MI0283QT_tst - MI0283QT Library Program demostration

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clemente di caprio / Mbed 2 deprecated MI0283QT_tst

MI0283QT Library Program demostration

SDFileSystem.cpp@0:4c87cf4af8b5, 2012-05-26 (annotated)

Committer:: clemente
Date:: Sat May 26 21:03:21 2012 +0000
Revision:: 0:4c87cf4af8b5

Who changed what in which revision?

User	Revision	Line number	New contents of line
clemente	0:4c87cf4af8b5	1	/* mbed SDFileSystem Library, for providing file access to SD cards
clemente	0:4c87cf4af8b5	2	* Copyright (c) 2008-2010, sford
clemente	0:4c87cf4af8b5	3	*
clemente	0:4c87cf4af8b5	4	* Permission is hereby granted, free of charge, to any person obtaining a copy
clemente	0:4c87cf4af8b5	5	* of this software and associated documentation files (the "Software"), to deal
clemente	0:4c87cf4af8b5	6	* in the Software without restriction, including without limitation the rights
clemente	0:4c87cf4af8b5	7	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
clemente	0:4c87cf4af8b5	8	* copies of the Software, and to permit persons to whom the Software is
clemente	0:4c87cf4af8b5	9	* furnished to do so, subject to the following conditions:
clemente	0:4c87cf4af8b5	10	*
clemente	0:4c87cf4af8b5	11	* The above copyright notice and this permission notice shall be included in
clemente	0:4c87cf4af8b5	12	* all copies or substantial portions of the Software.
clemente	0:4c87cf4af8b5	13	*
clemente	0:4c87cf4af8b5	14	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
clemente	0:4c87cf4af8b5	15	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
clemente	0:4c87cf4af8b5	16	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
clemente	0:4c87cf4af8b5	17	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
clemente	0:4c87cf4af8b5	18	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
clemente	0:4c87cf4af8b5	19	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
clemente	0:4c87cf4af8b5	20	* THE SOFTWARE.
clemente	0:4c87cf4af8b5	21	*/
clemente	0:4c87cf4af8b5	22
clemente	0:4c87cf4af8b5	23	/* Introduction
clemente	0:4c87cf4af8b5	24	* ------------
clemente	0:4c87cf4af8b5	25	* SD and MMC cards support a number of interfaces, but common to them all
clemente	0:4c87cf4af8b5	26	* is one based on SPI. This is the one I'm implmenting because it means
clemente	0:4c87cf4af8b5	27	* it is much more portable even though not so performant, and we already
clemente	0:4c87cf4af8b5	28	* have the mbed SPI Interface!
clemente	0:4c87cf4af8b5	29	*
clemente	0:4c87cf4af8b5	30	* The main reference I'm using is Chapter 7, "SPI Mode" of:
clemente	0:4c87cf4af8b5	31	* http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
clemente	0:4c87cf4af8b5	32	*
clemente	0:4c87cf4af8b5	33	* SPI Startup
clemente	0:4c87cf4af8b5	34	* -----------
clemente	0:4c87cf4af8b5	35	* The SD card powers up in SD mode. The SPI interface mode is selected by
clemente	0:4c87cf4af8b5	36	* asserting CS low and sending the reset command (CMD0). The card will
clemente	0:4c87cf4af8b5	37	* respond with a (R1) response.
clemente	0:4c87cf4af8b5	38	*
clemente	0:4c87cf4af8b5	39	* CMD8 is optionally sent to determine the voltage range supported, and
clemente	0:4c87cf4af8b5	40	* indirectly determine whether it is a version 1.x SD/non-SD card or
clemente	0:4c87cf4af8b5	41	* version 2.x. I'll just ignore this for now.
clemente	0:4c87cf4af8b5	42	*
clemente	0:4c87cf4af8b5	43	* ACMD41 is repeatedly issued to initialise the card, until "in idle"
clemente	0:4c87cf4af8b5	44	* (bit 0) of the R1 response goes to '0', indicating it is initialised.
