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Dependencies: EthernetNetIf TextLCD mbed PS2 HTTPClient

SDFileSystem.cpp@0:c69af1faeb95, 2011-02-28 (annotated)

Committer:: benglish6
Date:: Mon Feb 28 16:56:11 2011 +0000
Revision:: 0:c69af1faeb95

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User	Revision	Line number	New contents of line
benglish6	0:c69af1faeb95	1	/* mbed SDFileSystem Library, for providing file access to SD cards
benglish6	0:c69af1faeb95	2	* Copyright (c) 2008-2010, sford
benglish6	0:c69af1faeb95	3	*
benglish6	0:c69af1faeb95	4	* Permission is hereby granted, free of charge, to any person obtaining a copy
benglish6	0:c69af1faeb95	5	* of this software and associated documentation files (the "Software"), to deal
benglish6	0:c69af1faeb95	6	* in the Software without restriction, including without limitation the rights
benglish6	0:c69af1faeb95	7	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
benglish6	0:c69af1faeb95	8	* copies of the Software, and to permit persons to whom the Software is
benglish6	0:c69af1faeb95	9	* furnished to do so, subject to the following conditions:
benglish6	0:c69af1faeb95	10	*
benglish6	0:c69af1faeb95	11	* The above copyright notice and this permission notice shall be included in
benglish6	0:c69af1faeb95	12	* all copies or substantial portions of the Software.
benglish6	0:c69af1faeb95	13	*
benglish6	0:c69af1faeb95	14	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
benglish6	0:c69af1faeb95	15	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
benglish6	0:c69af1faeb95	16	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
benglish6	0:c69af1faeb95	17	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
benglish6	0:c69af1faeb95	18	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
benglish6	0:c69af1faeb95	19	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
benglish6	0:c69af1faeb95	20	* THE SOFTWARE.
benglish6	0:c69af1faeb95	21	*/
benglish6	0:c69af1faeb95	22
benglish6	0:c69af1faeb95	23	/* Introduction
benglish6	0:c69af1faeb95	24	* ------------
benglish6	0:c69af1faeb95	25	* SD and MMC cards support a number of interfaces, but common to them all
benglish6	0:c69af1faeb95	26	* is one based on SPI. This is the one I'm implmenting because it means
benglish6	0:c69af1faeb95	27	* it is much more portable even though not so performant, and we already
benglish6	0:c69af1faeb95	28	* have the mbed SPI Interface!
benglish6	0:c69af1faeb95	29	*
benglish6	0:c69af1faeb95	30	* The main reference I'm using is Chapter 7, "SPI Mode" of:
benglish6	0:c69af1faeb95	31	* http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
benglish6	0:c69af1faeb95	32	*
benglish6	0:c69af1faeb95	33	* SPI Startup
benglish6	0:c69af1faeb95	34	* -----------
benglish6	0:c69af1faeb95	35	* The SD card powers up in SD mode. The SPI interface mode is selected by
benglish6	0:c69af1faeb95	36	* asserting CS low and sending the reset command (CMD0). The card will
benglish6	0:c69af1faeb95	37	* respond with a (R1) response.
benglish6	0:c69af1faeb95	38	*
benglish6	0:c69af1faeb95	39	* CMD8 is optionally sent to determine the voltage range supported, and
benglish6	0:c69af1faeb95	40	* indirectly determine whether it is a version 1.x SD/non-SD card or
benglish6	0:c69af1faeb95	41	* version 2.x. I'll just ignore this for now.
benglish6	0:c69af1faeb95	42	*
benglish6	0:c69af1faeb95	43	* ACMD41 is repeatedly issued to initialise the card, until "in idle"
benglish6	0:c69af1faeb95	44	* (bit 0) of the R1 response goes to '0', indicating it is initialised.
benglish6	0:c69af1faeb95	45	*
benglish6	0:c69af1faeb95	46	* You should also indicate whether the host supports High Capicity cards,
benglish6	0:c69af1faeb95	47	* and check whether the card is high capacity - i'll also ignore this
benglish6	0:c69af1faeb95	48	*
benglish6	0:c69af1faeb95	49	* SPI Protocol
benglish6	0:c69af1faeb95	50	* ------------
benglish6	0:c69af1faeb95	51	* The SD SPI protocol is based on transactions made up of 8-bit words, with
benglish6	0:c69af1faeb95	52	* the host starting every bus transaction by asserting the CS signal low. The
benglish6	0:c69af1faeb95	53	* card always responds to commands, data blocks and errors.
