi.write(0xFF);
yueee_yt	0:e47238c411af	257	if(!(response & 0x80)) {
yueee_yt	0:e47238c411af	258	_cs = 1;
yueee_yt	0:e47238c411af	259	_spi.write(0xFF);
yueee_yt	0:e47238c411af	260	return response;
yueee_yt	0:e47238c411af	261	}
yueee_yt	0:e47238c411af	262	}
yueee_yt	0:e47238c411af	263	_cs = 1;
yueee_yt	0:e47238c411af	264	_spi.write(0xFF);
yueee_yt	0:e47238c411af	265	return -1; // timeout
yueee_yt	0:e47238c411af	266	}
yueee_yt	0:e47238c411af	267	int SDFileSystem::_cmdx(int cmd, int arg) {
yueee_yt	0:e47238c411af	268	_cs = 0;
yueee_yt	0:e47238c411af	269
yueee_yt	0:e47238c411af	270	// send a command
yueee_yt	0:e47238c411af	271	_spi.write(0x40 \| cmd);
yueee_yt	0:e47238c411af	272	_spi.write(arg >> 24);
yueee_yt	0:e47238c411af	273	_spi.write(arg >> 16);
yueee_yt	0:e47238c411af	274	_spi.write(arg >> 8);
yueee_yt	0:e47238c411af	275	_spi.write(arg >> 0);
yueee_yt	0:e47238c411af	276	_spi.write(0x95);
yueee_yt	0:e47238c411af	277
yueee_yt	0:e47238c411af	278	// wait for the repsonse (response[7] == 0)
yueee_yt	0:e47238c411af	279	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
yueee_yt	0:e47238c411af	280	int response = _spi.write(0xFF);
yueee_yt	0:e47238c411af	281	if(!(response & 0x80)) {
yueee_yt	0:e47238c411af	282	return response;
yueee_yt	0:e47238c411af	283	}
yueee_yt	0:e47238c411af	284	}
yueee_yt	0:e47238c411af	285	_cs = 1;
yueee_yt	0:e47238c411af	286	_spi.write(0xFF);
yueee_yt	0:e47238c411af	287	return -1; // timeout
yueee_yt	0:e47238c411af	288	}
yueee_yt	0:e47238c411af	289
yueee_yt	0:e47238c411af	290
yueee_yt	0:e47238c411af	291	int SDFileSystem::_cmd58() {
yueee_yt	0:e47238c411af	292	_cs = 0;
yueee_yt	0:e47238c411af	293	int arg = 0;
yueee_yt	0:e47238c411af	294
yueee_yt	0:e47238c411af	295	// send a command
yueee_yt	0:e47238c411af	296	_spi.write(0x40 \| 58);
yueee_yt	0:e47238c411af	297	_spi.write(arg >> 24);
yueee_yt	0:e47238c411af	298	_spi.write(arg >> 16);
yueee_yt	0:e47238c411af	299	_spi.write(arg >> 8);
yueee_yt	0:e47238c411af	300	_spi.write(arg >> 0);
yueee_yt	0:e47238c411af	301	_spi.write(0x95);
yueee_yt	0:e47238c411af	302
yueee_yt	0:e47238c411af	303	// wait for the repsonse (response[7] == 0)
yueee_yt	0:e47238c411af	304	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
yueee_yt	0:e47238c411af	305	int response = _spi.write(0xFF);
yueee_yt	0:e47238c411af	306	if(!(response & 0x80)) {
yueee_yt	0:e47238c411af	307	int ocr = _spi.write(0xFF) << 24;
yueee_yt	0:e47238c411af	308	ocr \|= _spi.write(0xFF) << 16;
yueee_yt	0:e47238c411af	309	ocr \|= _spi.write(0xFF) << 8;
yueee_yt	0:e47238c411af	310	ocr \|= _spi.write(0xFF) << 0;
yueee_yt	0:e47238c411af	311	// printf("OCR = 0x%08X\n", ocr);
yueee_yt	0:e47238c411af	312	_cs = 1;
yueee_yt	0:e47238c411af	313	_spi.write(0xFF);
yueee_yt	0:e47238c411af	314	return response;
yueee_yt	0:e47238c411af	315	}
yueee_yt	0:e47238c411af	316	}
yueee_yt	0:e47238c411af	317	_cs = 1;
yueee_yt	0:e47238c411af	318	_spi.write(0xFF);
yueee_yt	0:e47238c411af	319	return -1; // timeout
yueee_yt	0:e47238c411af	320	}
yueee_yt	0:e47238c411af	321
yueee_yt	0:e47238c411af	322	int SDFileSystem::_cmd8() {
yueee_yt	0:e47238c411af	323	_cs = 0;
yueee_yt	0:e47238c411af	324
yueee_yt	0:e47238c411af	325	// send a command
yueee_yt	0:e47238c411af	326	_spi.write(0x40 \| 8); // CMD8
yueee_yt	0:e47238c411af	327	_spi.write(0x00); // reserved
