DataLogIMU-BARO - interface to chr_6dm and Baro bmp085

Users » belloula » Code » DataLogIMU-BARO

Abdelmalek BELLOULA / Mbed 2 deprecated DataLogIMU-BARO

interface to chr_6dm and Baro bmp085

SDFileSystem.cpp@0:d07617f8ede9, 2011-10-17 (annotated)

Committer:: belloula
Date:: Mon Oct 17 19:43:06 2011 +0000
Revision:: 0:d07617f8ede9

Who changed what in which revision?

User	Revision	Line number	New contents of line
belloula	0:d07617f8ede9	1	/* mbed SDFileSystem Library, for providing file access to SD cards
belloula	0:d07617f8ede9	2	* Copyright (c) 2008-2010, sford
belloula	0:d07617f8ede9	3	*
belloula	0:d07617f8ede9	4	* Permission is hereby granted, free of charge, to any person obtaining a copy
belloula	0:d07617f8ede9	5	* of this software and associated documentation files (the "Software"), to deal
belloula	0:d07617f8ede9	6	* in the Software without restriction, including without limitation the rights
belloula	0:d07617f8ede9	7	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
belloula	0:d07617f8ede9	8	* copies of the Software, and to permit persons to whom the Software is
belloula	0:d07617f8ede9	9	* furnished to do so, subject to the following conditions:
belloula	0:d07617f8ede9	10	*
belloula	0:d07617f8ede9	11	* The above copyright notice and this permission notice shall be included in
belloula	0:d07617f8ede9	12	* all copies or substantial portions of the Software.
belloula	0:d07617f8ede9	13	*
belloula	0:d07617f8ede9	14	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
belloula	0:d07617f8ede9	15	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
belloula	0:d07617f8ede9	16	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
belloula	0:d07617f8ede9	17	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
belloula	0:d07617f8ede9	18	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
belloula	0:d07617f8ede9	19	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
belloula	0:d07617f8ede9	20	* THE SOFTWARE.
belloula	0:d07617f8ede9	21	*/
belloula	0:d07617f8ede9	22
belloula	0:d07617f8ede9	23	/* Introduction
belloula	0:d07617f8ede9	24	* ------------
belloula	0:d07617f8ede9	25	* SD and MMC cards support a number of interfaces, but common to them all
belloula	0:d07617f8ede9	26	* is one based on SPI. This is the one I'm implmenting because it means
belloula	0:d07617f8ede9	27	* it is much more portable even though not so performant, and we already
belloula	0:d07617f8ede9	28	* have the mbed SPI Interface!
belloula	0:d07617f8ede9	29	*
belloula	0:d07617f8ede9	30	* The main reference I'm using is Chapter 7, "SPI Mode" of:
belloula	0:d07617f8ede9	31	* http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
belloula	0:d07617f8ede9	32	*
belloula	0:d07617f8ede9	33	* SPI Startup
belloula	0:d07617f8ede9	34	* -----------
belloula	0:d07617f8ede9	35	* The SD card powers up in SD mode. The SPI interface mode is selected by
belloula	0:d07617f8ede9	36	* asserting CS low and sending the reset command (CMD0). The card will
belloula	0:d07617f8ede9	37	* respond with a (R1) response.
belloula	0:d07617f8ede9	38	*
belloula	0:d07617f8ede9	39	* CMD8 is optionally sent to determine the voltage range supported, and
belloula	0:d07617f8ede9	40	* indirectly determine whether it is a version 1.x SD/non-SD card or
belloula	0:d07617f8ede9	41	* version 2.x. I'll just ignore this for now.
belloula	0:d07617f8ede9	42	*
belloula	0:d07617f8ede9	43	* ACMD41 is repeatedly issued to initialise the card, until "in idle"
belloula	0:d07617f8ede9	44	* (bit 0) of the R1 response goes to '0', indicating it is initialised.
