Assignment_2_XG - Test session

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Xavier Gouesnard / Mbed 2 deprecated Assignment_2_XG

Test session

Dependencies: FatFileSystem MCP23017 WattBob_TextLCD mbed

Fork of Assignment_2_herpe by Xavier Herpe

SDFileSystem.cpp@0:aaddc17011a9, 2012-03-08 (annotated)

Committer:: xherpe
Date:: Thu Mar 08 16:32:35 2012 +0000
Revision:: 0:aaddc17011a9

Who changed what in which revision?

User	Revision	Line number	New contents of line
xherpe	0:aaddc17011a9	1	/* mbed SDFileSystem Library, for providing file access to SD cards
xherpe	0:aaddc17011a9	2	* Copyright (c) 2008-2010, sford
xherpe	0:aaddc17011a9	3	*
xherpe	0:aaddc17011a9	4	* Permission is hereby granted, free of charge, to any person obtaining a copy
xherpe	0:aaddc17011a9	5	* of this software and associated documentation files (the "Software"), to deal
xherpe	0:aaddc17011a9	6	* in the Software without restriction, including without limitation the rights
xherpe	0:aaddc17011a9	7	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
xherpe	0:aaddc17011a9	8	* copies of the Software, and to permit persons to whom the Software is
xherpe	0:aaddc17011a9	9	* furnished to do so, subject to the following conditions:
xherpe	0:aaddc17011a9	10	*
xherpe	0:aaddc17011a9	11	* The above copyright notice and this permission notice shall be included in
xherpe	0:aaddc17011a9	12	* all copies or substantial portions of the Software.
xherpe	0:aaddc17011a9	13	*
xherpe	0:aaddc17011a9	14	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
xherpe	0:aaddc17011a9	15	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
xherpe	0:aaddc17011a9	16	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
xherpe	0:aaddc17011a9	17	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
xherpe	0:aaddc17011a9	18	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
xherpe	0:aaddc17011a9	19	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
xherpe	0:aaddc17011a9	20	* THE SOFTWARE.
xherpe	0:aaddc17011a9	21	*/
xherpe	0:aaddc17011a9	22
xherpe	0:aaddc17011a9	23	/* Introduction
xherpe	0:aaddc17011a9	24	* ------------
xherpe	0:aaddc17011a9	25	* SD and MMC cards support a number of interfaces, but common to them all
xherpe	0:aaddc17011a9	26	* is one based on SPI. This is the one I'm implmenting because it means
xherpe	0:aaddc17011a9	27	* it is much more portable even though not so performant, and we already
xherpe	0:aaddc17011a9	28	* have the mbed SPI Interface!
xherpe	0:aaddc17011a9	29	*
xherpe	0:aaddc17011a9	30	* The main reference I'm using is Chapter 7, "SPI Mode" of:
xherpe	0:aaddc17011a9	31	* http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
xherpe	0:aaddc17011a9	32	*
xherpe	0:aaddc17011a9	33	* SPI Startup
xherpe	0:aaddc17011a9	34	* -----------
xherpe	0:aaddc17011a9	35	* The SD card powers up in SD mode. The SPI interface mode is selected by
xherpe	0:aaddc17011a9	36	* asserting CS low and sending the reset command (CMD0). The card will
xherpe	0:aaddc17011a9	37	* respond with a (R1) response.
xherpe	0:aaddc17011a9	38	*
xherpe	0:aaddc17011a9	39	* CMD8 is optionally sent to determine the voltage range supported, and
xherpe	0:aaddc17011a9	40	* indirectly determine whether it is a version 1.x SD/non-SD card or
xherpe	0:aaddc17011a9	41	* version 2.x. I'll just ignore this for now.
xherpe	0:aaddc17011a9	42	*
xherpe	0:aaddc17011a9	43	* ACMD41 is repeatedly issued to initialise the card, until "in idle"
xherpe	0:aaddc17011a9	44	* (bit 0) of the R1 response goes to '0', indicating it is initialised.