benglish6	0:c69af1faeb95	54	*
benglish6	0:c69af1faeb95	55	* The protocol supports a CRC, but by default it is off (except for the
benglish6	0:c69af1faeb95	56	* first reset CMD0, where the CRC can just be pre-calculated, and CMD8)
benglish6	0:c69af1faeb95	57	* I'll leave the CRC off I think!
benglish6	0:c69af1faeb95	58	*
benglish6	0:c69af1faeb95	59	* Standard capacity cards have variable data block sizes, whereas High
benglish6	0:c69af1faeb95	60	* Capacity cards fix the size of data block to 512 bytes. I'll therefore
benglish6	0:c69af1faeb95	61	* just always use the Standard Capacity cards with a block size of 512 bytes.
benglish6	0:c69af1faeb95	62	* This is set with CMD16.
benglish6	0:c69af1faeb95	63	*
benglish6	0:c69af1faeb95	64	* You can read and write single blocks (CMD17, CMD25) or multiple blocks
benglish6	0:c69af1faeb95	65	* (CMD18, CMD25). For simplicity, I'll just use single block accesses. When
benglish6	0:c69af1faeb95	66	* the card gets a read command, it responds with a response token, and then
benglish6	0:c69af1faeb95	67	* a data token or an error.
benglish6	0:c69af1faeb95	68	*
benglish6	0:c69af1faeb95	69	* SPI Command Format
benglish6	0:c69af1faeb95	70	* ------------------
benglish6	0:c69af1faeb95	71	* Commands are 6-bytes long, containing the command, 32-bit argument, and CRC.
benglish6	0:c69af1faeb95	72	*
benglish6	0:c69af1faeb95	73	* +---------------+------------+------------+-----------+----------+--------------+
benglish6	0:c69af1faeb95	74	* \| 01 \| cmd[5:0] \| arg[31:24] \| arg[23:16] \| arg[15:8] \| arg[7:0] \| crc[6:0] \| 1 \|
benglish6	0:c69af1faeb95	75	* +---------------+------------+------------+-----------+----------+--------------+
benglish6	0:c69af1faeb95	76	*
benglish6	0:c69af1faeb95	77	* As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95)
benglish6	0:c69af1faeb95	78	*
benglish6	0:c69af1faeb95	79	* All Application Specific commands shall be preceded with APP_CMD (CMD55).
benglish6	0:c69af1faeb95	80	*
benglish6	0:c69af1faeb95	81	* SPI Response Format
benglish6	0:c69af1faeb95	82	* -------------------
benglish6	0:c69af1faeb95	83	* The main response format (R1) is a status byte (normally zero). Key flags:
benglish6	0:c69af1faeb95	84	* idle - 1 if the card is in an idle state/initialising
benglish6	0:c69af1faeb95	85	* cmd - 1 if an illegal command code was detected
benglish6	0:c69af1faeb95	86	*
benglish6	0:c69af1faeb95	87	* +-------------------------------------------------+
benglish6	0:c69af1faeb95	88	* R1 \| 0 \| arg \| addr \| seq \| crc \| cmd \| erase \| idle \|
benglish6	0:c69af1faeb95	89	* +-------------------------------------------------+
benglish6	0:c69af1faeb95	90	*
benglish6	0:c69af1faeb95	91	* R1b is the same, except it is followed by a busy signal (zeros) until
benglish6	0:c69af1faeb95	92	* the first non-zero byte when it is ready again.
benglish6	0:c69af1faeb95	93	*
benglish6	0:c69af1faeb95	94	* Data Response Token
benglish6	0:c69af1faeb95	95	* -------------------
benglish6	0:c69af1faeb95	96	* Every data block written to the card is acknowledged by a byte
benglish6	0:c69af1faeb95	97	* response token
benglish6	0:c69af1faeb95	98	*
benglish6	0:c69af1faeb95	99	* +----------------------+
benglish6	0:c69af1faeb95	100	* \| xxx \| 0 \| status \| 1 \|
benglish6	0:c69af1faeb95	101	* +----------------------+
benglish6	0:c69af1faeb95	102	* 010 - OK!