clemente	0:4c87cf4af8b5	45	*
clemente	0:4c87cf4af8b5	46	* You should also indicate whether the host supports High Capicity cards,
clemente	0:4c87cf4af8b5	47	* and check whether the card is high capacity - i'll also ignore this
clemente	0:4c87cf4af8b5	48	*
clemente	0:4c87cf4af8b5	49	* SPI Protocol
clemente	0:4c87cf4af8b5	50	* ------------
clemente	0:4c87cf4af8b5	51	* The SD SPI protocol is based on transactions made up of 8-bit words, with
clemente	0:4c87cf4af8b5	52	* the host starting every bus transaction by asserting the CS signal low. The
clemente	0:4c87cf4af8b5	53	* card always responds to commands, data blocks and errors.
clemente	0:4c87cf4af8b5	54	*
clemente	0:4c87cf4af8b5	55	* The protocol supports a CRC, but by default it is off (except for the
clemente	0:4c87cf4af8b5	56	* first reset CMD0, where the CRC can just be pre-calculated, and CMD8)
clemente	0:4c87cf4af8b5	57	* I'll leave the CRC off I think!
clemente	0:4c87cf4af8b5	58	*
clemente	0:4c87cf4af8b5	59	* Standard capacity cards have variable data block sizes, whereas High
clemente	0:4c87cf4af8b5	60	* Capacity cards fix the size of data block to 512 bytes. I'll therefore
clemente	0:4c87cf4af8b5	61	* just always use the Standard Capacity cards with a block size of 512 bytes.
clemente	0:4c87cf4af8b5	62	* This is set with CMD16.
clemente	0:4c87cf4af8b5	63	*
clemente	0:4c87cf4af8b5	64	* You can read and write single blocks (CMD17, CMD25) or multiple blocks
clemente	0:4c87cf4af8b5	65	* (CMD18, CMD25). For simplicity, I'll just use single block accesses. When
clemente	0:4c87cf4af8b5	66	* the card gets a read command, it responds with a response token, and then
clemente	0:4c87cf4af8b5	67	* a data token or an error.
clemente	0:4c87cf4af8b5	68	*
clemente	0:4c87cf4af8b5	69	* SPI Command Format
clemente	0:4c87cf4af8b5	70	* ------------------
clemente	0:4c87cf4af8b5	71	* Commands are 6-bytes long, containing the command, 32-bit argument, and CRC.
clemente	0:4c87cf4af8b5	72	*
clemente	0:4c87cf4af8b5	73	* +---------------+------------+------------+-----------+----------+--------------+
clemente	0:4c87cf4af8b5	74	* \| 01 \| cmd[5:0] \| arg[31:24] \| arg[23:16] \| arg[15:8] \| arg[7:0] \| crc[6:0] \| 1 \|
clemente	0:4c87cf4af8b5	75	* +---------------+------------+------------+-----------+----------+--------------+
clemente	0:4c87cf4af8b5	76	*
clemente	0:4c87cf4af8b5	77	* As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95)
clemente	0:4c87cf4af8b5	78	*
clemente	0:4c87cf4af8b5	79	* All Application Specific commands shall be preceded with APP_CMD (CMD55).
clemente	0:4c87cf4af8b5	80	*
clemente	0:4c87cf4af8b5	81	* SPI Response Format
clemente	0:4c87cf4af8b5	82	* -------------------
clemente	0:4c87cf4af8b5	83	* The main response format (R1) is a status byte (normally zero). Key flags:
clemente	0:4c87cf4af8b5	84	* idle - 1 if the card is in an idle state/initialising
clemente	0:4c87cf4af8b5	85	* cmd - 1 if an illegal command code was detected
clemente	0:4c87cf4af8b5	86	*
clemente	0:4c87cf4af8b5	87	* +-------------------------------------------------+
clemente	0:4c87cf4af8b5	88	* R1 \| 0 \| arg \| addr \| seq \| crc \| cmd \| erase \| idle \|
clemente	0:4c87cf4af8b5	89	* +-------------------------------------------------+
clemente	0:4c87cf4af8b5	90	*
clemente	0:4c87cf4af8b5	91	* R1b is the same, except it is followed by a busy signal (zeros) until
clemente	0:4c87cf4af8b5	92	* the first non-zero byte when it is ready again.
clemente	0:4c87cf4af8b5	93	*
clemente	0:4c87cf4af8b5	94	* Data Response Token
clemente	0:4c87cf4af8b5	95	* -------------------
clemente	0:4c87cf4af8b5	96	* Every data block written to the card is acknowledged by a byte
clemente	0:4c87cf4af8b5	97	* response token
clemente	0:4c87cf4af8b5	98	*
clemente	0:4c87cf4af8b5	99	* +----------------------+
clemente	0:4c87cf4af8b5	100	* \| xxx \| 0 \| status \| 1 \|
clemente	0:4c87cf4af8b5	101	* +----------------------+
clemente	0:4c87cf4af8b5	102	* 010 - OK!