xherpe	0:aaddc17011a9	45	*
xherpe	0:aaddc17011a9	46	* You should also indicate whether the host supports High Capicity cards,
xherpe	0:aaddc17011a9	47	* and check whether the card is high capacity - i'll also ignore this
xherpe	0:aaddc17011a9	48	*
xherpe	0:aaddc17011a9	49	* SPI Protocol
xherpe	0:aaddc17011a9	50	* ------------
xherpe	0:aaddc17011a9	51	* The SD SPI protocol is based on transactions made up of 8-bit words, with
xherpe	0:aaddc17011a9	52	* the host starting every bus transaction by asserting the CS signal low. The
xherpe	0:aaddc17011a9	53	* card always responds to commands, data blocks and errors.
xherpe	0:aaddc17011a9	54	*
xherpe	0:aaddc17011a9	55	* The protocol supports a CRC, but by default it is off (except for the
xherpe	0:aaddc17011a9	56	* first reset CMD0, where the CRC can just be pre-calculated, and CMD8)
xherpe	0:aaddc17011a9	57	* I'll leave the CRC off I think!
xherpe	0:aaddc17011a9	58	*
xherpe	0:aaddc17011a9	59	* Standard capacity cards have variable data block sizes, whereas High
xherpe	0:aaddc17011a9	60	* Capacity cards fix the size of data block to 512 bytes. I'll therefore
xherpe	0:aaddc17011a9	61	* just always use the Standard Capacity cards with a block size of 512 bytes.
xherpe	0:aaddc17011a9	62	* This is set with CMD16.
xherpe	0:aaddc17011a9	63	*
xherpe	0:aaddc17011a9	64	* You can read and write single blocks (CMD17, CMD25) or multiple blocks
xherpe	0:aaddc17011a9	65	* (CMD18, CMD25). For simplicity, I'll just use single block accesses. When
xherpe	0:aaddc17011a9	66	* the card gets a read command, it responds with a response token, and then
xherpe	0:aaddc17011a9	67	* a data token or an error.
xherpe	0:aaddc17011a9	68	*
xherpe	0:aaddc17011a9	69	* SPI Command Format
xherpe	0:aaddc17011a9	70	* ------------------
xherpe	0:aaddc17011a9	71	* Commands are 6-bytes long, containing the command, 32-bit argument, and CRC.
xherpe	0:aaddc17011a9	72	*
xherpe	0:aaddc17011a9	73	* +---------------+------------+------------+-----------+----------+--------------+
xherpe	0:aaddc17011a9	74	* \| 01 \| cmd[5:0] \| arg[31:24] \| arg[23:16] \| arg[15:8] \| arg[7:0] \| crc[6:0] \| 1 \|
xherpe	0:aaddc17011a9	75	* +---------------+------------+------------+-----------+----------+--------------+
xherpe	0:aaddc17011a9	76	*
xherpe	0:aaddc17011a9	77	* As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95)
xherpe	0:aaddc17011a9	78	*
xherpe	0:aaddc17011a9	79	* All Application Specific commands shall be preceded with APP_CMD (CMD55).
xherpe	0:aaddc17011a9	80	*
xherpe	0:aaddc17011a9	81	* SPI Response Format
xherpe	0:aaddc17011a9	82	* -------------------
xherpe	0:aaddc17011a9	83	* The main response format (R1) is a status byte (normally zero). Key flags:
xherpe	0:aaddc17011a9	84	* idle - 1 if the card is in an idle state/initialising
xherpe	0:aaddc17011a9	85	* cmd - 1 if an illegal command code was detected
xherpe	0:aaddc17011a9	86	*
xherpe	0:aaddc17011a9	87	* +-------------------------------------------------+
xherpe	0:aaddc17011a9	88	* R1 \| 0 \| arg \| addr \| seq \| crc \| cmd \| erase \| idle \|
xherpe	0:aaddc17011a9	89	* +-------------------------------------------------+
xherpe	0:aaddc17011a9	90	*
xherpe	0:aaddc17011a9	91	* R1b is the same, except it is followed by a busy signal (zeros) until
xherpe	0:aaddc17011a9	92	* the first non-zero byte when it is ready again.
xherpe	0:aaddc17011a9	93	*
xherpe	0:aaddc17011a9	94	* Data Response Token
xherpe	0:aaddc17011a9	95	* -------------------
xherpe	0:aaddc17011a9	96	* Every data block written to the card is acknowledged by a byte
xherpe	0:aaddc17011a9	97	* response token
xherpe	0:aaddc17011a9	98	*
xherpe	0:aaddc17011a9	99	* +----------------------+
xherpe	0:aaddc17011a9	100	* \| xxx \| 0 \| status \| 1 \|
xherpe	0:aaddc17011a9	101	* +----------------------+
xherpe	0:aaddc17011a9	102	* 010 - OK!