yueee_yt	0:e47238c411af	328	_spi.write(0x00); // reserved
yueee_yt	0:e47238c411af	329	_spi.write(0x01); // 3.3v
yueee_yt	0:e47238c411af	330	_spi.write(0xAA); // check pattern
yueee_yt	0:e47238c411af	331	_spi.write(0x87); // crc
yueee_yt	0:e47238c411af	332
yueee_yt	0:e47238c411af	333	// wait for the repsonse (response[7] == 0)
yueee_yt	0:e47238c411af	334	for(int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) {
yueee_yt	0:e47238c411af	335	char response[5];
yueee_yt	0:e47238c411af	336	response[0] = _spi.write(0xFF);
yueee_yt	0:e47238c411af	337	if(!(response[0] & 0x80)) {
yueee_yt	0:e47238c411af	338	for(int j=1; j<5; j++) {
yueee_yt	0:e47238c411af	339	response[i] = _spi.write(0xFF);
yueee_yt	0:e47238c411af	340	}
yueee_yt	0:e47238c411af	341	_cs = 1;
yueee_yt	0:e47238c411af	342	_spi.write(0xFF);
yueee_yt	0:e47238c411af	343	return response[0];
yueee_yt	0:e47238c411af	344	}
yueee_yt	0:e47238c411af	345	}
yueee_yt	0:e47238c411af	346	_cs = 1;
yueee_yt	0:e47238c411af	347	_spi.write(0xFF);
yueee_yt	0:e47238c411af	348	return -1; // timeout
yueee_yt	0:e47238c411af	349	}
yueee_yt	0:e47238c411af	350
yueee_yt	0:e47238c411af	351	int SDFileSystem::_read(char *buffer, int length) {
yueee_yt	0:e47238c411af	352	_cs = 0;
yueee_yt	0:e47238c411af	353
yueee_yt	0:e47238c411af	354	// read until start byte (0xFF)
yueee_yt	0:e47238c411af	355	while(_spi.write(0xFF) != 0xFE);
yueee_yt	0:e47238c411af	356
yueee_yt	0:e47238c411af	357	// read data
yueee_yt	0:e47238c411af	358	for(int i=0; i<length; i++) {
yueee_yt	0:e47238c411af	359	buffer[i] = _spi.write(0xFF);
yueee_yt	0:e47238c411af	360	}
yueee_yt	0:e47238c411af	361	_spi.write(0xFF); // checksum
yueee_yt	0:e47238c411af	362	_spi.write(0xFF);
yueee_yt	0:e47238c411af	363
yueee_yt	0:e47238c411af	364	_cs = 1;
yueee_yt	0:e47238c411af	365	_spi.write(0xFF);
yueee_yt	0:e47238c411af	366	return 0;
yueee_yt	0:e47238c411af	367	}
yueee_yt	0:e47238c411af	368
yueee_yt	0:e47238c411af	369	int SDFileSystem::_write(const char *buffer, int length) {
yueee_yt	0:e47238c411af	370	_cs = 0;
yueee_yt	0:e47238c411af	371
yueee_yt	0:e47238c411af	372	// indicate start of block
yueee_yt	0:e47238c411af	373	_spi.write(0xFE);
yueee_yt	0:e47238c411af	374
yueee_yt	0:e47238c411af	375	// write the data
yueee_yt	0:e47238c411af	376	for(int i=0; i<length; i++) {
yueee_yt	0:e47238c411af	377	_spi.write(buffer[i]);
yueee_yt	0:e47238c411af	378	}
yueee_yt	0:e47238c411af	379
yueee_yt	0:e47238c411af	380	// write the checksum
yueee_yt	0:e47238c411af	381	_spi.write(0xFF);
yueee_yt	0:e47238c411af	382	_spi.write(0xFF);
yueee_yt	0:e47238c411af	383
yueee_yt	0:e47238c411af	384	// check the repsonse token
yueee_yt	0:e47238c411af	385	if((_spi.write(0xFF) & 0x1F) != 0x05) {
yueee_yt	0:e47238c411af	386	_cs = 1;
yueee_yt	0:e47238c411af	387	_spi.write(0xFF);
yueee_yt	0:e47238c411af	388	return 1;
yueee_yt	0:e47238c411af	389	}
yueee_yt	0:e47238c411af	390
yueee_yt	0:e47238c411af	391	// wait for write to finish
yueee_yt	0:e47238c411af	392	while(_spi.write(0xFF) == 0);
yueee_yt	0:e47238c411af	393
yueee_yt	0:e47238c411af	394	_cs = 1;
yueee_yt	0:e47238c411af	395	_spi.write(0xFF);
yueee_yt	0:e47238c411af	396	return 0;
yueee_yt	0:e47238c411af	397	}
yueee_yt	0:e47238c411af	398
yueee_yt	0:e47238c411af	399	static int ext_bits(char *data, int msb, int lsb) {