benglish6	0:c69af1faeb95	103	* 101 - CRC Error
benglish6	0:c69af1faeb95	104	* 110 - Write Error
benglish6	0:c69af1faeb95	105	*
benglish6	0:c69af1faeb95	106	* Single Block Read and Write
benglish6	0:c69af1faeb95	107	* ---------------------------
benglish6	0:c69af1faeb95	108	*
benglish6	0:c69af1faeb95	109	* Block transfers have a byte header, followed by the data, followed
benglish6	0:c69af1faeb95	110	* by a 16-bit CRC. In our case, the data will always be 512 bytes.
benglish6	0:c69af1faeb95	111	*
benglish6	0:c69af1faeb95	112	* +------+---------+---------+- - - -+---------+-----------+----------+
benglish6	0:c69af1faeb95	113	* \| 0xFE \| data[0] \| data[1] \| \| data[n] \| crc[15:8] \| crc[7:0] \|
benglish6	0:c69af1faeb95	114	* +------+---------+---------+- - - -+---------+-----------+----------+
benglish6	0:c69af1faeb95	115	*/
benglish6	0:c69af1faeb95	116
benglish6	0:c69af1faeb95	117	#include "SDFileSystem.h"
benglish6	0:c69af1faeb95	118
benglish6	0:c69af1faeb95	119	#define SD_COMMAND_TIMEOUT 5000
benglish6	0:c69af1faeb95	120
benglish6	0:c69af1faeb95	121	SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) :
benglish6	0:c69af1faeb95	122	FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) {
benglish6	0:c69af1faeb95	123	_cs = 1;
benglish6	0:c69af1faeb95	124	}
benglish6	0:c69af1faeb95	125
benglish6	0:c69af1faeb95	126	#define R1_IDLE_STATE (1 << 0)
benglish6	0:c69af1faeb95	127	#define R1_ERASE_RESET (1 << 1)
benglish6	0:c69af1faeb95	128	#define R1_ILLEGAL_COMMAND (1 << 2)
benglish6	0:c69af1faeb95	129	#define R1_COM_CRC_ERROR (1 << 3)
benglish6	0:c69af1faeb95	130	#define R1_ERASE_SEQUENCE_ERROR (1 << 4)
benglish6	0:c69af1faeb95	131	#define R1_ADDRESS_ERROR (1 << 5)
benglish6	0:c69af1faeb95	132	#define R1_PARAMETER_ERROR (1 << 6)
benglish6	0:c69af1faeb95	133
benglish6	0:c69af1faeb95	134	// Types
benglish6	0:c69af1faeb95	135	// - v1.x Standard Capacity
benglish6	0:c69af1faeb95	136	// - v2.x Standard Capacity
benglish6	0:c69af1faeb95	137	// - v2.x High Capacity
benglish6	0:c69af1faeb95	138	// - Not recognised as an SD Card
benglish6	0:c69af1faeb95	139
benglish6	0:c69af1faeb95	140	#define SDCARD_FAIL 0
benglish6	0:c69af1faeb95	141	#define SDCARD_V1 1
benglish6	0:c69af1faeb95	142	#define SDCARD_V2 2
benglish6	0:c69af1faeb95	143	#define SDCARD_V2HC 3
benglish6	0:c69af1faeb95	144
benglish6	0:c69af1faeb95	145	int SDFileSystem::initialise_card() {
benglish6	0:c69af1faeb95	146	// Set to 100kHz for initialisation, and clock card with cs = 1
benglish6	0:c69af1faeb95	147	_spi.frequency(100000);
benglish6	0:c69af1faeb95	148	_cs = 1;
benglish6	0:c69af1faeb95	149	for(int i=0; i<16; i++) {
benglish6	0:c69af1faeb95	150	_spi.write(0xFF);
benglish6	0:c69af1faeb95	151	}
benglish6	0:c69af1faeb95	152
benglish6	0:c69af1faeb95	153	// send CMD0, should return with all zeros except IDLE STATE set (bit 0)
benglish6	0:c69af1faeb95	154	if(_cmd(0, 0) != R1_IDLE_STATE) {
benglish6	0:c69af1faeb95	155	fprintf(stderr, "No disk, or could not put SD card in to SPI idle state\n");