belloula	0:d07617f8ede9	45	*
belloula	0:d07617f8ede9	46	* You should also indicate whether the host supports High Capicity cards,
belloula	0:d07617f8ede9	47	* and check whether the card is high capacity - i'll also ignore this
belloula	0:d07617f8ede9	48	*
belloula	0:d07617f8ede9	49	* SPI Protocol
belloula	0:d07617f8ede9	50	* ------------
belloula	0:d07617f8ede9	51	* The SD SPI protocol is based on transactions made up of 8-bit words, with
belloula	0:d07617f8ede9	52	* the host starting every bus transaction by asserting the CS signal low. The
belloula	0:d07617f8ede9	53	* card always responds to commands, data blocks and errors.
belloula	0:d07617f8ede9	54	*
belloula	0:d07617f8ede9	55	* The protocol supports a CRC, but by default it is off (except for the
belloula	0:d07617f8ede9	56	* first reset CMD0, where the CRC can just be pre-calculated, and CMD8)
belloula	0:d07617f8ede9	57	* I'll leave the CRC off I think!
belloula	0:d07617f8ede9	58	*
belloula	0:d07617f8ede9	59	* Standard capacity cards have variable data block sizes, whereas High
belloula	0:d07617f8ede9	60	* Capacity cards fix the size of data block to 512 bytes. I'll therefore
belloula	0:d07617f8ede9	61	* just always use the Standard Capacity cards with a block size of 512 bytes.
belloula	0:d07617f8ede9	62	* This is set with CMD16.
belloula	0:d07617f8ede9	63	*
belloula	0:d07617f8ede9	64	* You can read and write single blocks (CMD17, CMD25) or multiple blocks
belloula	0:d07617f8ede9	65	* (CMD18, CMD25). For simplicity, I'll just use single block accesses. When
belloula	0:d07617f8ede9	66	* the card gets a read command, it responds with a response token, and then
belloula	0:d07617f8ede9	67	* a data token or an error.
belloula	0:d07617f8ede9	68	*
belloula	0:d07617f8ede9	69	* SPI Command Format
belloula	0:d07617f8ede9	70	* ------------------
belloula	0:d07617f8ede9	71	* Commands are 6-bytes long, containing the command, 32-bit argument, and CRC.
belloula	0:d07617f8ede9	72	*
belloula	0:d07617f8ede9	73	* +---------------+------------+------------+-----------+----------+--------------+
belloula	0:d07617f8ede9	74	* \| 01 \| cmd[5:0] \| arg[31:24] \| arg[23:16] \| arg[15:8] \| arg[7:0] \| crc[6:0] \| 1 \|
belloula	0:d07617f8ede9	75	* +---------------+------------+------------+-----------+----------+--------------+
belloula	0:d07617f8ede9	76	*
belloula	0:d07617f8ede9	77	* As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95)
belloula	0:d07617f8ede9	78	*
belloula	0:d07617f8ede9	79	* All Application Specific commands shall be preceded with APP_CMD (CMD55).
belloula	0:d07617f8ede9	80	*
belloula	0:d07617f8ede9	81	* SPI Response Format
belloula	0:d07617f8ede9	82	* -------------------
belloula	0:d07617f8ede9	83	* The main response format (R1) is a status byte (normally zero). Key flags:
belloula	0:d07617f8ede9	84	* idle - 1 if the card is in an idle state/initialising
belloula	0:d07617f8ede9	85	* cmd - 1 if an illegal command code was detected
belloula	0:d07617f8ede9	86	*
belloula	0:d07617f8ede9	87	* +-------------------------------------------------+
belloula	0:d07617f8ede9	88	* R1 \| 0 \| arg \| addr \| seq \| crc \| cmd \| erase \| idle \|
belloula	0:d07617f8ede9	89	* +-------------------------------------------------+
belloula	0:d07617f8ede9	90	*
belloula	0:d07617f8ede9	91	* R1b is the same, except it is followed by a busy signal (zeros) until
belloula	0:d07617f8ede9	92	* the first non-zero byte when it is ready again.
belloula	0:d07617f8ede9	93	*
belloula	0:d07617f8ede9	94	* Data Response Token
belloula	0:d07617f8ede9	95	* -------------------
belloula	0:d07617f8ede9	96	* Every data block written to the card is acknowledged by a byte
belloula	0:d07617f8ede9	97	* response token
belloula	0:d07617f8ede9	98	*
belloula	0:d07617f8ede9	99	* +----------------------+
belloula	0:d07617f8ede9	100	* \| xxx \| 0 \| status \| 1 \|
belloula	0:d07617f8ede9	101	* +----------------------+
belloula	0:d07617f8ede9	102	* 010 - OK!
