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Stephane ROCHON / Mbed 2 deprecated WAVEplayer

SDFileSystem.cpp@0:4cda52c0c66e, 2010-01-02 (annotated)

Committer:: Kerpower
Date:: Sat Jan 02 17:07:38 2010 +0000
Revision:: 0:4cda52c0c66e

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User	Revision	Line number	New contents of line
Kerpower	0:4cda52c0c66e	1	/* mbed Microcontroller Library - SDFileSystem
Kerpower	0:4cda52c0c66e	2	* Copyright (c) 2008-2009, sford
Kerpower	0:4cda52c0c66e	3	*
Kerpower	0:4cda52c0c66e	4	* Introduction
Kerpower	0:4cda52c0c66e	5	* ------------
Kerpower	0:4cda52c0c66e	6	* SD and MMC cards support a number of interfaces, but common to them all
Kerpower	0:4cda52c0c66e	7	* is one based on SPI. This is the one I'm implmenting because it means
Kerpower	0:4cda52c0c66e	8	* it is much more portable even though not so performant, and we already
Kerpower	0:4cda52c0c66e	9	* have the mbed SPI Interface!
Kerpower	0:4cda52c0c66e	10	*
Kerpower	0:4cda52c0c66e	11	* The main reference I'm using is Chapter 7, "SPI Mode" of:
Kerpower	0:4cda52c0c66e	12	* http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
Kerpower	0:4cda52c0c66e	13	*
Kerpower	0:4cda52c0c66e	14	* SPI Startup
Kerpower	0:4cda52c0c66e	15	* -----------
Kerpower	0:4cda52c0c66e	16	* The SD card powers up in SD mode. The SPI interface mode is selected by
Kerpower	0:4cda52c0c66e	17	* asserting CS low and sending the reset command (CMD0). The card will
Kerpower	0:4cda52c0c66e	18	* respond with a (R1) response.
Kerpower	0:4cda52c0c66e	19	*
Kerpower	0:4cda52c0c66e	20	* CMD8 is optionally sent to determine the voltage range supported, and
Kerpower	0:4cda52c0c66e	21	* indirectly determine whether it is a version 1.x SD/non-SD card or
Kerpower	0:4cda52c0c66e	22	* version 2.x. I'll just ignore this for now.
Kerpower	0:4cda52c0c66e	23	*
Kerpower	0:4cda52c0c66e	24	* ACMD41 is repeatedly issued to initialise the card, until "in idle"
Kerpower	0:4cda52c0c66e	25	* (bit 0) of the R1 response goes to '0', indicating it is initialised.
Kerpower	0:4cda52c0c66e	26	*
Kerpower	0:4cda52c0c66e	27	* You should also indicate whether the host supports High Capicity cards,
Kerpower	0:4cda52c0c66e	28	* and check whether the card is high capacity - i'll also ignore this
Kerpower	0:4cda52c0c66e	29	*
Kerpower	0:4cda52c0c66e	30	* SPI Protocol
Kerpower	0:4cda52c0c66e	31	* ------------
Kerpower	0:4cda52c0c66e	32	* The SD SPI protocol is based on transactions made up of 8-bit words, with
Kerpower	0:4cda52c0c66e	33	* the host starting every bus transaction by asserting the CS signal low. The
Kerpower	0:4cda52c0c66e	34	* card always responds to commands, data blocks and errors.
Kerpower	0:4cda52c0c66e	35	*
Kerpower	0:4cda52c0c66e	36	* The protocol supports a CRC, but by default it is off (except for the
Kerpower	0:4cda52c0c66e	37	* first reset CMD0, where the CRC can just be pre-calculated, and CMD8)
Kerpower	0:4cda52c0c66e	38	* I'll leave the CRC off I think!
Kerpower	0:4cda52c0c66e	39	*
Kerpower	0:4cda52c0c66e	40	* Standard capacity cards have variable data block sizes, whereas High
Kerpower	0:4cda52c0c66e	41	* Capacity cards fix the size of data block to 512 bytes. I'll therefore
Kerpower	0:4cda52c0c66e	42	* just always use the Standard Capacity cards with a block size of 512 bytes.