clemente	0:4c87cf4af8b5	103	* 101 - CRC Error
clemente	0:4c87cf4af8b5	104	* 110 - Write Error
clemente	0:4c87cf4af8b5	105	*
clemente	0:4c87cf4af8b5	106	* Single Block Read and Write
clemente	0:4c87cf4af8b5	107	* ---------------------------
clemente	0:4c87cf4af8b5	108	*
clemente	0:4c87cf4af8b5	109	* Block transfers have a byte header, followed by the data, followed
clemente	0:4c87cf4af8b5	110	* by a 16-bit CRC. In our case, the data will always be 512 bytes.
clemente	0:4c87cf4af8b5	111	*
clemente	0:4c87cf4af8b5	112	* +------+---------+---------+- - - -+---------+-----------+----------+
clemente	0:4c87cf4af8b5	113	* \| 0xFE \| data[0] \| data[1] \| \| data[n] \| crc[15:8] \| crc[7:0] \|
clemente	0:4c87cf4af8b5	114	* +------+---------+---------+- - - -+---------+-----------+----------+
clemente	0:4c87cf4af8b5	115	*/
clemente	0:4c87cf4af8b5	116
clemente	0:4c87cf4af8b5	117	#include "SDFileSystem.h"
clemente	0:4c87cf4af8b5	118
clemente	0:4c87cf4af8b5	119	#define SD_COMMAND_TIMEOUT 5000
clemente	0:4c87cf4af8b5	120
clemente	0:4c87cf4af8b5	121	SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) :
clemente	0:4c87cf4af8b5	122	FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) {
clemente	0:4c87cf4af8b5	123	_cs = 1;
clemente	0:4c87cf4af8b5	124	}
clemente	0:4c87cf4af8b5	125
clemente	0:4c87cf4af8b5	126	#define R1_IDLE_STATE (1 << 0)
clemente	0:4c87cf4af8b5	127	#define R1_ERASE_RESET (1 << 1)
clemente	0:4c87cf4af8b5	128	#define R1_ILLEGAL_COMMAND (1 << 2)
clemente	0:4c87cf4af8b5	129	#define R1_COM_CRC_ERROR (1 << 3)
clemente	0:4c87cf4af8b5	130	#define R1_ERASE_SEQUENCE_ERROR (1 << 4)
clemente	0:4c87cf4af8b5	131	#define R1_ADDRESS_ERROR (1 << 5)
clemente	0:4c87cf4af8b5	132	#define R1_PARAMETER_ERROR (1 << 6)
clemente	0:4c87cf4af8b5	133
clemente	0:4c87cf4af8b5	134	// Types
clemente	0:4c87cf4af8b5	135	// - v1.x Standard Capacity
clemente	0:4c87cf4af8b5	136	// - v2.x Standard Capacity
clemente	0:4c87cf4af8b5	137	// - v2.x High Capacity
clemente	0:4c87cf4af8b5	138	// - Not recognised as an SD Card
clemente	0:4c87cf4af8b5	139
clemente	0:4c87cf4af8b5	140	#define SDCARD_FAIL 0
clemente	0:4c87cf4af8b5	141	#define SDCARD_V1 1
clemente	0:4c87cf4af8b5	142	#define SDCARD_V2 2
clemente	0:4c87cf4af8b5	143	#define SDCARD_V2HC 3
clemente	0:4c87cf4af8b5	144
clemente	0:4c87cf4af8b5	145	int SDFileSystem::initialise_card() {
clemente	0:4c87cf4af8b5	146	// Set to 100kHz for initialisation, and clock card with cs = 1
clemente	0:4c87cf4af8b5	147	_spi.frequency(100000);
clemente	0:4c87cf4af8b5	148	_cs = 1;
clemente	0:4c87cf4af8b5	149	for(int i=0; i<16; i++) {
clemente	0:4c87cf4af8b5	150	_spi.write(0xFF);
clemente	0:4c87cf4af8b5	151	}
clemente	0:4c87cf4af8b5	152
clemente	0:4c87cf4af8b5	153	// send CMD0, should return with all zeros except IDLE STATE set (bit 0)