xherpe	0:aaddc17011a9	103	* 101 - CRC Error
xherpe	0:aaddc17011a9	104	* 110 - Write Error
xherpe	0:aaddc17011a9	105	*
xherpe	0:aaddc17011a9	106	* Single Block Read and Write
xherpe	0:aaddc17011a9	107	* ---------------------------
xherpe	0:aaddc17011a9	108	*
xherpe	0:aaddc17011a9	109	* Block transfers have a byte header, followed by the data, followed
xherpe	0:aaddc17011a9	110	* by a 16-bit CRC. In our case, the data will always be 512 bytes.
xherpe	0:aaddc17011a9	111	*
xherpe	0:aaddc17011a9	112	* +------+---------+---------+- - - -+---------+-----------+----------+
xherpe	0:aaddc17011a9	113	* \| 0xFE \| data[0] \| data[1] \| \| data[n] \| crc[15:8] \| crc[7:0] \|
xherpe	0:aaddc17011a9	114	* +------+---------+---------+- - - -+---------+-----------+----------+
xherpe	0:aaddc17011a9	115	*/
xherpe	0:aaddc17011a9	116
xherpe	0:aaddc17011a9	117	#include "SDFileSystem.h"
xherpe	0:aaddc17011a9	118
xherpe	0:aaddc17011a9	119	#define SD_COMMAND_TIMEOUT 5000
xherpe	0:aaddc17011a9	120
xherpe	0:aaddc17011a9	121	SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) :
xherpe	0:aaddc17011a9	122	FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) {
xherpe	0:aaddc17011a9	123	_cs = 1;
xherpe	0:aaddc17011a9	124	}
xherpe	0:aaddc17011a9	125
xherpe	0:aaddc17011a9	126	#define R1_IDLE_STATE (1 << 0)
xherpe	0:aaddc17011a9	127	#define R1_ERASE_RESET (1 << 1)
xherpe	0:aaddc17011a9	128	#define R1_ILLEGAL_COMMAND (1 << 2)
xherpe	0:aaddc17011a9	129	#define R1_COM_CRC_ERROR (1 << 3)
xherpe	0:aaddc17011a9	130	#define R1_ERASE_SEQUENCE_ERROR (1 << 4)
xherpe	0:aaddc17011a9	131	#define R1_ADDRESS_ERROR (1 << 5)
xherpe	0:aaddc17011a9	132	#define R1_PARAMETER_ERROR (1 << 6)
xherpe	0:aaddc17011a9	133
xherpe	0:aaddc17011a9	134	// Types
xherpe	0:aaddc17011a9	135	// - v1.x Standard Capacity
xherpe	0:aaddc17011a9	136	// - v2.x Standard Capacity
xherpe	0:aaddc17011a9	137	// - v2.x High Capacity
xherpe	0:aaddc17011a9	138	// - Not recognised as an SD Card
xherpe	0:aaddc17011a9	139
xherpe	0:aaddc17011a9	140	#define SDCARD_FAIL 0
xherpe	0:aaddc17011a9	141	#define SDCARD_V1 1
xherpe	0:aaddc17011a9	142	#define SDCARD_V2 2
xherpe	0:aaddc17011a9	143	#define SDCARD_V2HC 3
xherpe	0:aaddc17011a9	144
xherpe	0:aaddc17011a9	145	int SDFileSystem::initialise_card() {
xherpe	0:aaddc17011a9	146	// Set to 100kHz for initialisation, and clock card with cs = 1
xherpe	0:aaddc17011a9	147	_spi.frequency(100000);
xherpe	0:aaddc17011a9	148	_cs = 1;
xherpe	0:aaddc17011a9	149	for(int i=0; i<16; i++) {
xherpe	0:aaddc17011a9	150	_spi.write(0xFF);
xherpe	0:aaddc17011a9	151	}
xherpe	0:aaddc17011a9	152
xherpe	0:aaddc17011a9	153	// send CMD0, should return with all zeros except IDLE STATE set (bit 0)
xherpe	0:aaddc17011a9	154	if(_cmd(0, 0) != R1_IDLE_STATE) {
xherpe	0:aaddc17011a9	155	fprintf(stderr, "No disk, or could not put SD card in to SPI idle state\n");