belloula	0:d07617f8ede9	103	* 101 - CRC Error
belloula	0:d07617f8ede9	104	* 110 - Write Error
belloula	0:d07617f8ede9	105	*
belloula	0:d07617f8ede9	106	* Single Block Read and Write
belloula	0:d07617f8ede9	107	* ---------------------------
belloula	0:d07617f8ede9	108	*
belloula	0:d07617f8ede9	109	* Block transfers have a byte header, followed by the data, followed
belloula	0:d07617f8ede9	110	* by a 16-bit CRC. In our case, the data will always be 512 bytes.
belloula	0:d07617f8ede9	111	*
belloula	0:d07617f8ede9	112	* +------+---------+---------+- - - -+---------+-----------+----------+
belloula	0:d07617f8ede9	113	* \| 0xFE \| data[0] \| data[1] \| \| data[n] \| crc[15:8] \| crc[7:0] \|
belloula	0:d07617f8ede9	114	* +------+---------+---------+- - - -+---------+-----------+----------+
belloula	0:d07617f8ede9	115	*/
belloula	0:d07617f8ede9	116
belloula	0:d07617f8ede9	117	#include "SDFileSystem.h"
belloula	0:d07617f8ede9	118
belloula	0:d07617f8ede9	119	#define SD_COMMAND_TIMEOUT 5000
belloula	0:d07617f8ede9	120
belloula	0:d07617f8ede9	121	SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) :
belloula	0:d07617f8ede9	122	FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) {
belloula	0:d07617f8ede9	123	_cs = 1;
belloula	0:d07617f8ede9	124	}
belloula	0:d07617f8ede9	125
belloula	0:d07617f8ede9	126	#define R1_IDLE_STATE (1 << 0)
belloula	0:d07617f8ede9	127	#define R1_ERASE_RESET (1 << 1)
belloula	0:d07617f8ede9	128	#define R1_ILLEGAL_COMMAND (1 << 2)
belloula	0:d07617f8ede9	129	#define R1_COM_CRC_ERROR (1 << 3)
belloula	0:d07617f8ede9	130	#define R1_ERASE_SEQUENCE_ERROR (1 << 4)
belloula	0:d07617f8ede9	131	#define R1_ADDRESS_ERROR (1 << 5)
belloula	0:d07617f8ede9	132	#define R1_PARAMETER_ERROR (1 << 6)
belloula	0:d07617f8ede9	133
belloula	0:d07617f8ede9	134	// Types
belloula	0:d07617f8ede9	135	// - v1.x Standard Capacity
belloula	0:d07617f8ede9	136	// - v2.x Standard Capacity
belloula	0:d07617f8ede9	137	// - v2.x High Capacity
belloula	0:d07617f8ede9	138	// - Not recognised as an SD Card
belloula	0:d07617f8ede9	139
belloula	0:d07617f8ede9	140	#define SDCARD_FAIL 0
belloula	0:d07617f8ede9	141	#define SDCARD_V1 1
belloula	0:d07617f8ede9	142	#define SDCARD_V2 2
belloula	0:d07617f8ede9	143	#define SDCARD_V2HC 3
belloula	0:d07617f8ede9	144
belloula	0:d07617f8ede9	145	int SDFileSystem::initialise_card() {
belloula	0:d07617f8ede9	146	// Set to 100kHz for initialisation, and clock card with cs = 1
belloula	0:d07617f8ede9	147	_spi.frequency(100000);
belloula	0:d07617f8ede9	148	_cs = 1;
belloula	0:d07617f8ede9	149	for(int i=0; i<16; i++) {
belloula	0:d07617f8ede9	150	_spi.write(0xFF);
belloula	0:d07617f8ede9	151	}
belloula	0:d07617f8ede9	152
belloula	0:d07617f8ede9	153	// send CMD0, should return with all zeros except IDLE STATE set (bit 0)
belloula	0:d07617f8ede9	154	if(_cmd(0, 0) != R1_IDLE_STATE) {
belloula	0:d07617f8ede9	155	fprintf(stderr, "No disk, or could not put SD card in to SPI idle state\n");