benglish6	0:c69af1faeb95	156	return SDCARD_FAIL;
benglish6	0:c69af1faeb95	157	}
benglish6	0:c69af1faeb95	158
benglish6	0:c69af1faeb95	159	// send CMD8 to determine whther it is ver 2.x
benglish6	0:c69af1faeb95	160	int r = _cmd8();
benglish6	0:c69af1faeb95	161	if(r == R1_IDLE_STATE) {
benglish6	0:c69af1faeb95	162	return initialise_card_v2();
benglish6	0:c69af1faeb95	163	} else if(r == (R1_IDLE_STATE \| R1_ILLEGAL_COMMAND)) {
benglish6	0:c69af1faeb95	164	return initialise_card_v1();
benglish6	0:c69af1faeb95	165	} else {
benglish6	0:c69af1faeb95	166	fprintf(stderr, "Not in idle state after sending CMD8 (not an SD card?)\n");
benglish6	0:c69af1faeb95	167	return SDCARD_FAIL;
benglish6	0:c69af1faeb95	168	}
benglish6	0:c69af1faeb95	169	}
benglish6	0:c69af1faeb95	170
benglish6	0:c69af1faeb95	171	int SDFileSystem::initialise_card_v1() {
benglish6	0:c69af1faeb95	172	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
benglish6	0:c69af1faeb95	173	_cmd(55, 0);
benglish6	0:c69af1faeb95	174	if(_cmd(41, 0) == 0) {
benglish6	0:c69af1faeb95	175	return SDCARD_V1;
benglish6	0:c69af1faeb95	176	}
benglish6	0:c69af1faeb95	177	}
benglish6	0:c69af1faeb95	178
benglish6	0:c69af1faeb95	179	fprintf(stderr, "Timeout waiting for v1.x card\n");
benglish6	0:c69af1faeb95	180	return SDCARD_FAIL;
benglish6	0:c69af1faeb95	181	}
benglish6	0:c69af1faeb95	182
benglish6	0:c69af1faeb95	183	int SDFileSystem::initialise_card_v2() {
benglish6	0:c69af1faeb95	184
benglish6	0:c69af1faeb95	185	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
benglish6	0:c69af1faeb95	186	_cmd(55, 0);
benglish6	0:c69af1faeb95	187	if(_cmd(41, 0) == 0) {
benglish6	0:c69af1faeb95	188	_cmd58();
benglish6	0:c69af1faeb95	189	return SDCARD_V2;
benglish6	0:c69af1faeb95	190	}
benglish6	0:c69af1faeb95	191	}
benglish6	0:c69af1faeb95	192
benglish6	0:c69af1faeb95	193	fprintf(stderr, "Timeout waiting for v2.x card\n");
benglish6	0:c69af1faeb95	194	return SDCARD_FAIL;
benglish6	0:c69af1faeb95	195	}
benglish6	0:c69af1faeb95	196
benglish6	0:c69af1faeb95	197	int SDFileSystem::disk_initialize() {
benglish6	0:c69af1faeb95	198
benglish6	0:c69af1faeb95	199	int i = initialise_card();
benglish6	0:c69af1faeb95	200	// printf("init card = %d\n", i);
benglish6	0:c69af1faeb95	201	// printf("OK\n");
benglish6	0:c69af1faeb95	202
benglish6	0:c69af1faeb95	203	_sectors = _sd_sectors();
benglish6	0:c69af1faeb95	204
benglish6	0:c69af1faeb95	205	// Set block length to 512 (CMD16)
benglish6	0:c69af1faeb95	206	if(_cmd(16, 512) != 0) {
benglish6	0:c69af1faeb95	207	fprintf(stderr, "Set 512-byte block timed out\n");
benglish6	0:c69af1faeb95	208	return 1;
benglish6	0:c69af1faeb95	209	}
benglish6	0:c69af1faeb95	210
benglish6	0:c69af1faeb95	211	_spi.frequency(1000000); // Set to 1MHz for data transfer
benglish6	0:c69af1faeb95	212	return 0;
benglish6	0:c69af1faeb95	213	}
benglish6	0:c69af1faeb95	214
benglish6	0:c69af1faeb95	215	int SDFileSystem::disk_write(const char *buffer, int block_number) {
benglish6	0:c69af1faeb95	216	// set write address for single block (CMD24)
