SDFileSystem - nnnnn

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SDFileSystem.cpp@0:b1ddfc9a9b25, 2010-06-03 (annotated)

Committer:: simon
Date:: Thu Jun 03 16:32:50 2010 +0000
Revision:: 0:b1ddfc9a9b25
Child:: 3:a66a7f783ef0

Who changed what in which revision?

User	Revision	Line number	New contents of line
simon	0:b1ddfc9a9b25	1	/* mbed SDFileSystem Library, for providing file access to SD cards
simon	0:b1ddfc9a9b25	2	* Copyright (c) 2008-2010, sford
simon	0:b1ddfc9a9b25	3	*
simon	0:b1ddfc9a9b25	4	* Permission is hereby granted, free of charge, to any person obtaining a copy
simon	0:b1ddfc9a9b25	5	* of this software and associated documentation files (the "Software"), to deal
simon	0:b1ddfc9a9b25	6	* in the Software without restriction, including without limitation the rights
simon	0:b1ddfc9a9b25	7	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
simon	0:b1ddfc9a9b25	8	* copies of the Software, and to permit persons to whom the Software is
simon	0:b1ddfc9a9b25	9	* furnished to do so, subject to the following conditions:
simon	0:b1ddfc9a9b25	10	*
simon	0:b1ddfc9a9b25	11	* The above copyright notice and this permission notice shall be included in
simon	0:b1ddfc9a9b25	12	* all copies or substantial portions of the Software.
simon	0:b1ddfc9a9b25	13	*
simon	0:b1ddfc9a9b25	14	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
simon	0:b1ddfc9a9b25	15	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
simon	0:b1ddfc9a9b25	16	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
simon	0:b1ddfc9a9b25	17	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
simon	0:b1ddfc9a9b25	18	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
simon	0:b1ddfc9a9b25	19	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
simon	0:b1ddfc9a9b25	20	* THE SOFTWARE.
simon	0:b1ddfc9a9b25	21	*/
simon	0:b1ddfc9a9b25	22
simon	0:b1ddfc9a9b25	23	/* Introduction
simon	0:b1ddfc9a9b25	24	* ------------
simon	0:b1ddfc9a9b25	25	* SD and MMC cards support a number of interfaces, but common to them all
simon	0:b1ddfc9a9b25	26	* is one based on SPI. This is the one I'm implmenting because it means
simon	0:b1ddfc9a9b25	27	* it is much more portable even though not so performant, and we already
simon	0:b1ddfc9a9b25	28	* have the mbed SPI Interface!
simon	0:b1ddfc9a9b25	29	*
simon	0:b1ddfc9a9b25	30	* The main reference I'm using is Chapter 7, "SPI Mode" of:
simon	0:b1ddfc9a9b25	31	* http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
simon	0:b1ddfc9a9b25	32	*
simon	0:b1ddfc9a9b25	33	* SPI Startup
simon	0:b1ddfc9a9b25	34	* -----------
simon	0:b1ddfc9a9b25	35	* The SD card powers up in SD mode. The SPI interface mode is selected by
simon	0:b1ddfc9a9b25	36	* asserting CS low and sending the reset command (CMD0). The card will
simon	0:b1ddfc9a9b25	37	* respond with a (R1) response.
simon	0:b1ddfc9a9b25	38	*
simon	0:b1ddfc9a9b25	39	* CMD8 is optionally sent to determine the voltage range supported, and
simon	0:b1ddfc9a9b25	40	* indirectly determine whether it is a version 1.x SD/non-SD card or
simon	0:b1ddfc9a9b25	41	* version 2.x. I'll just ignore this for now.
simon	0:b1ddfc9a9b25	42	*
simon	0:b1ddfc9a9b25	43	* ACMD41 is repeatedly issued to initialise the card, until "in idle"
simon	0:b1ddfc9a9b25	44	* (bit 0) of the R1 response goes to '0', indicating it is initialised.
simon	0:b1ddfc9a9b25	45	*
simon	0:b1ddfc9a9b25	46	* You should also indicate whether the host supports High Capicity cards,
simon	0:b1ddfc9a9b25	47	* and check whether the card is high capacity - i'll also ignore this
simon	0:b1ddfc9a9b25	48	*
simon	0:b1ddfc9a9b25	49	* SPI Protocol
simon	0:b1ddfc9a9b25	50	* ------------
simon	0:b1ddfc9a9b25	51	* The SD SPI protocol is based on transactions made up of 8-bit words, with
simon	0:b1ddfc9a9b25	52	* the host starting every bus transaction by asserting the CS signal low. The
simon	0:b1ddfc9a9b25	53	* card always responds to commands, data blocks and errors.