Kerpower	0:4cda52c0c66e	43	* This is set with CMD16.
Kerpower	0:4cda52c0c66e	44	*
Kerpower	0:4cda52c0c66e	45	* You can read and write single blocks (CMD17, CMD25) or multiple blocks
Kerpower	0:4cda52c0c66e	46	* (CMD18, CMD25). For simplicity, I'll just use single block accesses. When
Kerpower	0:4cda52c0c66e	47	* the card gets a read command, it responds with a response token, and then
Kerpower	0:4cda52c0c66e	48	* a data token or an error.
Kerpower	0:4cda52c0c66e	49	*
Kerpower	0:4cda52c0c66e	50	* SPI Command Format
Kerpower	0:4cda52c0c66e	51	* ------------------
Kerpower	0:4cda52c0c66e	52	* Commands are 6-bytes long, containing the command, 32-bit argument, and CRC.
Kerpower	0:4cda52c0c66e	53	*
Kerpower	0:4cda52c0c66e	54	* +---------------+------------+------------+-----------+----------+--------------+
Kerpower	0:4cda52c0c66e	55	* \| 01 \| cmd[5:0] \| arg[31:24] \| arg[23:16] \| arg[15:8] \| arg[7:0] \| crc[6:0] \| 1 \|
Kerpower	0:4cda52c0c66e	56	* +---------------+------------+------------+-----------+----------+--------------+
Kerpower	0:4cda52c0c66e	57	*
Kerpower	0:4cda52c0c66e	58	* As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95)
Kerpower	0:4cda52c0c66e	59	*
Kerpower	0:4cda52c0c66e	60	* All Application Specific commands shall be preceded with APP_CMD (CMD55).
Kerpower	0:4cda52c0c66e	61	*
Kerpower	0:4cda52c0c66e	62	* SPI Response Format
Kerpower	0:4cda52c0c66e	63	* -------------------
Kerpower	0:4cda52c0c66e	64	* The main response format (R1) is a status byte (normally zero). Key flags:
Kerpower	0:4cda52c0c66e	65	* idle - 1 if the card is in an idle state/initialising
Kerpower	0:4cda52c0c66e	66	* cmd - 1 if an illegal command code was detected
Kerpower	0:4cda52c0c66e	67	*
Kerpower	0:4cda52c0c66e	68	* +-------------------------------------------------+
Kerpower	0:4cda52c0c66e	69	* R1 \| 0 \| arg \| addr \| seq \| crc \| cmd \| erase \| idle \|
Kerpower	0:4cda52c0c66e	70	* +-------------------------------------------------+
Kerpower	0:4cda52c0c66e	71	*
Kerpower	0:4cda52c0c66e	72	* R1b is the same, except it is followed by a busy signal (zeros) until
Kerpower	0:4cda52c0c66e	73	* the first non-zero byte when it is ready again.
Kerpower	0:4cda52c0c66e	74	*
Kerpower	0:4cda52c0c66e	75	* Data Response Token
Kerpower	0:4cda52c0c66e	76	* -------------------
Kerpower	0:4cda52c0c66e	77	* Every data block written to the card is acknowledged by a byte
Kerpower	0:4cda52c0c66e	78	* response token
Kerpower	0:4cda52c0c66e	79	*
Kerpower	0:4cda52c0c66e	80	* +----------------------+
Kerpower	0:4cda52c0c66e	81	* \| xxx \| 0 \| status \| 1 \|
Kerpower	0:4cda52c0c66e	82	* +----------------------+
Kerpower	0:4cda52c0c66e	83	* 010 - OK!
Kerpower	0:4cda52c0c66e	84	* 101 - CRC Error
Kerpower	0:4cda52c0c66e	85	* 110 - Write Error
Kerpower	0:4cda52c0c66e	86	*
Kerpower	0:4cda52c0c66e	87	* Single Block Read and Write
Kerpower	0:4cda52c0c66e	88	* ---------------------------
Kerpower	0:4cda52c0c66e	89	*
Kerpower	0:4cda52c0c66e	90	* Block transfers have a byte header, followed by the data, followed
Kerpower	0:4cda52c0c66e	91	* by a 16-bit CRC. In our case, the data will always be 512 bytes.