benglish6	0:c69af1faeb95	217	if(_cmd(24, block_number * 512) != 0) {
benglish6	0:c69af1faeb95	218	return 1;
benglish6	0:c69af1faeb95	219	}
benglish6	0:c69af1faeb95	220
benglish6	0:c69af1faeb95	221	// send the data block
benglish6	0:c69af1faeb95	222	_write(buffer, 512);
benglish6	0:c69af1faeb95	223	return 0;
benglish6	0:c69af1faeb95	224	}
benglish6	0:c69af1faeb95	225
benglish6	0:c69af1faeb95	226	int SDFileSystem::disk_read(char *buffer, int block_number) {
benglish6	0:c69af1faeb95	227	// set read address for single block (CMD17)
benglish6	0:c69af1faeb95	228	if(_cmd(17, block_number * 512) != 0) {
benglish6	0:c69af1faeb95	229	return 1;
benglish6	0:c69af1faeb95	230	}
benglish6	0:c69af1faeb95	231
benglish6	0:c69af1faeb95	232	// receive the data
benglish6	0:c69af1faeb95	233	_read(buffer, 512);
benglish6	0:c69af1faeb95	234	return 0;
benglish6	0:c69af1faeb95	235	}
benglish6	0:c69af1faeb95	236
benglish6	0:c69af1faeb95	237	int SDFileSystem::disk_status() { return 0; }
benglish6	0:c69af1faeb95	238	int SDFileSystem::disk_sync() { return 0; }
benglish6	0:c69af1faeb95	239	int SDFileSystem::disk_sectors() { return _sectors; }
benglish6	0:c69af1faeb95	240
benglish6	0:c69af1faeb95	241	// PRIVATE FUNCTIONS
benglish6	0:c69af1faeb95	242
benglish6	0:c69af1faeb95	243	int SDFileSystem::_cmd(int cmd, int arg) {
benglish6	0:c69af1faeb95	244	_cs = 0;
benglish6	0:c69af1faeb95	245
benglish6	0:c69af1faeb95	246	// send a command
benglish6	0:c69af1faeb95	247	_spi.write(0x40 \| cmd);
benglish6	0:c69af1faeb95	248	_spi.write(arg >> 24);
benglish6	0:c69af1faeb95	249	_spi.write(arg >> 16);
benglish6	0:c69af1faeb95	250	_spi.write(arg >> 8);
benglish6	0:c69af1faeb95	251	_spi.write(arg >> 0);
benglish6	0:c69af1faeb95	252	_spi.write(0x95);
benglish6	0:c69af1faeb95	253
benglish6	0:c69af1faeb95	254	// wait for the repsonse (response[7] == 0)
benglish6	0:c69af1faeb95	255	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
benglish6	0:c69af1faeb95	256	int response = _spi.write(0xFF);
benglish6	0:c69af1faeb95	257	if(!(response & 0x80)) {
benglish6	0:c69af1faeb95	258	_cs = 1;
benglish6	0:c69af1faeb95	259	_spi.write(0xFF);
benglish6	0:c69af1faeb95	260	return response;
benglish6	0:c69af1faeb95	261	}
benglish6	0:c69af1faeb95	262	}
benglish6	0:c69af1faeb95	263	_cs = 1;
benglish6	0:c69af1faeb95	264	_spi.write(0xFF);
benglish6	0:c69af1faeb95	265	return -1; // timeout
benglish6	0:c69af1faeb95	266	}
benglish6	0:c69af1faeb95	267	int SDFileSystem::_cmdx(int cmd, int arg) {
benglish6	0:c69af1faeb95	268	_cs = 0;
benglish6	0:c69af1faeb95	269
benglish6	0:c69af1faeb95	270	// send a command
benglish6	0:c69af1faeb95	271	_spi.write(0x40 \| cmd);
benglish6	0:c69af1faeb95	272	_spi.write(arg >> 24);
benglish6	0:c69af1faeb95	273	_spi.write(arg >> 16);
benglish6	0:c69af1faeb95	274	_spi.write(arg >> 8);
benglish6	0:c69af1faeb95	275	_spi.write(arg >> 0);
benglish6	0:c69af1faeb95	276	_spi.write(0x95);
benglish6	0:c69af1faeb95	277
benglish6	0:c69af1faeb95	278	// wait for the repsonse (response[7] == 0)