simon	0:b1ddfc9a9b25	54	*
simon	0:b1ddfc9a9b25	55	* The protocol supports a CRC, but by default it is off (except for the
simon	0:b1ddfc9a9b25	56	* first reset CMD0, where the CRC can just be pre-calculated, and CMD8)
simon	0:b1ddfc9a9b25	57	* I'll leave the CRC off I think!
simon	0:b1ddfc9a9b25	58	*
simon	0:b1ddfc9a9b25	59	* Standard capacity cards have variable data block sizes, whereas High
simon	0:b1ddfc9a9b25	60	* Capacity cards fix the size of data block to 512 bytes. I'll therefore
simon	0:b1ddfc9a9b25	61	* just always use the Standard Capacity cards with a block size of 512 bytes.
simon	0:b1ddfc9a9b25	62	* This is set with CMD16.
simon	0:b1ddfc9a9b25	63	*
simon	0:b1ddfc9a9b25	64	* You can read and write single blocks (CMD17, CMD25) or multiple blocks
simon	0:b1ddfc9a9b25	65	* (CMD18, CMD25). For simplicity, I'll just use single block accesses. When
simon	0:b1ddfc9a9b25	66	* the card gets a read command, it responds with a response token, and then
simon	0:b1ddfc9a9b25	67	* a data token or an error.
simon	0:b1ddfc9a9b25	68	*
simon	0:b1ddfc9a9b25	69	* SPI Command Format
simon	0:b1ddfc9a9b25	70	* ------------------
simon	0:b1ddfc9a9b25	71	* Commands are 6-bytes long, containing the command, 32-bit argument, and CRC.
simon	0:b1ddfc9a9b25	72	*
simon	0:b1ddfc9a9b25	73	* +---------------+------------+------------+-----------+----------+--------------+
simon	0:b1ddfc9a9b25	74	* \| 01 \| cmd[5:0] \| arg[31:24] \| arg[23:16] \| arg[15:8] \| arg[7:0] \| crc[6:0] \| 1 \|
simon	0:b1ddfc9a9b25	75	* +---------------+------------+------------+-----------+----------+--------------+
simon	0:b1ddfc9a9b25	76	*
simon	0:b1ddfc9a9b25	77	* As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95)
simon	0:b1ddfc9a9b25	78	*
simon	0:b1ddfc9a9b25	79	* All Application Specific commands shall be preceded with APP_CMD (CMD55).
simon	0:b1ddfc9a9b25	80	*
simon	0:b1ddfc9a9b25	81	* SPI Response Format
simon	0:b1ddfc9a9b25	82	* -------------------
simon	0:b1ddfc9a9b25	83	* The main response format (R1) is a status byte (normally zero). Key flags:
simon	0:b1ddfc9a9b25	84	* idle - 1 if the card is in an idle state/initialising
simon	0:b1ddfc9a9b25	85	* cmd - 1 if an illegal command code was detected
simon	0:b1ddfc9a9b25	86	*
simon	0:b1ddfc9a9b25	87	* +-------------------------------------------------+
simon	0:b1ddfc9a9b25	88	* R1 \| 0 \| arg \| addr \| seq \| crc \| cmd \| erase \| idle \|
simon	0:b1ddfc9a9b25	89	* +-------------------------------------------------+
simon	0:b1ddfc9a9b25	90	*
simon	0:b1ddfc9a9b25	91	* R1b is the same, except it is followed by a busy signal (zeros) until
simon	0:b1ddfc9a9b25	92	* the first non-zero byte when it is ready again.
simon	0:b1ddfc9a9b25	93	*
simon	0:b1ddfc9a9b25	94	* Data Response Token
simon	0:b1ddfc9a9b25	95	* -------------------
simon	0:b1ddfc9a9b25	96	* Every data block written to the card is acknowledged by a byte
simon	0:b1ddfc9a9b25	97	* response token
simon	0:b1ddfc9a9b25	98	*
simon	0:b1ddfc9a9b25	99	* +----------------------+
simon	0:b1ddfc9a9b25	100	* \| xxx \| 0 \| status \| 1 \|
simon	0:b1ddfc9a9b25	101	* +----------------------+
simon	0:b1ddfc9a9b25	102	* 010 - OK!