Kerpower	0:4cda52c0c66e	92	*
Kerpower	0:4cda52c0c66e	93	* +------+---------+---------+- - - -+---------+-----------+----------+
Kerpower	0:4cda52c0c66e	94	* \| 0xFE \| data[0] \| data[1] \| \| data[n] \| crc[15:8] \| crc[7:0] \|
Kerpower	0:4cda52c0c66e	95	* +------+---------+---------+- - - -+---------+-----------+----------+
Kerpower	0:4cda52c0c66e	96	*/
Kerpower	0:4cda52c0c66e	97
Kerpower	0:4cda52c0c66e	98	#include "SDFileSystem.h"
Kerpower	0:4cda52c0c66e	99
Kerpower	0:4cda52c0c66e	100	#define SD_COMMAND_TIMEOUT 5000
Kerpower	0:4cda52c0c66e	101
Kerpower	0:4cda52c0c66e	102	SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) :
Kerpower	0:4cda52c0c66e	103	FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) {
Kerpower	0:4cda52c0c66e	104	_cs = 1;
Kerpower	0:4cda52c0c66e	105	}
Kerpower	0:4cda52c0c66e	106
Kerpower	0:4cda52c0c66e	107	int SDFileSystem::disk_initialize() {
Kerpower	0:4cda52c0c66e	108
Kerpower	0:4cda52c0c66e	109	_spi.frequency(100000); // Set to 100kHz for initialisation
Kerpower	0:4cda52c0c66e	110
Kerpower	0:4cda52c0c66e	111	// Initialise the card by clocking it with cs = 1
Kerpower	0:4cda52c0c66e	112	_cs = 1;
Kerpower	0:4cda52c0c66e	113	for(int i=0; i<16; i++) {
Kerpower	0:4cda52c0c66e	114	_spi.write(0xFF);
Kerpower	0:4cda52c0c66e	115	}
Kerpower	0:4cda52c0c66e	116
Kerpower	0:4cda52c0c66e	117	// send CMD0, should return with all zeros except IDLE STATE set (bit 0)
Kerpower	0:4cda52c0c66e	118	if(_cmd(0, 0) != 0x01) {
Kerpower	0:4cda52c0c66e	119	fprintf(stderr, "Not in idle state\n");
Kerpower	0:4cda52c0c66e	120	return 1;
Kerpower	0:4cda52c0c66e	121	}
Kerpower	0:4cda52c0c66e	122
Kerpower	0:4cda52c0c66e	123	// ACMD41 to give host capacity support (repeat until not busy)
Kerpower	0:4cda52c0c66e	124	// ACMD41 is application specific command, so we send APP_CMD (CMD55) beforehand
Kerpower	0:4cda52c0c66e	125	for(int i=0;; i++) {
Kerpower	0:4cda52c0c66e	126	_cmd(55, 0);
Kerpower	0:4cda52c0c66e	127	int response = _cmd(41, 0);
Kerpower	0:4cda52c0c66e	128	if(response == 0) {
Kerpower	0:4cda52c0c66e	129	break;
Kerpower	0:4cda52c0c66e	130	} else if(i > SD_COMMAND_TIMEOUT) {
Kerpower	0:4cda52c0c66e	131	fprintf(stderr, "Timeout waiting for card\n");
Kerpower	0:4cda52c0c66e	132	return 1;
Kerpower	0:4cda52c0c66e	133	}
Kerpower	0:4cda52c0c66e	134	}
Kerpower	0:4cda52c0c66e	135
Kerpower	0:4cda52c0c66e	136	_sectors = _sd_sectors();
Kerpower	0:4cda52c0c66e	137
Kerpower	0:4cda52c0c66e	138	// Set block length to 512 (CMD16)
Kerpower	0:4cda52c0c66e	139	if(_cmd(16, 512) != 0) {
Kerpower	0:4cda52c0c66e	140	fprintf(stderr, "Set block timeout\n");