benglish6	0:c69af1faeb95	279	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
benglish6	0:c69af1faeb95	280	int response = _spi.write(0xFF);
benglish6	0:c69af1faeb95	281	if(!(response & 0x80)) {
benglish6	0:c69af1faeb95	282	return response;
benglish6	0:c69af1faeb95	283	}
benglish6	0:c69af1faeb95	284	}
benglish6	0:c69af1faeb95	285	_cs = 1;
benglish6	0:c69af1faeb95	286	_spi.write(0xFF);
benglish6	0:c69af1faeb95	287	return -1; // timeout
benglish6	0:c69af1faeb95	288	}
benglish6	0:c69af1faeb95	289
benglish6	0:c69af1faeb95	290
benglish6	0:c69af1faeb95	291	int SDFileSystem::_cmd58() {
benglish6	0:c69af1faeb95	292	_cs = 0;
benglish6	0:c69af1faeb95	293	int arg = 0;
benglish6	0:c69af1faeb95	294
benglish6	0:c69af1faeb95	295	// send a command
benglish6	0:c69af1faeb95	296	_spi.write(0x40 \| 58);
benglish6	0:c69af1faeb95	297	_spi.write(arg >> 24);
benglish6	0:c69af1faeb95	298	_spi.write(arg >> 16);
benglish6	0:c69af1faeb95	299	_spi.write(arg >> 8);
benglish6	0:c69af1faeb95	300	_spi.write(arg >> 0);
benglish6	0:c69af1faeb95	301	_spi.write(0x95);
benglish6	0:c69af1faeb95	302
benglish6	0:c69af1faeb95	303	// wait for the repsonse (response[7] == 0)
benglish6	0:c69af1faeb95	304	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
benglish6	0:c69af1faeb95	305	int response = _spi.write(0xFF);
benglish6	0:c69af1faeb95	306	if(!(response & 0x80)) {
benglish6	0:c69af1faeb95	307	int ocr = _spi.write(0xFF) << 24;
benglish6	0:c69af1faeb95	308	ocr \|= _spi.write(0xFF) << 16;
benglish6	0:c69af1faeb95	309	ocr \|= _spi.write(0xFF) << 8;
benglish6	0:c69af1faeb95	310	ocr \|= _spi.write(0xFF) << 0;
benglish6	0:c69af1faeb95	311	// printf("OCR = 0x%08X\n", ocr);
benglish6	0:c69af1faeb95	312	_cs = 1;
benglish6	0:c69af1faeb95	313	_spi.write(0xFF);
benglish6	0:c69af1faeb95	314	return response;
benglish6	0:c69af1faeb95	315	}
benglish6	0:c69af1faeb95	316	}
benglish6	0:c69af1faeb95	317	_cs = 1;
benglish6	0:c69af1faeb95	318	_spi.write(0xFF);
benglish6	0:c69af1faeb95	319	return -1; // timeout
benglish6	0:c69af1faeb95	320	}
benglish6	0:c69af1faeb95	321
benglish6	0:c69af1faeb95	322	int SDFileSystem::_cmd8() {
benglish6	0:c69af1faeb95	323	_cs = 0;
benglish6	0:c69af1faeb95	324
benglish6	0:c69af1faeb95	325	// send a command
benglish6	0:c69af1faeb95	326	_spi.write(0x40 \| 8); // CMD8
benglish6	0:c69af1faeb95	327	_spi.write(0x00); // reserved
benglish6	0:c69af1faeb95	328	_spi.write(0x00); // reserved
benglish6	0:c69af1faeb95	329	_spi.write(0x01); // 3.3v
benglish6	0:c69af1faeb95	330	_spi.write(0xAA); // check pattern
benglish6	0:c69af1faeb95	331	_spi.write(0x87); // crc
benglish6	0:c69af1faeb95	332
benglish6	0:c69af1faeb95	333	// wait for the repsonse (response[7] == 0)
benglish6	0:c69af1faeb95	334	for(int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) {
benglish6	0:c69af1faeb95	335	char response[5];
benglish6	0:c69af1faeb95	336	response[0] = _spi.write(0xFF);
benglish6	0:c69af1faeb95	337	if(!(response[0] & 0x80)) {
benglish6	0:c69af1faeb95	338	for(int j=1; j<5; j++) {