simon	0:b1ddfc9a9b25	103	* 101 - CRC Error
simon	0:b1ddfc9a9b25	104	* 110 - Write Error
simon	0:b1ddfc9a9b25	105	*
simon	0:b1ddfc9a9b25	106	* Single Block Read and Write
simon	0:b1ddfc9a9b25	107	* ---------------------------
simon	0:b1ddfc9a9b25	108	*
simon	0:b1ddfc9a9b25	109	* Block transfers have a byte header, followed by the data, followed
simon	0:b1ddfc9a9b25	110	* by a 16-bit CRC. In our case, the data will always be 512 bytes.
simon	0:b1ddfc9a9b25	111	*
simon	0:b1ddfc9a9b25	112	* +------+---------+---------+- - - -+---------+-----------+----------+
simon	0:b1ddfc9a9b25	113	* \| 0xFE \| data[0] \| data[1] \| \| data[n] \| crc[15:8] \| crc[7:0] \|
simon	0:b1ddfc9a9b25	114	* +------+---------+---------+- - - -+---------+-----------+----------+
simon	0:b1ddfc9a9b25	115	*/
simon	0:b1ddfc9a9b25	116
simon	0:b1ddfc9a9b25	117	#include "SDFileSystem.h"
simon	0:b1ddfc9a9b25	118
simon	0:b1ddfc9a9b25	119	#define SD_COMMAND_TIMEOUT 5000
simon	0:b1ddfc9a9b25	120
simon	0:b1ddfc9a9b25	121	SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) :
simon	0:b1ddfc9a9b25	122	FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) {
simon	0:b1ddfc9a9b25	123	_cs = 1;
simon	0:b1ddfc9a9b25	124	}
simon	0:b1ddfc9a9b25	125
simon	0:b1ddfc9a9b25	126	#define R1_IDLE_STATE (1 << 0)
simon	0:b1ddfc9a9b25	127	#define R1_ERASE_RESET (1 << 1)
simon	0:b1ddfc9a9b25	128	#define R1_ILLEGAL_COMMAND (1 << 2)
simon	0:b1ddfc9a9b25	129	#define R1_COM_CRC_ERROR (1 << 3)
simon	0:b1ddfc9a9b25	130	#define R1_ERASE_SEQUENCE_ERROR (1 << 4)
simon	0:b1ddfc9a9b25	131	#define R1_ADDRESS_ERROR (1 << 5)
simon	0:b1ddfc9a9b25	132	#define R1_PARAMETER_ERROR (1 << 6)
simon	0:b1ddfc9a9b25	133
simon	0:b1ddfc9a9b25	134	// Types
simon	0:b1ddfc9a9b25	135	// - v1.x Standard Capacity
simon	0:b1ddfc9a9b25	136	// - v2.x Standard Capacity
simon	0:b1ddfc9a9b25	137	// - v2.x High Capacity
simon	0:b1ddfc9a9b25	138	// - Not recognised as an SD Card
simon	0:b1ddfc9a9b25	139
simon	0:b1ddfc9a9b25	140	#define SDCARD_FAIL 0
simon	0:b1ddfc9a9b25	141	#define SDCARD_V1 1
simon	0:b1ddfc9a9b25	142	#define SDCARD_V2 2
simon	0:b1ddfc9a9b25	143	#define SDCARD_V2HC 3
simon	0:b1ddfc9a9b25	144
simon	0:b1ddfc9a9b25	145	int SDFileSystem::initialise_card() {
simon	0:b1ddfc9a9b25	146	// Set to 100kHz for initialisation, and clock card with cs = 1
simon	0:b1ddfc9a9b25	147	_spi.frequency(100000);
simon	0:b1ddfc9a9b25	148	_cs = 1;
simon	0:b1ddfc9a9b25	149	for(int i=0; i<16; i++) {
simon	0:b1ddfc9a9b25	150	_spi.write(0xFF);
simon	0:b1ddfc9a9b25	151	}
simon	0:b1ddfc9a9b25	152
simon	0:b1ddfc9a9b25	153	// send CMD0, should return with all zeros except IDLE STATE set (bit 0)
simon	0:b1ddfc9a9b25	154	if(_cmd(0, 0) != R1_IDLE_STATE) {
simon	0:b1ddfc9a9b25	155	fprintf(stderr, "No disk, or could not put SD card in to SPI idle state\n");