belloula	0:d07617f8ede9	156	return SDCARD_FAIL;
belloula	0:d07617f8ede9	157	}
belloula	0:d07617f8ede9	158
belloula	0:d07617f8ede9	159	// send CMD8 to determine whther it is ver 2.x
belloula	0:d07617f8ede9	160	int r = _cmd8();
belloula	0:d07617f8ede9	161	if(r == R1_IDLE_STATE) {
belloula	0:d07617f8ede9	162	return initialise_card_v2();
belloula	0:d07617f8ede9	163	} else if(r == (R1_IDLE_STATE \| R1_ILLEGAL_COMMAND)) {
belloula	0:d07617f8ede9	164	return initialise_card_v1();
belloula	0:d07617f8ede9	165	} else {
belloula	0:d07617f8ede9	166	fprintf(stderr, "Not in idle state after sending CMD8 (not an SD card?)\n");
belloula	0:d07617f8ede9	167	return SDCARD_FAIL;
belloula	0:d07617f8ede9	168	}
belloula	0:d07617f8ede9	169	}
belloula	0:d07617f8ede9	170
belloula	0:d07617f8ede9	171	int SDFileSystem::initialise_card_v1() {
belloula	0:d07617f8ede9	172	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
belloula	0:d07617f8ede9	173	_cmd(55, 0);
belloula	0:d07617f8ede9	174	if(_cmd(41, 0) == 0) {
belloula	0:d07617f8ede9	175	return SDCARD_V1;
belloula	0:d07617f8ede9	176	}
belloula	0:d07617f8ede9	177	}
belloula	0:d07617f8ede9	178
belloula	0:d07617f8ede9	179	fprintf(stderr, "Timeout waiting for v1.x card\n");
belloula	0:d07617f8ede9	180	return SDCARD_FAIL;
belloula	0:d07617f8ede9	181	}
belloula	0:d07617f8ede9	182
belloula	0:d07617f8ede9	183	int SDFileSystem::initialise_card_v2() {
belloula	0:d07617f8ede9	184
belloula	0:d07617f8ede9	185	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
belloula	0:d07617f8ede9	186	_cmd(55, 0);
belloula	0:d07617f8ede9	187	if(_cmd(41, 0) == 0) {
belloula	0:d07617f8ede9	188	_cmd58();
belloula	0:d07617f8ede9	189	return SDCARD_V2;
belloula	0:d07617f8ede9	190	}
belloula	0:d07617f8ede9	191	}
belloula	0:d07617f8ede9	192
belloula	0:d07617f8ede9	193	fprintf(stderr, "Timeout waiting for v2.x card\n");
belloula	0:d07617f8ede9	194	return SDCARD_FAIL;
belloula	0:d07617f8ede9	195	}
belloula	0:d07617f8ede9	196
belloula	0:d07617f8ede9	197	int SDFileSystem::disk_initialize() {
belloula	0:d07617f8ede9	198
belloula	0:d07617f8ede9	199	int i = initialise_card();
belloula	0:d07617f8ede9	200	// printf("init card = %d\n", i);
belloula	0:d07617f8ede9	201	// printf("OK\n");
belloula	0:d07617f8ede9	202
belloula	0:d07617f8ede9	203	_sectors = _sd_sectors();
belloula	0:d07617f8ede9	204
belloula	0:d07617f8ede9	205	// Set block length to 512 (CMD16)
belloula	0:d07617f8ede9	206	if(_cmd(16, 512) != 0) {
belloula	0:d07617f8ede9	207	fprintf(stderr, "Set 512-byte block timed out\n");
belloula	0:d07617f8ede9	208	return 1;
belloula	0:d07617f8ede9	209	}
belloula	0:d07617f8ede9	210
belloula	0:d07617f8ede9	211	_spi.frequency(1000000); // Set to 1MHz for data transfer
belloula	0:d07617f8ede9	212	return 0;
belloula	0:d07617f8ede9	213	}
belloula	0:d07617f8ede9	214
belloula	0:d07617f8ede9	215	int SDFileSystem::disk_write(const char *buffer, int block_number) {