Kerpower	0:4cda52c0c66e	141	return 1;
Kerpower	0:4cda52c0c66e	142	}
Kerpower	0:4cda52c0c66e	143
Kerpower	0:4cda52c0c66e	144	_spi.frequency(1000000); // Set to 1MHz for data transfer
Kerpower	0:4cda52c0c66e	145	return 0;
Kerpower	0:4cda52c0c66e	146	}
Kerpower	0:4cda52c0c66e	147
Kerpower	0:4cda52c0c66e	148	int SDFileSystem::disk_write(const char *buffer, int block_number) {
Kerpower	0:4cda52c0c66e	149	// set write address for single block (CMD24)
Kerpower	0:4cda52c0c66e	150	if(_cmd(24, block_number * 512) != 0) {
Kerpower	0:4cda52c0c66e	151	return 1;
Kerpower	0:4cda52c0c66e	152	}
Kerpower	0:4cda52c0c66e	153
Kerpower	0:4cda52c0c66e	154	// send the data block
Kerpower	0:4cda52c0c66e	155	_write(buffer, 512);
Kerpower	0:4cda52c0c66e	156	return 0;
Kerpower	0:4cda52c0c66e	157	}
Kerpower	0:4cda52c0c66e	158
Kerpower	0:4cda52c0c66e	159	int SDFileSystem::disk_read(char *buffer, int block_number) {
Kerpower	0:4cda52c0c66e	160	// set read address for single block (CMD17)
Kerpower	0:4cda52c0c66e	161	if(_cmd(17, block_number * 512) != 0) {
Kerpower	0:4cda52c0c66e	162	return 1;
Kerpower	0:4cda52c0c66e	163	}
Kerpower	0:4cda52c0c66e	164
Kerpower	0:4cda52c0c66e	165	// receive the data
Kerpower	0:4cda52c0c66e	166	_read(buffer, 512);
Kerpower	0:4cda52c0c66e	167	return 0;
Kerpower	0:4cda52c0c66e	168	}
Kerpower	0:4cda52c0c66e	169
Kerpower	0:4cda52c0c66e	170	int SDFileSystem::disk_status() { return 0; }
Kerpower	0:4cda52c0c66e	171	int SDFileSystem::disk_sync() { return 0; }
Kerpower	0:4cda52c0c66e	172	int SDFileSystem::disk_sectors() { return _sectors; }
Kerpower	0:4cda52c0c66e	173
Kerpower	0:4cda52c0c66e	174	// PRIVATE FUNCTIONS
Kerpower	0:4cda52c0c66e	175
Kerpower	0:4cda52c0c66e	176	int SDFileSystem::_cmd(int cmd, int arg) {
Kerpower	0:4cda52c0c66e	177	_cs = 0;
Kerpower	0:4cda52c0c66e	178
Kerpower	0:4cda52c0c66e	179	// send a command
Kerpower	0:4cda52c0c66e	180	_spi.write(0x40 \| cmd);
Kerpower	0:4cda52c0c66e	181	_spi.write(arg >> 24);
Kerpower	0:4cda52c0c66e	182	_spi.write(arg >> 16);
Kerpower	0:4cda52c0c66e	183	_spi.write(arg >> 8);
Kerpower	0:4cda52c0c66e	184	_spi.write(arg >> 0);
Kerpower	0:4cda52c0c66e	185	_spi.write(0x95);
Kerpower	0:4cda52c0c66e	186
Kerpower	0:4cda52c0c66e	187	// wait for the repsonse (response[7] == 0)
Kerpower	0:4cda52c0c66e	188	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
Kerpower	0:4cda52c0c66e	189	int response = _spi.write(0xFF);
Kerpower	0:4cda52c0c66e	190	if(!(response & 0x80)) {
Kerpower	0:4cda52c0c66e	191	_cs = 1;
Kerpower	0:4cda52c0c66e	192	_spi.write(0xFF);
Kerpower	0:4cda52c0c66e	193	return response;
Kerpower	0:4cda52c0c66e	194	}