xherpe	0:aaddc17011a9	156	return SDCARD_FAIL;
xherpe	0:aaddc17011a9	157	}
xherpe	0:aaddc17011a9	158
xherpe	0:aaddc17011a9	159	// send CMD8 to determine whther it is ver 2.x
xherpe	0:aaddc17011a9	160	int r = _cmd8();
xherpe	0:aaddc17011a9	161	if(r == R1_IDLE_STATE) {
xherpe	0:aaddc17011a9	162	return initialise_card_v2();
xherpe	0:aaddc17011a9	163	} else if(r == (R1_IDLE_STATE \| R1_ILLEGAL_COMMAND)) {
xherpe	0:aaddc17011a9	164	return initialise_card_v1();
xherpe	0:aaddc17011a9	165	} else {
xherpe	0:aaddc17011a9	166	fprintf(stderr, "Not in idle state after sending CMD8 (not an SD card?)\n");
xherpe	0:aaddc17011a9	167	return SDCARD_FAIL;
xherpe	0:aaddc17011a9	168	}
xherpe	0:aaddc17011a9	169	}
xherpe	0:aaddc17011a9	170
xherpe	0:aaddc17011a9	171	int SDFileSystem::initialise_card_v1() {
xherpe	0:aaddc17011a9	172	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
xherpe	0:aaddc17011a9	173	_cmd(55, 0);
xherpe	0:aaddc17011a9	174	if(_cmd(41, 0) == 0) {
xherpe	0:aaddc17011a9	175	return SDCARD_V1;
xherpe	0:aaddc17011a9	176	}
xherpe	0:aaddc17011a9	177	}
xherpe	0:aaddc17011a9	178
xherpe	0:aaddc17011a9	179	fprintf(stderr, "Timeout waiting for v1.x card\n");
xherpe	0:aaddc17011a9	180	return SDCARD_FAIL;
xherpe	0:aaddc17011a9	181	}
xherpe	0:aaddc17011a9	182
xherpe	0:aaddc17011a9	183	int SDFileSystem::initialise_card_v2() {
xherpe	0:aaddc17011a9	184
xherpe	0:aaddc17011a9	185	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
xherpe	0:aaddc17011a9	186	_cmd(55, 0);
xherpe	0:aaddc17011a9	187	if(_cmd(41, 0) == 0) {
xherpe	0:aaddc17011a9	188	_cmd58();
xherpe	0:aaddc17011a9	189	return SDCARD_V2;
xherpe	0:aaddc17011a9	190	}
xherpe	0:aaddc17011a9	191	}
xherpe	0:aaddc17011a9	192
xherpe	0:aaddc17011a9	193	fprintf(stderr, "Timeout waiting for v2.x card\n");
xherpe	0:aaddc17011a9	194	return SDCARD_FAIL;
xherpe	0:aaddc17011a9	195	}
xherpe	0:aaddc17011a9	196
xherpe	0:aaddc17011a9	197	int SDFileSystem::disk_initialize() {
xherpe	0:aaddc17011a9	198
xherpe	0:aaddc17011a9	199	int i = initialise_card();
xherpe	0:aaddc17011a9	200	// printf("init card = %d\n", i);
xherpe	0:aaddc17011a9	201	// printf("OK\n");
xherpe	0:aaddc17011a9	202
xherpe	0:aaddc17011a9	203	_sectors = _sd_sectors();
xherpe	0:aaddc17011a9	204
xherpe	0:aaddc17011a9	205	// Set block length to 512 (CMD16)
xherpe	0:aaddc17011a9	206	if(_cmd(16, 512) != 0) {
xherpe	0:aaddc17011a9	207	fprintf(stderr, "Set 512-byte block timed out\n");
xherpe	0:aaddc17011a9	208	return 1;
xherpe	0:aaddc17011a9	209	}
xherpe	0:aaddc17011a9	210
xherpe	0:aaddc17011a9	211	_spi.frequency(1000000); // Set to 1MHz for data transfer
xherpe	0:aaddc17011a9	212	return 0;
xherpe	0:aaddc17011a9	213	}
xherpe	0:aaddc17011a9	214
xherpe	0:aaddc17011a9	215	int SDFileSystem::disk_write(const char *buffer, int block_number) {