belloula	0:d07617f8ede9	216	// set write address for single block (CMD24)
belloula	0:d07617f8ede9	217	if(_cmd(24, block_number * 512) != 0) {
belloula	0:d07617f8ede9	218	return 1;
belloula	0:d07617f8ede9	219	}
belloula	0:d07617f8ede9	220
belloula	0:d07617f8ede9	221	// send the data block
belloula	0:d07617f8ede9	222	_write(buffer, 512);
belloula	0:d07617f8ede9	223	return 0;
belloula	0:d07617f8ede9	224	}
belloula	0:d07617f8ede9	225
belloula	0:d07617f8ede9	226	int SDFileSystem::disk_read(char *buffer, int block_number) {
belloula	0:d07617f8ede9	227	// set read address for single block (CMD17)
belloula	0:d07617f8ede9	228	if(_cmd(17, block_number * 512) != 0) {
belloula	0:d07617f8ede9	229	return 1;
belloula	0:d07617f8ede9	230	}
belloula	0:d07617f8ede9	231
belloula	0:d07617f8ede9	232	// receive the data
belloula	0:d07617f8ede9	233	_read(buffer, 512);
belloula	0:d07617f8ede9	234	return 0;
belloula	0:d07617f8ede9	235	}
belloula	0:d07617f8ede9	236
belloula	0:d07617f8ede9	237	int SDFileSystem::disk_status() { return 0; }
belloula	0:d07617f8ede9	238	int SDFileSystem::disk_sync() { return 0; }
belloula	0:d07617f8ede9	239	int SDFileSystem::disk_sectors() { return _sectors; }
belloula	0:d07617f8ede9	240
belloula	0:d07617f8ede9	241	// PRIVATE FUNCTIONS
belloula	0:d07617f8ede9	242
belloula	0:d07617f8ede9	243	int SDFileSystem::_cmd(int cmd, int arg) {
belloula	0:d07617f8ede9	244	_cs = 0;
belloula	0:d07617f8ede9	245
belloula	0:d07617f8ede9	246	// send a command
belloula	0:d07617f8ede9	247	_spi.write(0x40 \| cmd);
belloula	0:d07617f8ede9	248	_spi.write(arg >> 24);
belloula	0:d07617f8ede9	249	_spi.write(arg >> 16);
belloula	0:d07617f8ede9	250	_spi.write(arg >> 8);
belloula	0:d07617f8ede9	251	_spi.write(arg >> 0);
belloula	0:d07617f8ede9	252	_spi.write(0x95);
belloula	0:d07617f8ede9	253
belloula	0:d07617f8ede9	254	// wait for the repsonse (response[7] == 0)
belloula	0:d07617f8ede9	255	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
belloula	0:d07617f8ede9	256	int response = _spi.write(0xFF);
belloula	0:d07617f8ede9	257	if(!(response & 0x80)) {
belloula	0:d07617f8ede9	258	_cs = 1;
belloula	0:d07617f8ede9	259	_spi.write(0xFF);
belloula	0:d07617f8ede9	260	return response;
belloula	0:d07617f8ede9	261	}
belloula	0:d07617f8ede9	262	}
belloula	0:d07617f8ede9	263	_cs = 1;
belloula	0:d07617f8ede9	264	_spi.write(0xFF);
belloula	0:d07617f8ede9	265	return -1; // timeout
belloula	0:d07617f8ede9	266	}
belloula	0:d07617f8ede9	267	int SDFileSystem::_cmdx(int cmd, int arg) {
belloula	0:d07617f8ede9	268	_cs = 0;
belloula	0:d07617f8ede9	269
belloula	0:d07617f8ede9	270	// send a command
belloula	0:d07617f8ede9	271	_spi.write(0x40 \| cmd);
belloula	0:d07617f8ede9	272	_spi.write(arg >> 24);
belloula	0:d07617f8ede9	273	_spi.write(arg >> 16);
belloula	0:d07617f8ede9	274	_spi.write(arg >> 8);
belloula	0:d07617f8ede9	275	_spi.write(arg >> 0);
belloula	0:d07617f8ede9	276	_spi.write(0x95);
belloula	0:d07617f8ede9	277
belloula	0:d07617f8ede9	278	// wait for the repsonse (response[7] == 0)