clemente	0:4c87cf4af8b5	154	if(_cmd(0, 0) != R1_IDLE_STATE) {
clemente	0:4c87cf4af8b5	155	fprintf(stderr, "No disk, or could not put SD card in to SPI idle state\n");
clemente	0:4c87cf4af8b5	156	return SDCARD_FAIL;
clemente	0:4c87cf4af8b5	157	}
clemente	0:4c87cf4af8b5	158
clemente	0:4c87cf4af8b5	159	// send CMD8 to determine whther it is ver 2.x
clemente	0:4c87cf4af8b5	160	int r = _cmd8();
clemente	0:4c87cf4af8b5	161	if(r == R1_IDLE_STATE) {
clemente	0:4c87cf4af8b5	162	return initialise_card_v2();
clemente	0:4c87cf4af8b5	163	} else if(r == (R1_IDLE_STATE \| R1_ILLEGAL_COMMAND)) {
clemente	0:4c87cf4af8b5	164	return initialise_card_v1();
clemente	0:4c87cf4af8b5	165	} else {
clemente	0:4c87cf4af8b5	166	fprintf(stderr, "Not in idle state after sending CMD8 (not an SD card?)\n");
clemente	0:4c87cf4af8b5	167	return SDCARD_FAIL;
clemente	0:4c87cf4af8b5	168	}
clemente	0:4c87cf4af8b5	169	}
clemente	0:4c87cf4af8b5	170
clemente	0:4c87cf4af8b5	171	int SDFileSystem::initialise_card_v1() {
clemente	0:4c87cf4af8b5	172	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
clemente	0:4c87cf4af8b5	173	_cmd(55, 0);
clemente	0:4c87cf4af8b5	174	if(_cmd(41, 0) == 0) {
clemente	0:4c87cf4af8b5	175	return SDCARD_V1;
clemente	0:4c87cf4af8b5	176	}
clemente	0:4c87cf4af8b5	177	}
clemente	0:4c87cf4af8b5	178
clemente	0:4c87cf4af8b5	179	fprintf(stderr, "Timeout waiting for v1.x card\n");
clemente	0:4c87cf4af8b5	180	return SDCARD_FAIL;
clemente	0:4c87cf4af8b5	181	}
clemente	0:4c87cf4af8b5	182
clemente	0:4c87cf4af8b5	183	int SDFileSystem::initialise_card_v2() {
clemente	0:4c87cf4af8b5	184
clemente	0:4c87cf4af8b5	185	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
clemente	0:4c87cf4af8b5	186	_cmd(55, 0);
clemente	0:4c87cf4af8b5	187	if(_cmd(41, 0) == 0) {
clemente	0:4c87cf4af8b5	188	_cmd58();
clemente	0:4c87cf4af8b5	189	return SDCARD_V2;
clemente	0:4c87cf4af8b5	190	}
clemente	0:4c87cf4af8b5	191	}
clemente	0:4c87cf4af8b5	192
clemente	0:4c87cf4af8b5	193	fprintf(stderr, "Timeout waiting for v2.x card\n");
clemente	0:4c87cf4af8b5	194	return SDCARD_FAIL;
clemente	0:4c87cf4af8b5	195	}
clemente	0:4c87cf4af8b5	196
clemente	0:4c87cf4af8b5	197	int SDFileSystem::disk_initialize() {
clemente	0:4c87cf4af8b5	198
clemente	0:4c87cf4af8b5	199	int i = initialise_card();
clemente	0:4c87cf4af8b5	200	// printf("init card = %d\n", i);
clemente	0:4c87cf4af8b5	201	// printf("OK\n");
clemente	0:4c87cf4af8b5	202
clemente	0:4c87cf4af8b5	203	_sectors = _sd_sectors();
clemente	0:4c87cf4af8b5	204
clemente	0:4c87cf4af8b5	205	// Set block length to 512 (CMD16)
clemente	0:4c87cf4af8b5	206	if(_cmd(16, 512) != 0) {
clemente	0:4c87cf4af8b5	207	fprintf(stderr, "Set 512-byte block timed out\n");
clemente	0:4c87cf4af8b5	208	return 1;
clemente	0:4c87cf4af8b5	209	}
clemente	0:4c87cf4af8b5	210
clemente	0:4c87cf4af8b5	211	_spi.frequency(20000000); // Set to 20MHz for data transfer