Kerpower	0:4cda52c0c66e	195	}
Kerpower	0:4cda52c0c66e	196	_cs = 1;
Kerpower	0:4cda52c0c66e	197	_spi.write(0xFF);
Kerpower	0:4cda52c0c66e	198	return -1; // timeout
Kerpower	0:4cda52c0c66e	199	}
Kerpower	0:4cda52c0c66e	200
Kerpower	0:4cda52c0c66e	201	int SDFileSystem::_read(char *buffer, int length) {
Kerpower	0:4cda52c0c66e	202	_cs = 0;
Kerpower	0:4cda52c0c66e	203
Kerpower	0:4cda52c0c66e	204	// read until start byte (0xFF)
Kerpower	0:4cda52c0c66e	205	while(_spi.write(0xFF) != 0xFE);
Kerpower	0:4cda52c0c66e	206
Kerpower	0:4cda52c0c66e	207	// read data
Kerpower	0:4cda52c0c66e	208	for(int i=0; i<length; i++) {
Kerpower	0:4cda52c0c66e	209	buffer[i] = _spi.write(0xFF);
Kerpower	0:4cda52c0c66e	210	}
Kerpower	0:4cda52c0c66e	211	_spi.write(0xFF); // checksum
Kerpower	0:4cda52c0c66e	212	_spi.write(0xFF);
Kerpower	0:4cda52c0c66e	213
Kerpower	0:4cda52c0c66e	214	_cs = 1;
Kerpower	0:4cda52c0c66e	215	_spi.write(0xFF);
Kerpower	0:4cda52c0c66e	216	return 0;
Kerpower	0:4cda52c0c66e	217	}
Kerpower	0:4cda52c0c66e	218
Kerpower	0:4cda52c0c66e	219	int SDFileSystem::_write(const char *buffer, int length) {
Kerpower	0:4cda52c0c66e	220	_cs = 0;
Kerpower	0:4cda52c0c66e	221
Kerpower	0:4cda52c0c66e	222	// indicate start of block
Kerpower	0:4cda52c0c66e	223	_spi.write(0xFE);
Kerpower	0:4cda52c0c66e	224
Kerpower	0:4cda52c0c66e	225	// write the data
Kerpower	0:4cda52c0c66e	226	for(int i=0; i<length; i++) {
Kerpower	0:4cda52c0c66e	227	_spi.write(buffer[i]);
Kerpower	0:4cda52c0c66e	228	}
Kerpower	0:4cda52c0c66e	229
Kerpower	0:4cda52c0c66e	230	// write the checksum
Kerpower	0:4cda52c0c66e	231	_spi.write(0xFF);
Kerpower	0:4cda52c0c66e	232	_spi.write(0xFF);
Kerpower	0:4cda52c0c66e	233
Kerpower	0:4cda52c0c66e	234	// check the repsonse token
Kerpower	0:4cda52c0c66e	235	if((_spi.write(0xFF) & 0x1F) != 0x05) {
Kerpower	0:4cda52c0c66e	236	_cs = 1;
Kerpower	0:4cda52c0c66e	237	_spi.write(0xFF);
Kerpower	0:4cda52c0c66e	238	return 1;
Kerpower	0:4cda52c0c66e	239	}
Kerpower	0:4cda52c0c66e	240
Kerpower	0:4cda52c0c66e	241	// wait for write to finish
Kerpower	0:4cda52c0c66e	242	while(_spi.write(0xFF) == 0);
Kerpower	0:4cda52c0c66e	243
Kerpower	0:4cda52c0c66e	244	_cs = 1;
Kerpower	0:4cda52c0c66e	245	_spi.write(0xFF);
Kerpower	0:4cda52c0c66e	246	return 0;
Kerpower	0:4cda52c0c66e	247	}
Kerpower	0:4cda52c0c66e	248
Kerpower	0:4cda52c0c66e	249	static int ext_bits(char *data, int msb, int lsb) {
Kerpower	0:4cda52c0c66e	250	int bits = 0;
Kerpower	0:4cda52c0c66e	251	int size = 1 + msb - lsb;
Kerpower	0:4cda52c0c66e	252	for(int i=0; i<size; i++) {
Kerpower	0:4cda52c0c66e	253	int position = lsb + i;