belloula	0:d07617f8ede9	279	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
belloula	0:d07617f8ede9	280	int response = _spi.write(0xFF);
belloula	0:d07617f8ede9	281	if(!(response & 0x80)) {
belloula	0:d07617f8ede9	282	return response;
belloula	0:d07617f8ede9	283	}
belloula	0:d07617f8ede9	284	}
belloula	0:d07617f8ede9	285	_cs = 1;
belloula	0:d07617f8ede9	286	_spi.write(0xFF);
belloula	0:d07617f8ede9	287	return -1; // timeout
belloula	0:d07617f8ede9	288	}
belloula	0:d07617f8ede9	289
belloula	0:d07617f8ede9	290
belloula	0:d07617f8ede9	291	int SDFileSystem::_cmd58() {
belloula	0:d07617f8ede9	292	_cs = 0;
belloula	0:d07617f8ede9	293	int arg = 0;
belloula	0:d07617f8ede9	294
belloula	0:d07617f8ede9	295	// send a command
belloula	0:d07617f8ede9	296	_spi.write(0x40 \| 58);
belloula	0:d07617f8ede9	297	_spi.write(arg >> 24);
belloula	0:d07617f8ede9	298	_spi.write(arg >> 16);
belloula	0:d07617f8ede9	299	_spi.write(arg >> 8);
belloula	0:d07617f8ede9	300	_spi.write(arg >> 0);
belloula	0:d07617f8ede9	301	_spi.write(0x95);
belloula	0:d07617f8ede9	302
belloula	0:d07617f8ede9	303	// wait for the repsonse (response[7] == 0)
belloula	0:d07617f8ede9	304	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
belloula	0:d07617f8ede9	305	int response = _spi.write(0xFF);
belloula	0:d07617f8ede9	306	if(!(response & 0x80)) {
belloula	0:d07617f8ede9	307	int ocr = _spi.write(0xFF) << 24;
belloula	0:d07617f8ede9	308	ocr \|= _spi.write(0xFF) << 16;
belloula	0:d07617f8ede9	309	ocr \|= _spi.write(0xFF) << 8;
belloula	0:d07617f8ede9	310	ocr \|= _spi.write(0xFF) << 0;
belloula	0:d07617f8ede9	311	// printf("OCR = 0x%08X\n", ocr);
belloula	0:d07617f8ede9	312	_cs = 1;
belloula	0:d07617f8ede9	313	_spi.write(0xFF);
belloula	0:d07617f8ede9	314	return response;
belloula	0:d07617f8ede9	315	}
belloula	0:d07617f8ede9	316	}
belloula	0:d07617f8ede9	317	_cs = 1;
belloula	0:d07617f8ede9	318	_spi.write(0xFF);
belloula	0:d07617f8ede9	319	return -1; // timeout
belloula	0:d07617f8ede9	320	}
belloula	0:d07617f8ede9	321
belloula	0:d07617f8ede9	322	int SDFileSystem::_cmd8() {
belloula	0:d07617f8ede9	323	_cs = 0;
belloula	0:d07617f8ede9	324
belloula	0:d07617f8ede9	325	// send a command
belloula	0:d07617f8ede9	326	_spi.write(0x40 \| 8); // CMD8
belloula	0:d07617f8ede9	327	_spi.write(0x00); // reserved
belloula	0:d07617f8ede9	328	_spi.write(0x00); // reserved
belloula	0:d07617f8ede9	329	_spi.write(0x01); // 3.3v
belloula	0:d07617f8ede9	330	_spi.write(0xAA); // check pattern
belloula	0:d07617f8ede9	331	_spi.write(0x87); // crc
belloula	0:d07617f8ede9	332
belloula	0:d07617f8ede9	333	// wait for the repsonse (response[7] == 0)
belloula	0:d07617f8ede9	334	for(int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) {
belloula	0:d07617f8ede9	335	char response[5];
belloula	0:d07617f8ede9	336	response[0] = _spi.write(0xFF);
belloula	0:d07617f8ede9	337	if(!(response[0] & 0x80)) {
belloula	0:d07617f8ede9	338	for(int j=1; j<5; j++) {