simon	0:b1ddfc9a9b25	156	return SDCARD_FAIL;
simon	0:b1ddfc9a9b25	157	}
simon	0:b1ddfc9a9b25	158
simon	0:b1ddfc9a9b25	159	// send CMD8 to determine whther it is ver 2.x
simon	0:b1ddfc9a9b25	160	int r = _cmd8();
simon	0:b1ddfc9a9b25	161	if(r == R1_IDLE_STATE) {
simon	0:b1ddfc9a9b25	162	return initialise_card_v2();
simon	0:b1ddfc9a9b25	163	} else if(r == (R1_IDLE_STATE \| R1_ILLEGAL_COMMAND)) {
simon	0:b1ddfc9a9b25	164	return initialise_card_v1();
simon	0:b1ddfc9a9b25	165	} else {
simon	0:b1ddfc9a9b25	166	fprintf(stderr, "Not in idle state after sending CMD8 (not an SD card?)\n");
simon	0:b1ddfc9a9b25	167	return SDCARD_FAIL;
simon	0:b1ddfc9a9b25	168	}
simon	0:b1ddfc9a9b25	169	}
simon	0:b1ddfc9a9b25	170
simon	0:b1ddfc9a9b25	171	int SDFileSystem::initialise_card_v1() {
simon	0:b1ddfc9a9b25	172	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
simon	0:b1ddfc9a9b25	173	_cmd(55, 0);
simon	0:b1ddfc9a9b25	174	if(_cmd(41, 0) == 0) {
simon	0:b1ddfc9a9b25	175	return SDCARD_V1;
simon	0:b1ddfc9a9b25	176	}
simon	0:b1ddfc9a9b25	177	}
simon	0:b1ddfc9a9b25	178
simon	0:b1ddfc9a9b25	179	fprintf(stderr, "Timeout waiting for v1.x card\n");
simon	0:b1ddfc9a9b25	180	return SDCARD_FAIL;
simon	0:b1ddfc9a9b25	181	}
simon	0:b1ddfc9a9b25	182
simon	0:b1ddfc9a9b25	183	int SDFileSystem::initialise_card_v2() {
simon	0:b1ddfc9a9b25	184
simon	0:b1ddfc9a9b25	185	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
simon	0:b1ddfc9a9b25	186	_cmd(55, 0);
simon	0:b1ddfc9a9b25	187	if(_cmd(41, 0) == 0) {
simon	0:b1ddfc9a9b25	188	_cmd58();
simon	0:b1ddfc9a9b25	189	return SDCARD_V2;
simon	0:b1ddfc9a9b25	190	}
simon	0:b1ddfc9a9b25	191	}
simon	0:b1ddfc9a9b25	192
simon	0:b1ddfc9a9b25	193	fprintf(stderr, "Timeout waiting for v2.x card\n");
simon	0:b1ddfc9a9b25	194	return SDCARD_FAIL;
simon	0:b1ddfc9a9b25	195	}
simon	0:b1ddfc9a9b25	196
simon	0:b1ddfc9a9b25	197	int SDFileSystem::disk_initialize() {
simon	0:b1ddfc9a9b25	198
simon	0:b1ddfc9a9b25	199	int i = initialise_card();
simon	0:b1ddfc9a9b25	200	// printf("init card = %d\n", i);
simon	0:b1ddfc9a9b25	201	// printf("OK\n");
simon	0:b1ddfc9a9b25	202
simon	0:b1ddfc9a9b25	203	_sectors = _sd_sectors();
simon	0:b1ddfc9a9b25	204
simon	0:b1ddfc9a9b25	205	// Set block length to 512 (CMD16)
simon	0:b1ddfc9a9b25	206	if(_cmd(16, 512) != 0) {
simon	0:b1ddfc9a9b25	207	fprintf(stderr, "Set 512-byte block timed out\n");
simon	0:b1ddfc9a9b25	208	return 1;
simon	0:b1ddfc9a9b25	209	}
simon	0:b1ddfc9a9b25	210
simon	0:b1ddfc9a9b25	211	_spi.frequency(1000000); // Set to 1MHz for data transfer
simon	0:b1ddfc9a9b25	212	return 0;
simon	0:b1ddfc9a9b25	213	}
simon	0:b1ddfc9a9b25	214
simon	0:b1ddfc9a9b25	215	int SDFileSystem::disk_write(const char *buffer, int block_number) {