Kerpower	0:4cda52c0c66e	254	int byte = 15 - (position >> 3);
Kerpower	0:4cda52c0c66e	255	int bit = position & 0x7;
Kerpower	0:4cda52c0c66e	256	int value = (data[byte] >> bit) & 1;
Kerpower	0:4cda52c0c66e	257	bits \|= value << i;
Kerpower	0:4cda52c0c66e	258	}
Kerpower	0:4cda52c0c66e	259	return bits;
Kerpower	0:4cda52c0c66e	260	}
Kerpower	0:4cda52c0c66e	261
Kerpower	0:4cda52c0c66e	262	int SDFileSystem::_sd_sectors() {
Kerpower	0:4cda52c0c66e	263
Kerpower	0:4cda52c0c66e	264	// CMD9, Response R2 (R1 byte + 16-byte block read)
Kerpower	0:4cda52c0c66e	265	if(_cmd(9, 0) != 0) {
Kerpower	0:4cda52c0c66e	266	fprintf(stderr, "Didn't get a response from the disk\n");
Kerpower	0:4cda52c0c66e	267	return 0;
Kerpower	0:4cda52c0c66e	268	}
Kerpower	0:4cda52c0c66e	269
Kerpower	0:4cda52c0c66e	270	char csd[16];
Kerpower	0:4cda52c0c66e	271	if(_read(csd, 16) != 0) {
Kerpower	0:4cda52c0c66e	272	fprintf(stderr, "Couldn't read csd response from disk\n");
Kerpower	0:4cda52c0c66e	273	return 0;
Kerpower	0:4cda52c0c66e	274	}
Kerpower	0:4cda52c0c66e	275
Kerpower	0:4cda52c0c66e	276	// csd_structure : csd[127:126]
Kerpower	0:4cda52c0c66e	277	// c_size : csd[73:62]
Kerpower	0:4cda52c0c66e	278	// c_size_mult : csd[49:47]
Kerpower	0:4cda52c0c66e	279	// read_bl_len : csd[83:80]
Kerpower	0:4cda52c0c66e	280
Kerpower	0:4cda52c0c66e	281	int csd_structure = ext_bits(csd, 127, 126);
Kerpower	0:4cda52c0c66e	282	int c_size = ext_bits(csd, 73, 62);
Kerpower	0:4cda52c0c66e	283	int c_size_mult = ext_bits(csd, 49, 47);
Kerpower	0:4cda52c0c66e	284	int read_bl_len = ext_bits(csd, 83, 80);
Kerpower	0:4cda52c0c66e	285
Kerpower	0:4cda52c0c66e	286	if(csd_structure != 0) {
Kerpower	0:4cda52c0c66e	287	fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures");
Kerpower	0:4cda52c0c66e	288	return 0;
Kerpower	0:4cda52c0c66e	289	}
Kerpower	0:4cda52c0c66e	290
Kerpower	0:4cda52c0c66e	291	int blocks = (c_size + 1) * (1 << (c_size_mult + 2));
Kerpower	0:4cda52c0c66e	292	int block_size = 1 << read_bl_len;
Kerpower	0:4cda52c0c66e	293
Kerpower	0:4cda52c0c66e	294	if(block_size != 512) {
Kerpower	0:4cda52c0c66e	295	fprintf(stderr, "This disk tastes funny! I only like 512-byte blocks");
Kerpower	0:4cda52c0c66e	296	return 0;
Kerpower	0:4cda52c0c66e	297	}
Kerpower	0:4cda52c0c66e	298
Kerpower	0:4cda52c0c66e	299	return blocks;
Kerpower	0:4cda52c0c66e	300	}

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	02 Jan 2010
Imports:	42
Forks:	1
Commits:	1
Dependents:	0
Dependencies:	1
Followers:	1

SDFileSystem.cpp@0:4cda52c0c66e, 2010-01-02 (annotated)

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