benglish6	0:c69af1faeb95	339	response[i] = _spi.write(0xFF);
benglish6	0:c69af1faeb95	340	}
benglish6	0:c69af1faeb95	341	_cs = 1;
benglish6	0:c69af1faeb95	342	_spi.write(0xFF);
benglish6	0:c69af1faeb95	343	return response[0];
benglish6	0:c69af1faeb95	344	}
benglish6	0:c69af1faeb95	345	}
benglish6	0:c69af1faeb95	346	_cs = 1;
benglish6	0:c69af1faeb95	347	_spi.write(0xFF);
benglish6	0:c69af1faeb95	348	return -1; // timeout
benglish6	0:c69af1faeb95	349	}
benglish6	0:c69af1faeb95	350
benglish6	0:c69af1faeb95	351	int SDFileSystem::_read(char *buffer, int length) {
benglish6	0:c69af1faeb95	352	_cs = 0;
benglish6	0:c69af1faeb95	353
benglish6	0:c69af1faeb95	354	// read until start byte (0xFF)
benglish6	0:c69af1faeb95	355	while(_spi.write(0xFF) != 0xFE);
benglish6	0:c69af1faeb95	356
benglish6	0:c69af1faeb95	357	// read data
benglish6	0:c69af1faeb95	358	for(int i=0; i<length; i++) {
benglish6	0:c69af1faeb95	359	buffer[i] = _spi.write(0xFF);
benglish6	0:c69af1faeb95	360	}
benglish6	0:c69af1faeb95	361	_spi.write(0xFF); // checksum
benglish6	0:c69af1faeb95	362	_spi.write(0xFF);
benglish6	0:c69af1faeb95	363
benglish6	0:c69af1faeb95	364	_cs = 1;
benglish6	0:c69af1faeb95	365	_spi.write(0xFF);
benglish6	0:c69af1faeb95	366	return 0;
benglish6	0:c69af1faeb95	367	}
benglish6	0:c69af1faeb95	368
benglish6	0:c69af1faeb95	369	int SDFileSystem::_write(const char *buffer, int length) {
benglish6	0:c69af1faeb95	370	_cs = 0;
benglish6	0:c69af1faeb95	371
benglish6	0:c69af1faeb95	372	// indicate start of block
benglish6	0:c69af1faeb95	373	_spi.write(0xFE);
benglish6	0:c69af1faeb95	374
benglish6	0:c69af1faeb95	375	// write the data
benglish6	0:c69af1faeb95	376	for(int i=0; i<length; i++) {
benglish6	0:c69af1faeb95	377	_spi.write(buffer[i]);
benglish6	0:c69af1faeb95	378	}
benglish6	0:c69af1faeb95	379
benglish6	0:c69af1faeb95	380	// write the checksum
benglish6	0:c69af1faeb95	381	_spi.write(0xFF);
benglish6	0:c69af1faeb95	382	_spi.write(0xFF);
benglish6	0:c69af1faeb95	383
benglish6	0:c69af1faeb95	384	// check the repsonse token
benglish6	0:c69af1faeb95	385	if((_spi.write(0xFF) & 0x1F) != 0x05) {
benglish6	0:c69af1faeb95	386	_cs = 1;
benglish6	0:c69af1faeb95	387	_spi.write(0xFF);
benglish6	0:c69af1faeb95	388	return 1;
benglish6	0:c69af1faeb95	389	}
benglish6	0:c69af1faeb95	390
benglish6	0:c69af1faeb95	391	// wait for write to finish
benglish6	0:c69af1faeb95	392	while(_spi.write(0xFF) == 0);
benglish6	0:c69af1faeb95	393
benglish6	0:c69af1faeb95	394	_cs = 1;
benglish6	0:c69af1faeb95	395	_spi.write(0xFF);
benglish6	0:c69af1faeb95	396	return 0;
benglish6	0:c69af1faeb95	397	}
benglish6	0:c69af1faeb95	398
benglish6	0:c69af1faeb95	399	static int ext_bits(char *data, int msb, int lsb) {
benglish6	0:c69af1faeb95	400	int bits = 0;
benglish6	0:c69af1faeb95	401	int size = 1 + msb - lsb;
benglish6	0:c69af1faeb95	402	for(int i=0; i<size; i++) {
benglish6	0:c69af1faeb95	403	int position = lsb + i;
benglish6	0:c69af1faeb95	404	int byte = 15 - (position >> 3);