simon	0:b1ddfc9a9b25	216	// set write address for single block (CMD24)
simon	0:b1ddfc9a9b25	217	if(_cmd(24, block_number * 512) != 0) {
simon	0:b1ddfc9a9b25	218	return 1;
simon	0:b1ddfc9a9b25	219	}
simon	0:b1ddfc9a9b25	220
simon	0:b1ddfc9a9b25	221	// send the data block
simon	0:b1ddfc9a9b25	222	_write(buffer, 512);
simon	0:b1ddfc9a9b25	223	return 0;
simon	0:b1ddfc9a9b25	224	}
simon	0:b1ddfc9a9b25	225
simon	0:b1ddfc9a9b25	226	int SDFileSystem::disk_read(char *buffer, int block_number) {
simon	0:b1ddfc9a9b25	227	// set read address for single block (CMD17)
simon	0:b1ddfc9a9b25	228	if(_cmd(17, block_number * 512) != 0) {
simon	0:b1ddfc9a9b25	229	return 1;
simon	0:b1ddfc9a9b25	230	}
simon	0:b1ddfc9a9b25	231
simon	0:b1ddfc9a9b25	232	// receive the data
simon	0:b1ddfc9a9b25	233	_read(buffer, 512);
simon	0:b1ddfc9a9b25	234	return 0;
simon	0:b1ddfc9a9b25	235	}
simon	0:b1ddfc9a9b25	236
simon	0:b1ddfc9a9b25	237	int SDFileSystem::disk_status() { return 0; }
simon	0:b1ddfc9a9b25	238	int SDFileSystem::disk_sync() { return 0; }
simon	0:b1ddfc9a9b25	239	int SDFileSystem::disk_sectors() { return _sectors; }
simon	0:b1ddfc9a9b25	240
simon	0:b1ddfc9a9b25	241	// PRIVATE FUNCTIONS
simon	0:b1ddfc9a9b25	242
simon	0:b1ddfc9a9b25	243	int SDFileSystem::_cmd(int cmd, int arg) {
simon	0:b1ddfc9a9b25	244	_cs = 0;
simon	0:b1ddfc9a9b25	245
simon	0:b1ddfc9a9b25	246	// send a command
simon	0:b1ddfc9a9b25	247	_spi.write(0x40 \| cmd);
simon	0:b1ddfc9a9b25	248	_spi.write(arg >> 24);
simon	0:b1ddfc9a9b25	249	_spi.write(arg >> 16);
simon	0:b1ddfc9a9b25	250	_spi.write(arg >> 8);
simon	0:b1ddfc9a9b25	251	_spi.write(arg >> 0);
simon	0:b1ddfc9a9b25	252	_spi.write(0x95);
simon	0:b1ddfc9a9b25	253
simon	0:b1ddfc9a9b25	254	// wait for the repsonse (response[7] == 0)
simon	0:b1ddfc9a9b25	255	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
simon	0:b1ddfc9a9b25	256	int response = _spi.write(0xFF);
simon	0:b1ddfc9a9b25	257	if(!(response & 0x80)) {
simon	0:b1ddfc9a9b25	258	_cs = 1;
simon	0:b1ddfc9a9b25	259	_spi.write(0xFF);
simon	0:b1ddfc9a9b25	260	return response;
simon	0:b1ddfc9a9b25	261	}
simon	0:b1ddfc9a9b25	262	}
simon	0:b1ddfc9a9b25	263	_cs = 1;
simon	0:b1ddfc9a9b25	264	_spi.write(0xFF);
simon	0:b1ddfc9a9b25	265	return -1; // timeout
simon	0:b1ddfc9a9b25	266	}
simon	0:b1ddfc9a9b25	267	int SDFileSystem::_cmdx(int cmd, int arg) {
simon	0:b1ddfc9a9b25	268	_cs = 0;
simon	0:b1ddfc9a9b25	269
simon	0:b1ddfc9a9b25	270	// send a command
simon	0:b1ddfc9a9b25	271	_spi.write(0x40 \| cmd);
simon	0:b1ddfc9a9b25	272	_spi.write(arg >> 24);
simon	0:b1ddfc9a9b25	273	_spi.write(arg >> 16);
simon	0:b1ddfc9a9b25	274	_spi.write(arg >> 8);
simon	0:b1ddfc9a9b25	275	_spi.write(arg >> 0);
simon	0:b1ddfc9a9b25	276	_spi.write(0x95);
simon	0:b1ddfc9a9b25	277