xherpe	0:aaddc17011a9	216	// set write address for single block (CMD24)
xherpe	0:aaddc17011a9	217	if(_cmd(24, block_number * 512) != 0) {
xherpe	0:aaddc17011a9	218	return 1;
xherpe	0:aaddc17011a9	219	}
xherpe	0:aaddc17011a9	220
xherpe	0:aaddc17011a9	221	// send the data block
xherpe	0:aaddc17011a9	222	_write(buffer, 512);
xherpe	0:aaddc17011a9	223	return 0;
xherpe	0:aaddc17011a9	224	}
xherpe	0:aaddc17011a9	225
xherpe	0:aaddc17011a9	226	int SDFileSystem::disk_read(char *buffer, int block_number) {
xherpe	0:aaddc17011a9	227	// set read address for single block (CMD17)
xherpe	0:aaddc17011a9	228	if(_cmd(17, block_number * 512) != 0) {
xherpe	0:aaddc17011a9	229	return 1;
xherpe	0:aaddc17011a9	230	}
xherpe	0:aaddc17011a9	231
xherpe	0:aaddc17011a9	232	// receive the data
xherpe	0:aaddc17011a9	233	_read(buffer, 512);
xherpe	0:aaddc17011a9	234	return 0;
xherpe	0:aaddc17011a9	235	}
xherpe	0:aaddc17011a9	236
xherpe	0:aaddc17011a9	237	int SDFileSystem::disk_status() { return 0; }
xherpe	0:aaddc17011a9	238	int SDFileSystem::disk_sync() { return 0; }
xherpe	0:aaddc17011a9	239	int SDFileSystem::disk_sectors() { return _sectors; }
xherpe	0:aaddc17011a9	240
xherpe	0:aaddc17011a9	241	// PRIVATE FUNCTIONS
xherpe	0:aaddc17011a9	242
xherpe	0:aaddc17011a9	243	int SDFileSystem::_cmd(int cmd, int arg) {
xherpe	0:aaddc17011a9	244	_cs = 0;
xherpe	0:aaddc17011a9	245
xherpe	0:aaddc17011a9	246	// send a command
xherpe	0:aaddc17011a9	247	_spi.write(0x40 \| cmd);
xherpe	0:aaddc17011a9	248	_spi.write(arg >> 24);
xherpe	0:aaddc17011a9	249	_spi.write(arg >> 16);
xherpe	0:aaddc17011a9	250	_spi.write(arg >> 8);
xherpe	0:aaddc17011a9	251	_spi.write(arg >> 0);
xherpe	0:aaddc17011a9	252	_spi.write(0x95);
xherpe	0:aaddc17011a9	253
xherpe	0:aaddc17011a9	254	// wait for the repsonse (response[7] == 0)
xherpe	0:aaddc17011a9	255	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
xherpe	0:aaddc17011a9	256	int response = _spi.write(0xFF);
xherpe	0:aaddc17011a9	257	if(!(response & 0x80)) {
xherpe	0:aaddc17011a9	258	_cs = 1;
xherpe	0:aaddc17011a9	259	_spi.write(0xFF);
xherpe	0:aaddc17011a9	260	return response;
xherpe	0:aaddc17011a9	261	}
xherpe	0:aaddc17011a9	262	}
xherpe	0:aaddc17011a9	263	_cs = 1;
xherpe	0:aaddc17011a9	264	_spi.write(0xFF);
xherpe	0:aaddc17011a9	265	return -1; // timeout
xherpe	0:aaddc17011a9	266	}
xherpe	0:aaddc17011a9	267	int SDFileSystem::_cmdx(int cmd, int arg) {
xherpe	0:aaddc17011a9	268	_cs = 0;
xherpe	0:aaddc17011a9	269
xherpe	0:aaddc17011a9	270	// send a command
xherpe	0:aaddc17011a9	271	_spi.write(0x40 \| cmd);
xherpe	0:aaddc17011a9	272	_spi.write(arg >> 24);
xherpe	0:aaddc17011a9	273	_spi.write(arg >> 16);
xherpe	0:aaddc17011a9	274	_spi.write(arg >> 8);
xherpe	0:aaddc17011a9	275	_spi.write(arg >> 0);
xherpe	0:aaddc17011a9	276	_spi.write(0x95);
xherpe	0:aaddc17011a9	277