belloula	0:d07617f8ede9	339	response[i] = _spi.write(0xFF);
belloula	0:d07617f8ede9	340	}
belloula	0:d07617f8ede9	341	_cs = 1;
belloula	0:d07617f8ede9	342	_spi.write(0xFF);
belloula	0:d07617f8ede9	343	return response[0];
belloula	0:d07617f8ede9	344	}
belloula	0:d07617f8ede9	345	}
belloula	0:d07617f8ede9	346	_cs = 1;
belloula	0:d07617f8ede9	347	_spi.write(0xFF);
belloula	0:d07617f8ede9	348	return -1; // timeout
belloula	0:d07617f8ede9	349	}
belloula	0:d07617f8ede9	350
belloula	0:d07617f8ede9	351	int SDFileSystem::_read(char *buffer, int length) {
belloula	0:d07617f8ede9	352	_cs = 0;
belloula	0:d07617f8ede9	353
belloula	0:d07617f8ede9	354	// read until start byte (0xFF)
belloula	0:d07617f8ede9	355	while(_spi.write(0xFF) != 0xFE);
belloula	0:d07617f8ede9	356
belloula	0:d07617f8ede9	357	// read data
belloula	0:d07617f8ede9	358	for(int i=0; i<length; i++) {
belloula	0:d07617f8ede9	359	buffer[i] = _spi.write(0xFF);
belloula	0:d07617f8ede9	360	}
belloula	0:d07617f8ede9	361	_spi.write(0xFF); // checksum
belloula	0:d07617f8ede9	362	_spi.write(0xFF);
belloula	0:d07617f8ede9	363
belloula	0:d07617f8ede9	364	_cs = 1;
belloula	0:d07617f8ede9	365	_spi.write(0xFF);
belloula	0:d07617f8ede9	366	return 0;
belloula	0:d07617f8ede9	367	}
belloula	0:d07617f8ede9	368
belloula	0:d07617f8ede9	369	int SDFileSystem::_write(const char *buffer, int length) {
belloula	0:d07617f8ede9	370	_cs = 0;
belloula	0:d07617f8ede9	371
belloula	0:d07617f8ede9	372	// indicate start of block
belloula	0:d07617f8ede9	373	_spi.write(0xFE);
belloula	0:d07617f8ede9	374
belloula	0:d07617f8ede9	375	// write the data
belloula	0:d07617f8ede9	376	for(int i=0; i<length; i++) {
belloula	0:d07617f8ede9	377	_spi.write(buffer[i]);
belloula	0:d07617f8ede9	378	}
belloula	0:d07617f8ede9	379
belloula	0:d07617f8ede9	380	// write the checksum
belloula	0:d07617f8ede9	381	_spi.write(0xFF);
belloula	0:d07617f8ede9	382	_spi.write(0xFF);
belloula	0:d07617f8ede9	383
belloula	0:d07617f8ede9	384	// check the repsonse token
belloula	0:d07617f8ede9	385	if((_spi.write(0xFF) & 0x1F) != 0x05) {
belloula	0:d07617f8ede9	386	_cs = 1;
belloula	0:d07617f8ede9	387	_spi.write(0xFF);
belloula	0:d07617f8ede9	388	return 1;
belloula	0:d07617f8ede9	389	}
belloula	0:d07617f8ede9	390
belloula	0:d07617f8ede9	391	// wait for write to finish
belloula	0:d07617f8ede9	392	while(_spi.write(0xFF) == 0);
belloula	0:d07617f8ede9	393
belloula	0:d07617f8ede9	394	_cs = 1;
belloula	0:d07617f8ede9	395	_spi.write(0xFF);
belloula	0:d07617f8ede9	396	return 0;
belloula	0:d07617f8ede9	397	}
belloula	0:d07617f8ede9	398
belloula	0:d07617f8ede9	399	static int ext_bits(char *data, int msb, int lsb) {
belloula	0:d07617f8ede9	400	int bits = 0;
belloula	0:d07617f8ede9	401	int size = 1 + msb - lsb;
belloula	0:d07617f8ede9	402	for(int i=0; i<size; i++) {
belloula	0:d07617f8ede9	403	int position = lsb + i;
belloula	0:d07617f8ede9	404	int byte = 15 - (position >> 3);