simon	0:b1ddfc9a9b25	278	// wait for the repsonse (response[7] == 0)
simon	0:b1ddfc9a9b25	279	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
simon	0:b1ddfc9a9b25	280	int response = _spi.write(0xFF);
simon	0:b1ddfc9a9b25	281	if(!(response & 0x80)) {
simon	0:b1ddfc9a9b25	282	return response;
simon	0:b1ddfc9a9b25	283	}
simon	0:b1ddfc9a9b25	284	}
simon	0:b1ddfc9a9b25	285	_cs = 1;
simon	0:b1ddfc9a9b25	286	_spi.write(0xFF);
simon	0:b1ddfc9a9b25	287	return -1; // timeout
simon	0:b1ddfc9a9b25	288	}
simon	0:b1ddfc9a9b25	289
simon	0:b1ddfc9a9b25	290
simon	0:b1ddfc9a9b25	291	int SDFileSystem::_cmd58() {
simon	0:b1ddfc9a9b25	292	_cs = 0;
simon	0:b1ddfc9a9b25	293	int arg = 0;
simon	0:b1ddfc9a9b25	294
simon	0:b1ddfc9a9b25	295	// send a command
simon	0:b1ddfc9a9b25	296	_spi.write(0x40 \| 58);
simon	0:b1ddfc9a9b25	297	_spi.write(arg >> 24);
simon	0:b1ddfc9a9b25	298	_spi.write(arg >> 16);
simon	0:b1ddfc9a9b25	299	_spi.write(arg >> 8);
simon	0:b1ddfc9a9b25	300	_spi.write(arg >> 0);
simon	0:b1ddfc9a9b25	301	_spi.write(0x95);
simon	0:b1ddfc9a9b25	302
simon	0:b1ddfc9a9b25	303	// wait for the repsonse (response[7] == 0)
simon	0:b1ddfc9a9b25	304	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
simon	0:b1ddfc9a9b25	305	int response = _spi.write(0xFF);
simon	0:b1ddfc9a9b25	306	if(!(response & 0x80)) {
simon	0:b1ddfc9a9b25	307	int ocr = _spi.write(0xFF) << 24;
simon	0:b1ddfc9a9b25	308	ocr \|= _spi.write(0xFF) << 16;
simon	0:b1ddfc9a9b25	309	ocr \|= _spi.write(0xFF) << 8;
simon	0:b1ddfc9a9b25	310	ocr \|= _spi.write(0xFF) << 0;
simon	0:b1ddfc9a9b25	311	// printf("OCR = 0x%08X\n", ocr);
simon	0:b1ddfc9a9b25	312	_cs = 1;
simon	0:b1ddfc9a9b25	313	_spi.write(0xFF);
simon	0:b1ddfc9a9b25	314	return response;
simon	0:b1ddfc9a9b25	315	}
simon	0:b1ddfc9a9b25	316	}
simon	0:b1ddfc9a9b25	317	_cs = 1;
simon	0:b1ddfc9a9b25	318	_spi.write(0xFF);
simon	0:b1ddfc9a9b25	319	return -1; // timeout
simon	0:b1ddfc9a9b25	320	}
simon	0:b1ddfc9a9b25	321
simon	0:b1ddfc9a9b25	322	int SDFileSystem::_cmd8() {
simon	0:b1ddfc9a9b25	323	_cs = 0;
simon	0:b1ddfc9a9b25	324
simon	0:b1ddfc9a9b25	325	// send a command
simon	0:b1ddfc9a9b25	326	_spi.write(0x40 \| 8); // CMD8
simon	0:b1ddfc9a9b25	327	_spi.write(0x00); // reserved
simon	0:b1ddfc9a9b25	328	_spi.write(0x00); // reserved
simon	0:b1ddfc9a9b25	329	_spi.write(0x01); // 3.3v
simon	0:b1ddfc9a9b25	330	_spi.write(0xAA); // check pattern
simon	0:b1ddfc9a9b25	331	_spi.write(0x87); // crc
simon	0:b1ddfc9a9b25	332
simon	0:b1ddfc9a9b25	333	// wait for the repsonse (response[7] == 0)
simon	0:b1ddfc9a9b25	334	for(int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) {
simon	0:b1ddfc9a9b25	335	char response[5];
simon	0:b1ddfc9a9b25	336	response[0] = _spi.write(0xFF);
simon	0:b1ddfc9a9b25	337	if(!(response[0] & 0x80)) {