xherpe	0:aaddc17011a9	278	// wait for the repsonse (response[7] == 0)
xherpe	0:aaddc17011a9	279	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
xherpe	0:aaddc17011a9	280	int response = _spi.write(0xFF);
xherpe	0:aaddc17011a9	281	if(!(response & 0x80)) {
xherpe	0:aaddc17011a9	282	return response;
xherpe	0:aaddc17011a9	283	}
xherpe	0:aaddc17011a9	284	}
xherpe	0:aaddc17011a9	285	_cs = 1;
xherpe	0:aaddc17011a9	286	_spi.write(0xFF);
xherpe	0:aaddc17011a9	287	return -1; // timeout
xherpe	0:aaddc17011a9	288	}
xherpe	0:aaddc17011a9	289
xherpe	0:aaddc17011a9	290
xherpe	0:aaddc17011a9	291	int SDFileSystem::_cmd58() {
xherpe	0:aaddc17011a9	292	_cs = 0;
xherpe	0:aaddc17011a9	293	int arg = 0;
xherpe	0:aaddc17011a9	294
xherpe	0:aaddc17011a9	295	// send a command
xherpe	0:aaddc17011a9	296	_spi.write(0x40 \| 58);
xherpe	0:aaddc17011a9	297	_spi.write(arg >> 24);
xherpe	0:aaddc17011a9	298	_spi.write(arg >> 16);
xherpe	0:aaddc17011a9	299	_spi.write(arg >> 8);
xherpe	0:aaddc17011a9	300	_spi.write(arg >> 0);
xherpe	0:aaddc17011a9	301	_spi.write(0x95);
xherpe	0:aaddc17011a9	302
xherpe	0:aaddc17011a9	303	// wait for the repsonse (response[7] == 0)
xherpe	0:aaddc17011a9	304	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
xherpe	0:aaddc17011a9	305	int response = _spi.write(0xFF);
xherpe	0:aaddc17011a9	306	if(!(response & 0x80)) {
xherpe	0:aaddc17011a9	307	int ocr = _spi.write(0xFF) << 24;
xherpe	0:aaddc17011a9	308	ocr \|= _spi.write(0xFF) << 16;
xherpe	0:aaddc17011a9	309	ocr \|= _spi.write(0xFF) << 8;
xherpe	0:aaddc17011a9	310	ocr \|= _spi.write(0xFF) << 0;
xherpe	0:aaddc17011a9	311	// printf("OCR = 0x%08X\n", ocr);
xherpe	0:aaddc17011a9	312	_cs = 1;
xherpe	0:aaddc17011a9	313	_spi.write(0xFF);
xherpe	0:aaddc17011a9	314	return response;
xherpe	0:aaddc17011a9	315	}
xherpe	0:aaddc17011a9	316	}
xherpe	0:aaddc17011a9	317	_cs = 1;
xherpe	0:aaddc17011a9	318	_spi.write(0xFF);
xherpe	0:aaddc17011a9	319	return -1; // timeout
xherpe	0:aaddc17011a9	320	}
xherpe	0:aaddc17011a9	321
xherpe	0:aaddc17011a9	322	int SDFileSystem::_cmd8() {
xherpe	0:aaddc17011a9	323	_cs = 0;
xherpe	0:aaddc17011a9	324
xherpe	0:aaddc17011a9	325	// send a command
xherpe	0:aaddc17011a9	326	_spi.write(0x40 \| 8); // CMD8
xherpe	0:aaddc17011a9	327	_spi.write(0x00); // reserved
xherpe	0:aaddc17011a9	328	_spi.write(0x00); // reserved
xherpe	0:aaddc17011a9	329	_spi.write(0x01); // 3.3v
xherpe	0:aaddc17011a9	330	_spi.write(0xAA); // check pattern
xherpe	0:aaddc17011a9	331	_spi.write(0x87); // crc
xherpe	0:aaddc17011a9	332
xherpe	0:aaddc17011a9	333	// wait for the repsonse (response[7] == 0)
xherpe	0:aaddc17011a9	334	for(int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) {
xherpe	0:aaddc17011a9	335	char response[5];
xherpe	0:aaddc17011a9	336	response[0] = _spi.write(0xFF);
xherpe	0:aaddc17011a9	337	if(!(response[0] & 0x80)) {