belloula	0:d07617f8ede9	405	int bit = position & 0x7;
belloula	0:d07617f8ede9	406	int value = (data[byte] >> bit) & 1;
belloula	0:d07617f8ede9	407	bits \|= value << i;
belloula	0:d07617f8ede9	408	}
belloula	0:d07617f8ede9	409	return bits;
belloula	0:d07617f8ede9	410	}
belloula	0:d07617f8ede9	411
belloula	0:d07617f8ede9	412	int SDFileSystem::_sd_sectors() {
belloula	0:d07617f8ede9	413
belloula	0:d07617f8ede9	414	// CMD9, Response R2 (R1 byte + 16-byte block read)
belloula	0:d07617f8ede9	415	if(_cmdx(9, 0) != 0) {
belloula	0:d07617f8ede9	416	fprintf(stderr, "Didn't get a response from the disk\n");
belloula	0:d07617f8ede9	417	return 0;
belloula	0:d07617f8ede9	418	}
belloula	0:d07617f8ede9	419
belloula	0:d07617f8ede9	420	char csd[16];
belloula	0:d07617f8ede9	421	if(_read(csd, 16) != 0) {
belloula	0:d07617f8ede9	422	fprintf(stderr, "Couldn't read csd response from disk\n");
belloula	0:d07617f8ede9	423	return 0;
belloula	0:d07617f8ede9	424	}
belloula	0:d07617f8ede9	425
belloula	0:d07617f8ede9	426	// csd_structure : csd[127:126]
belloula	0:d07617f8ede9	427	// c_size : csd[73:62]
belloula	0:d07617f8ede9	428	// c_size_mult : csd[49:47]
belloula	0:d07617f8ede9	429	// read_bl_len : csd[83:80] - the maximum read block length
belloula	0:d07617f8ede9	430
belloula	0:d07617f8ede9	431	int csd_structure = ext_bits(csd, 127, 126);
belloula	0:d07617f8ede9	432	int c_size = ext_bits(csd, 73, 62);
belloula	0:d07617f8ede9	433	int c_size_mult = ext_bits(csd, 49, 47);
belloula	0:d07617f8ede9	434	int read_bl_len = ext_bits(csd, 83, 80);
belloula	0:d07617f8ede9	435
belloula	0:d07617f8ede9	436	// printf("CSD_STRUCT = %d\n", csd_structure);
belloula	0:d07617f8ede9	437
belloula	0:d07617f8ede9	438	if(csd_structure != 0) {
belloula	0:d07617f8ede9	439	fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures\n");
belloula	0:d07617f8ede9	440	return 0;
belloula	0:d07617f8ede9	441	}
belloula	0:d07617f8ede9	442
belloula	0:d07617f8ede9	443	// memory capacity = BLOCKNR * BLOCK_LEN
belloula	0:d07617f8ede9	444	// where
belloula	0:d07617f8ede9	445	// BLOCKNR = (C_SIZE+1) * MULT
belloula	0:d07617f8ede9	446	// MULT = 2^(C_SIZE_MULT+2) (C_SIZE_MULT < 8)
belloula	0:d07617f8ede9	447	// BLOCK_LEN = 2^READ_BL_LEN, (READ_BL_LEN < 12)
belloula	0:d07617f8ede9	448
belloula	0:d07617f8ede9	449	int block_len = 1 << read_bl_len;
belloula	0:d07617f8ede9	450	int mult = 1 << (c_size_mult + 2);
belloula	0:d07617f8ede9	451	int blocknr = (c_size + 1) * mult;
belloula	0:d07617f8ede9	452	int capacity = blocknr * block_len;
belloula	0:d07617f8ede9	453
belloula	0:d07617f8ede9	454	int blocks = capacity / 512;
belloula	0:d07617f8ede9	455
belloula	0:d07617f8ede9	456	return blocks;
belloula	0:d07617f8ede9	457	}

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	17 Oct 2011
Imports:	17
Forks:	0
Commits:	1
Dependents:	0
Dependencies:	1
Followers:	1

SDFileSystem.cpp@0:d07617f8ede9, 2011-10-17 (annotated)

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