simon	0:b1ddfc9a9b25	338	for(int j=1; j<5; j++) {
simon	0:b1ddfc9a9b25	339	response[i] = _spi.write(0xFF);
simon	0:b1ddfc9a9b25	340	}
simon	0:b1ddfc9a9b25	341	_cs = 1;
simon	0:b1ddfc9a9b25	342	_spi.write(0xFF);
simon	0:b1ddfc9a9b25	343	return response[0];
simon	0:b1ddfc9a9b25	344	}
simon	0:b1ddfc9a9b25	345	}
simon	0:b1ddfc9a9b25	346	_cs = 1;
simon	0:b1ddfc9a9b25	347	_spi.write(0xFF);
simon	0:b1ddfc9a9b25	348	return -1; // timeout
simon	0:b1ddfc9a9b25	349	}
simon	0:b1ddfc9a9b25	350
simon	0:b1ddfc9a9b25	351	int SDFileSystem::_read(char *buffer, int length) {
simon	0:b1ddfc9a9b25	352	_cs = 0;
simon	0:b1ddfc9a9b25	353
simon	0:b1ddfc9a9b25	354	// read until start byte (0xFF)
simon	0:b1ddfc9a9b25	355	while(_spi.write(0xFF) != 0xFE);
simon	0:b1ddfc9a9b25	356
simon	0:b1ddfc9a9b25	357	// read data
simon	0:b1ddfc9a9b25	358	for(int i=0; i<length; i++) {
simon	0:b1ddfc9a9b25	359	buffer[i] = _spi.write(0xFF);
simon	0:b1ddfc9a9b25	360	}
simon	0:b1ddfc9a9b25	361	_spi.write(0xFF); // checksum
simon	0:b1ddfc9a9b25	362	_spi.write(0xFF);
simon	0:b1ddfc9a9b25	363
simon	0:b1ddfc9a9b25	364	_cs = 1;
simon	0:b1ddfc9a9b25	365	_spi.write(0xFF);
simon	0:b1ddfc9a9b25	366	return 0;
simon	0:b1ddfc9a9b25	367	}
simon	0:b1ddfc9a9b25	368
simon	0:b1ddfc9a9b25	369	int SDFileSystem::_write(const char *buffer, int length) {
simon	0:b1ddfc9a9b25	370	_cs = 0;
simon	0:b1ddfc9a9b25	371
simon	0:b1ddfc9a9b25	372	// indicate start of block
simon	0:b1ddfc9a9b25	373	_spi.write(0xFE);
simon	0:b1ddfc9a9b25	374
simon	0:b1ddfc9a9b25	375	// write the data
simon	0:b1ddfc9a9b25	376	for(int i=0; i<length; i++) {
simon	0:b1ddfc9a9b25	377	_spi.write(buffer[i]);
simon	0:b1ddfc9a9b25	378	}
simon	0:b1ddfc9a9b25	379
simon	0:b1ddfc9a9b25	380	// write the checksum
simon	0:b1ddfc9a9b25	381	_spi.write(0xFF);
simon	0:b1ddfc9a9b25	382	_spi.write(0xFF);
simon	0:b1ddfc9a9b25	383
simon	0:b1ddfc9a9b25	384	// check the repsonse token
simon	0:b1ddfc9a9b25	385	if((_spi.write(0xFF) & 0x1F) != 0x05) {
simon	0:b1ddfc9a9b25	386	_cs = 1;
simon	0:b1ddfc9a9b25	387	_spi.write(0xFF);
simon	0:b1ddfc9a9b25	388	return 1;
simon	0:b1ddfc9a9b25	389	}
simon	0:b1ddfc9a9b25	390
simon	0:b1ddfc9a9b25	391	// wait for write to finish
simon	0:b1ddfc9a9b25	392	while(_spi.write(0xFF) == 0);
simon	0:b1ddfc9a9b25	393
simon	0:b1ddfc9a9b25	394	_cs = 1;
simon	0:b1ddfc9a9b25	395	_spi.write(0xFF);
simon	0:b1ddfc9a9b25	396	return 0;
simon	0:b1ddfc9a9b25	397	}
simon	0:b1ddfc9a9b25	398
simon	0:b1ddfc9a9b25	399	static int ext_bits(char *data, int msb, int lsb) {
simon	0:b1ddfc9a9b25	400	int bits = 0;
simon	0:b1ddfc9a9b25	401	int size = 1 + msb - lsb;
simon	0:b1ddfc9a9b25	402	for(int i=0; i<size; i++) {
simon	0:b1ddfc9a9b25	403	int position = lsb + i;
simon	0:b1ddfc9a9b25	404	int byte = 15 - (position >> 3);
simon	0:b1ddfc9a9b25	405	int bit = position & 0x7;