xherpe	0:aaddc17011a9	338	for(int j=1; j<5; j++) {
xherpe	0:aaddc17011a9	339	response[i] = _spi.write(0xFF);
xherpe	0:aaddc17011a9	340	}
xherpe	0:aaddc17011a9	341	_cs = 1;
xherpe	0:aaddc17011a9	342	_spi.write(0xFF);
xherpe	0:aaddc17011a9	343	return response[0];
xherpe	0:aaddc17011a9	344	}
xherpe	0:aaddc17011a9	345	}
xherpe	0:aaddc17011a9	346	_cs = 1;
xherpe	0:aaddc17011a9	347	_spi.write(0xFF);
xherpe	0:aaddc17011a9	348	return -1; // timeout
xherpe	0:aaddc17011a9	349	}
xherpe	0:aaddc17011a9	350
xherpe	0:aaddc17011a9	351	int SDFileSystem::_read(char *buffer, int length) {
xherpe	0:aaddc17011a9	352	_cs = 0;
xherpe	0:aaddc17011a9	353
xherpe	0:aaddc17011a9	354	// read until start byte (0xFF)
xherpe	0:aaddc17011a9	355	while(_spi.write(0xFF) != 0xFE);
xherpe	0:aaddc17011a9	356
xherpe	0:aaddc17011a9	357	// read data
xherpe	0:aaddc17011a9	358	for(int i=0; i<length; i++) {
xherpe	0:aaddc17011a9	359	buffer[i] = _spi.write(0xFF);
xherpe	0:aaddc17011a9	360	}
xherpe	0:aaddc17011a9	361	_spi.write(0xFF); // checksum
xherpe	0:aaddc17011a9	362	_spi.write(0xFF);
xherpe	0:aaddc17011a9	363
xherpe	0:aaddc17011a9	364	_cs = 1;
xherpe	0:aaddc17011a9	365	_spi.write(0xFF);
xherpe	0:aaddc17011a9	366	return 0;
xherpe	0:aaddc17011a9	367	}
xherpe	0:aaddc17011a9	368
xherpe	0:aaddc17011a9	369	int SDFileSystem::_write(const char *buffer, int length) {
xherpe	0:aaddc17011a9	370	_cs = 0;
xherpe	0:aaddc17011a9	371
xherpe	0:aaddc17011a9	372	// indicate start of block
xherpe	0:aaddc17011a9	373	_spi.write(0xFE);
xherpe	0:aaddc17011a9	374
xherpe	0:aaddc17011a9	375	// write the data
xherpe	0:aaddc17011a9	376	for(int i=0; i<length; i++) {
xherpe	0:aaddc17011a9	377	_spi.write(buffer[i]);
xherpe	0:aaddc17011a9	378	}
xherpe	0:aaddc17011a9	379
xherpe	0:aaddc17011a9	380	// write the checksum
xherpe	0:aaddc17011a9	381	_spi.write(0xFF);
xherpe	0:aaddc17011a9	382	_spi.write(0xFF);
xherpe	0:aaddc17011a9	383
xherpe	0:aaddc17011a9	384	// check the repsonse token
xherpe	0:aaddc17011a9	385	if((_spi.write(0xFF) & 0x1F) != 0x05) {
xherpe	0:aaddc17011a9	386	_cs = 1;
xherpe	0:aaddc17011a9	387	_spi.write(0xFF);
xherpe	0:aaddc17011a9	388	return 1;
xherpe	0:aaddc17011a9	389	}
xherpe	0:aaddc17011a9	390
xherpe	0:aaddc17011a9	391	// wait for write to finish
xherpe	0:aaddc17011a9	392	while(_spi.write(0xFF) == 0);
xherpe	0:aaddc17011a9	393
xherpe	0:aaddc17011a9	394	_cs = 1;
xherpe	0:aaddc17011a9	395	_spi.write(0xFF);
xherpe	0:aaddc17011a9	396	return 0;
xherpe	0:aaddc17011a9	397	}
xherpe	0:aaddc17011a9	398
xherpe	0:aaddc17011a9	399	static int ext_bits(char *data, int msb, int lsb) {
xherpe	0:aaddc17011a9	400	int bits = 0;
xherpe	0:aaddc17011a9	401	int size = 1 + msb - lsb;
xherpe	0:aaddc17011a9	402	for(int i=0; i<size; i++) {
xherpe	0:aaddc17011a9	403	int position = lsb + i;
xherpe	0:aaddc17011a9	404	int byte = 15 - (position >> 3);