benglish6	0:c69af1faeb95	405	int bit = position & 0x7;
benglish6	0:c69af1faeb95	406	int value = (data[byte] >> bit) & 1;
benglish6	0:c69af1faeb95	407	bits \|= value << i;
benglish6	0:c69af1faeb95	408	}
benglish6	0:c69af1faeb95	409	return bits;
benglish6	0:c69af1faeb95	410	}
benglish6	0:c69af1faeb95	411
benglish6	0:c69af1faeb95	412	int SDFileSystem::_sd_sectors() {
benglish6	0:c69af1faeb95	413
benglish6	0:c69af1faeb95	414	// CMD9, Response R2 (R1 byte + 16-byte block read)
benglish6	0:c69af1faeb95	415	if(_cmdx(9, 0) != 0) {
benglish6	0:c69af1faeb95	416	fprintf(stderr, "Didn't get a response from the disk\n");
benglish6	0:c69af1faeb95	417	return 0;
benglish6	0:c69af1faeb95	418	}
benglish6	0:c69af1faeb95	419
benglish6	0:c69af1faeb95	420	char csd[16];
benglish6	0:c69af1faeb95	421	if(_read(csd, 16) != 0) {
benglish6	0:c69af1faeb95	422	fprintf(stderr, "Couldn't read csd response from disk\n");
benglish6	0:c69af1faeb95	423	return 0;
benglish6	0:c69af1faeb95	424	}
benglish6	0:c69af1faeb95	425
benglish6	0:c69af1faeb95	426	// csd_structure : csd[127:126]
benglish6	0:c69af1faeb95	427	// c_size : csd[73:62]
benglish6	0:c69af1faeb95	428	// c_size_mult : csd[49:47]
benglish6	0:c69af1faeb95	429	// read_bl_len : csd[83:80] - the maximum read block length
benglish6	0:c69af1faeb95	430
benglish6	0:c69af1faeb95	431	int csd_structure = ext_bits(csd, 127, 126);
benglish6	0:c69af1faeb95	432	int c_size = ext_bits(csd, 73, 62);
benglish6	0:c69af1faeb95	433	int c_size_mult = ext_bits(csd, 49, 47);
benglish6	0:c69af1faeb95	434	int read_bl_len = ext_bits(csd, 83, 80);
benglish6	0:c69af1faeb95	435
benglish6	0:c69af1faeb95	436	// printf("CSD_STRUCT = %d\n", csd_structure);
benglish6	0:c69af1faeb95	437
benglish6	0:c69af1faeb95	438	if(csd_structure != 0) {
benglish6	0:c69af1faeb95	439	fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures\n");
benglish6	0:c69af1faeb95	440	return 0;
benglish6	0:c69af1faeb95	441	}
benglish6	0:c69af1faeb95	442
benglish6	0:c69af1faeb95	443	// memory capacity = BLOCKNR * BLOCK_LEN
benglish6	0:c69af1faeb95	444	// where
benglish6	0:c69af1faeb95	445	// BLOCKNR = (C_SIZE+1) * MULT
benglish6	0:c69af1faeb95	446	// MULT = 2^(C_SIZE_MULT+2) (C_SIZE_MULT < 8)
benglish6	0:c69af1faeb95	447	// BLOCK_LEN = 2^READ_BL_LEN, (READ_BL_LEN < 12)
benglish6	0:c69af1faeb95	448
benglish6	0:c69af1faeb95	449	int block_len = 1 << read_bl_len;
benglish6	0:c69af1faeb95	450	int mult = 1 << (c_size_mult + 2);
benglish6	0:c69af1faeb95	451	int blocknr = (c_size + 1) * mult;
benglish6	0:c69af1faeb95	452	int capacity = blocknr * block_len;
benglish6	0:c69af1faeb95	453
benglish6	0:c69af1faeb95	454	int blocks = capacity / 512;
benglish6	0:c69af1faeb95	455
benglish6	0:c69af1faeb95	456	return blocks;
benglish6	0:c69af1faeb95	457	}

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	28 Feb 2011
Imports:	37
Forks:	0
Commits:	2
Dependents:	0
Dependencies:	5
Followers:	1

SDFileSystem.cpp@0:c69af1faeb95, 2011-02-28 (annotated)

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