simon	0:b1ddfc9a9b25	406	int value = (data[byte] >> bit) & 1;
simon	0:b1ddfc9a9b25	407	bits \|= value << i;
simon	0:b1ddfc9a9b25	408	}
simon	0:b1ddfc9a9b25	409	return bits;
simon	0:b1ddfc9a9b25	410	}
simon	0:b1ddfc9a9b25	411
simon	0:b1ddfc9a9b25	412	int SDFileSystem::_sd_sectors() {
simon	0:b1ddfc9a9b25	413
simon	0:b1ddfc9a9b25	414	// CMD9, Response R2 (R1 byte + 16-byte block read)
simon	0:b1ddfc9a9b25	415	if(_cmdx(9, 0) != 0) {
simon	0:b1ddfc9a9b25	416	fprintf(stderr, "Didn't get a response from the disk\n");
simon	0:b1ddfc9a9b25	417	return 0;
simon	0:b1ddfc9a9b25	418	}
simon	0:b1ddfc9a9b25	419
simon	0:b1ddfc9a9b25	420	char csd[16];
simon	0:b1ddfc9a9b25	421	if(_read(csd, 16) != 0) {
simon	0:b1ddfc9a9b25	422	fprintf(stderr, "Couldn't read csd response from disk\n");
simon	0:b1ddfc9a9b25	423	return 0;
simon	0:b1ddfc9a9b25	424	}
simon	0:b1ddfc9a9b25	425
simon	0:b1ddfc9a9b25	426	// csd_structure : csd[127:126]
simon	0:b1ddfc9a9b25	427	// c_size : csd[73:62]
simon	0:b1ddfc9a9b25	428	// c_size_mult : csd[49:47]
simon	0:b1ddfc9a9b25	429	// read_bl_len : csd[83:80] - the maximum read block length
simon	0:b1ddfc9a9b25	430
simon	0:b1ddfc9a9b25	431	int csd_structure = ext_bits(csd, 127, 126);
simon	0:b1ddfc9a9b25	432	int c_size = ext_bits(csd, 73, 62);
simon	0:b1ddfc9a9b25	433	int c_size_mult = ext_bits(csd, 49, 47);
simon	0:b1ddfc9a9b25	434	int read_bl_len = ext_bits(csd, 83, 80);
simon	0:b1ddfc9a9b25	435
simon	0:b1ddfc9a9b25	436	// printf("CSD_STRUCT = %d\n", csd_structure);
simon	0:b1ddfc9a9b25	437
simon	0:b1ddfc9a9b25	438	if(csd_structure != 0) {
simon	0:b1ddfc9a9b25	439	fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures\n");
simon	0:b1ddfc9a9b25	440	return 0;
simon	0:b1ddfc9a9b25	441	}
simon	0:b1ddfc9a9b25	442
simon	0:b1ddfc9a9b25	443	// memory capacity = BLOCKNR * BLOCK_LEN
simon	0:b1ddfc9a9b25	444	// where
simon	0:b1ddfc9a9b25	445	// BLOCKNR = (C_SIZE+1) * MULT
simon	0:b1ddfc9a9b25	446	// MULT = 2^(C_SIZE_MULT+2) (C_SIZE_MULT < 8)
simon	0:b1ddfc9a9b25	447	// BLOCK_LEN = 2^READ_BL_LEN, (READ_BL_LEN < 12)
simon	0:b1ddfc9a9b25	448
simon	0:b1ddfc9a9b25	449	int block_len = 1 << read_bl_len;
simon	0:b1ddfc9a9b25	450	int mult = 1 << (c_size_mult + 2);
simon	0:b1ddfc9a9b25	451	int blocknr = (c_size + 1) * mult;
simon	0:b1ddfc9a9b25	452	int capacity = blocknr * block_len;
simon	0:b1ddfc9a9b25	453
simon	0:b1ddfc9a9b25	454	int blocks = capacity / 512;
simon	0:b1ddfc9a9b25	455
simon	0:b1ddfc9a9b25	456	return blocks;
simon	0:b1ddfc9a9b25	457	}

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Type:	Library
Created:	18 Aug 2015
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SDFileSystem.cpp@0:b1ddfc9a9b25, 2010-06-03 (annotated)

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