xherpe	0:aaddc17011a9	405	int bit = position & 0x7;
xherpe	0:aaddc17011a9	406	int value = (data[byte] >> bit) & 1;
xherpe	0:aaddc17011a9	407	bits \|= value << i;
xherpe	0:aaddc17011a9	408	}
xherpe	0:aaddc17011a9	409	return bits;
xherpe	0:aaddc17011a9	410	}
xherpe	0:aaddc17011a9	411
xherpe	0:aaddc17011a9	412	int SDFileSystem::_sd_sectors() {
xherpe	0:aaddc17011a9	413
xherpe	0:aaddc17011a9	414	// CMD9, Response R2 (R1 byte + 16-byte block read)
xherpe	0:aaddc17011a9	415	if(_cmdx(9, 0) != 0) {
xherpe	0:aaddc17011a9	416	fprintf(stderr, "Didn't get a response from the disk\n");
xherpe	0:aaddc17011a9	417	return 0;
xherpe	0:aaddc17011a9	418	}
xherpe	0:aaddc17011a9	419
xherpe	0:aaddc17011a9	420	char csd[16];
xherpe	0:aaddc17011a9	421	if(_read(csd, 16) != 0) {
xherpe	0:aaddc17011a9	422	fprintf(stderr, "Couldn't read csd response from disk\n");
xherpe	0:aaddc17011a9	423	return 0;
xherpe	0:aaddc17011a9	424	}
xherpe	0:aaddc17011a9	425
xherpe	0:aaddc17011a9	426	// csd_structure : csd[127:126]
xherpe	0:aaddc17011a9	427	// c_size : csd[73:62]
xherpe	0:aaddc17011a9	428	// c_size_mult : csd[49:47]
xherpe	0:aaddc17011a9	429	// read_bl_len : csd[83:80] - the maximum read block length
xherpe	0:aaddc17011a9	430
xherpe	0:aaddc17011a9	431	int csd_structure = ext_bits(csd, 127, 126);
xherpe	0:aaddc17011a9	432	int c_size = ext_bits(csd, 73, 62);
xherpe	0:aaddc17011a9	433	int c_size_mult = ext_bits(csd, 49, 47);
xherpe	0:aaddc17011a9	434	int read_bl_len = ext_bits(csd, 83, 80);
xherpe	0:aaddc17011a9	435
xherpe	0:aaddc17011a9	436	// printf("CSD_STRUCT = %d\n", csd_structure);
xherpe	0:aaddc17011a9	437
xherpe	0:aaddc17011a9	438	if(csd_structure != 0) {
xherpe	0:aaddc17011a9	439	fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures\n");
xherpe	0:aaddc17011a9	440	return 0;
xherpe	0:aaddc17011a9	441	}
xherpe	0:aaddc17011a9	442
xherpe	0:aaddc17011a9	443	// memory capacity = BLOCKNR * BLOCK_LEN
xherpe	0:aaddc17011a9	444	// where
xherpe	0:aaddc17011a9	445	// BLOCKNR = (C_SIZE+1) * MULT
xherpe	0:aaddc17011a9	446	// MULT = 2^(C_SIZE_MULT+2) (C_SIZE_MULT < 8)
xherpe	0:aaddc17011a9	447	// BLOCK_LEN = 2^READ_BL_LEN, (READ_BL_LEN < 12)
xherpe	0:aaddc17011a9	448
xherpe	0:aaddc17011a9	449	int block_len = 1 << read_bl_len;
xherpe	0:aaddc17011a9	450	int mult = 1 << (c_size_mult + 2);
xherpe	0:aaddc17011a9	451	int blocknr = (c_size + 1) * mult;
xherpe	0:aaddc17011a9	452	int capacity = blocknr * block_len;
xherpe	0:aaddc17011a9	453
xherpe	0:aaddc17011a9	454	int blocks = capacity / 512;
xherpe	0:aaddc17011a9	455
xherpe	0:aaddc17011a9	456	return blocks;
xherpe	0:aaddc17011a9	457	}

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	14 Mar 2017
Imports:	0
Forks:	0
Commits:	5
Dependents:	0
Dependencies:	4
Followers:	1

SDFileSystem.cpp@0:aaddc17011a9, 2012-03-08 (annotated)

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