yueee_yt	0:e47238c411af	400	int bits = 0;
yueee_yt	0:e47238c411af	401	int size = 1 + msb - lsb;
yueee_yt	0:e47238c411af	402	for(int i=0; i<size; i++) {
yueee_yt	0:e47238c411af	403	int position = lsb + i;
yueee_yt	0:e47238c411af	404	int byte = 15 - (position >> 3);
yueee_yt	0:e47238c411af	405	int bit = position & 0x7;
yueee_yt	0:e47238c411af	406	int value = (data[byte] >> bit) & 1;
yueee_yt	0:e47238c411af	407	bits \|= value << i;
yueee_yt	0:e47238c411af	408	}
yueee_yt	0:e47238c411af	409	return bits;
yueee_yt	0:e47238c411af	410	}
yueee_yt	0:e47238c411af	411
yueee_yt	0:e47238c411af	412	int SDFileSystem::_sd_sectors() {
yueee_yt	0:e47238c411af	413
yueee_yt	0:e47238c411af	414	// CMD9, Response R2 (R1 byte + 16-byte block read)
yueee_yt	0:e47238c411af	415	if(_cmdx(9, 0) != 0) {
yueee_yt	0:e47238c411af	416	fprintf(stderr, "Didn't get a response from the disk\n");
yueee_yt	0:e47238c411af	417	return 0;
yueee_yt	0:e47238c411af	418	}
yueee_yt	0:e47238c411af	419
yueee_yt	0:e47238c411af	420	char csd[16];
yueee_yt	0:e47238c411af	421	if(_read(csd, 16) != 0) {
yueee_yt	0:e47238c411af	422	fprintf(stderr, "Couldn't read csd response from disk\n");
yueee_yt	0:e47238c411af	423	return 0;
yueee_yt	0:e47238c411af	424	}
yueee_yt	0:e47238c411af	425
yueee_yt	0:e47238c411af	426	// csd_structure : csd[127:126]
yueee_yt	0:e47238c411af	427	// c_size : csd[73:62]
yueee_yt	0:e47238c411af	428	// c_size_mult : csd[49:47]
yueee_yt	0:e47238c411af	429	// read_bl_len : csd[83:80] - the maximum read block length
yueee_yt	0:e47238c411af	430
yueee_yt	0:e47238c411af	431	int csd_structure = ext_bits(csd, 127, 126);
yueee_yt	0:e47238c411af	432	int c_size = ext_bits(csd, 73, 62);
yueee_yt	0:e47238c411af	433	int c_size_mult = ext_bits(csd, 49, 47);
yueee_yt	0:e47238c411af	434	int read_bl_len = ext_bits(csd, 83, 80);
yueee_yt	0:e47238c411af	435
yueee_yt	0:e47238c411af	436	// printf("CSD_STRUCT = %d\n", csd_structure);
yueee_yt	0:e47238c411af	437
yueee_yt	0:e47238c411af	438	if(csd_structure != 0) {
yueee_yt	0:e47238c411af	439	fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures\n");
yueee_yt	0:e47238c411af	440	return 0;
yueee_yt	0:e47238c411af	441	}
yueee_yt	0:e47238c411af	442
yueee_yt	0:e47238c411af	443	// memory capacity = BLOCKNR * BLOCK_LEN
yueee_yt	0:e47238c411af	444	// where
yueee_yt	0:e47238c411af	445	// BLOCKNR = (C_SIZE+1) * MULT
yueee_yt	0:e47238c411af	446	// MULT = 2^(C_SIZE_MULT+2) (C_SIZE_MULT < 8)
yueee_yt	0:e47238c411af	447	// BLOCK_LEN = 2^READ_BL_LEN, (READ_BL_LEN < 12)
yueee_yt	0:e47238c411af	448
yueee_yt	0:e47238c411af	449	int block_len = 1 << read_bl_len;
yueee_yt	0:e47238c411af	450	int mult = 1 << (c_size_mult + 2);
yueee_yt	0:e47238c411af	451	int blocknr = (c_size + 1) * mult;
yueee_yt	0:e47238c411af	452	int capacity = blocknr * block_len;
yueee_yt	0:e47238c411af	453
yueee_yt	0:e47238c411af	454	int blocks = capacity / 512;
yueee_yt	0:e47238c411af	455
yueee_yt	0:e47238c411af	456	return blocks;
yueee_yt	0:e47238c411af	457	}

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	07 May 2011
Imports:	71
Forks:	0
Commits:	1
Dependents:	0
Dependencies:	2
Followers:	2

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SDFileSystem/SDFileSystem.cpp@0:e47238c411af, 2011-05-07 (annotated)

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