clemente	0:4c87cf4af8b5	212	return 0;
clemente	0:4c87cf4af8b5	213	}
clemente	0:4c87cf4af8b5	214
clemente	0:4c87cf4af8b5	215	int SDFileSystem::disk_write(const char *buffer, int block_number) {
clemente	0:4c87cf4af8b5	216	// set write address for single block (CMD24)
clemente	0:4c87cf4af8b5	217	if(_cmd(24, block_number * 512) != 0) {
clemente	0:4c87cf4af8b5	218	return 1;
clemente	0:4c87cf4af8b5	219	}
clemente	0:4c87cf4af8b5	220
clemente	0:4c87cf4af8b5	221	// send the data block
clemente	0:4c87cf4af8b5	222	_write(buffer, 512);
clemente	0:4c87cf4af8b5	223	return 0;
clemente	0:4c87cf4af8b5	224	}
clemente	0:4c87cf4af8b5	225
clemente	0:4c87cf4af8b5	226	int SDFileSystem::disk_read(char *buffer, int block_number) {
clemente	0:4c87cf4af8b5	227	// set read address for single block (CMD17)
clemente	0:4c87cf4af8b5	228	if(_cmd(17, block_number * 512) != 0) {
clemente	0:4c87cf4af8b5	229	return 1;
clemente	0:4c87cf4af8b5	230	}
clemente	0:4c87cf4af8b5	231
clemente	0:4c87cf4af8b5	232	// receive the data
clemente	0:4c87cf4af8b5	233	_read(buffer, 512);
clemente	0:4c87cf4af8b5	234	return 0;
clemente	0:4c87cf4af8b5	235	}
clemente	0:4c87cf4af8b5	236
clemente	0:4c87cf4af8b5	237	int SDFileSystem::disk_status() { return 0; }
clemente	0:4c87cf4af8b5	238	int SDFileSystem::disk_sync() { return 0; }
clemente	0:4c87cf4af8b5	239	int SDFileSystem::disk_sectors() { return _sectors; }
clemente	0:4c87cf4af8b5	240
clemente	0:4c87cf4af8b5	241	// PRIVATE FUNCTIONS
clemente	0:4c87cf4af8b5	242
clemente	0:4c87cf4af8b5	243	int SDFileSystem::_cmd(int cmd, int arg) {
clemente	0:4c87cf4af8b5	244	_cs = 0;
clemente	0:4c87cf4af8b5	245
clemente	0:4c87cf4af8b5	246	// send a command
clemente	0:4c87cf4af8b5	247	_spi.write(0x40 \| cmd);
clemente	0:4c87cf4af8b5	248	_spi.write(arg >> 24);
clemente	0:4c87cf4af8b5	249	_spi.write(arg >> 16);
clemente	0:4c87cf4af8b5	250	_spi.write(arg >> 8);
clemente	0:4c87cf4af8b5	251	_spi.write(arg >> 0);
clemente	0:4c87cf4af8b5	252	_spi.write(0x95);
clemente	0:4c87cf4af8b5	253
clemente	0:4c87cf4af8b5	254	// wait for the repsonse (response[7] == 0)
clemente	0:4c87cf4af8b5	255	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
clemente	0:4c87cf4af8b5	256	int response = _spi.write(0xFF);
clemente	0:4c87cf4af8b5	257	if(!(response & 0x80)) {
clemente	0:4c87cf4af8b5	258	_cs = 1;
clemente	0:4c87cf4af8b5	259	_spi.write(0xFF);
clemente	0:4c87cf4af8b5	260	return response;
clemente	0:4c87cf4af8b5	261	}
clemente	0:4c87cf4af8b5	262	}
clemente	0:4c87cf4af8b5	263	_cs = 1;
clemente	0:4c87cf4af8b5	264	_spi.write(0xFF);
clemente	0:4c87cf4af8b5	265	return -1; // timeout
clemente	0:4c87cf4af8b5	266	}
clemente	0:4c87cf4af8b5	267	int SDFileSystem::_cmdx(int cmd, int arg) {
clemente	0:4c87cf4af8b5	268	_cs = 0;
clemente	0:4c87cf4af8b5	269
clemente	0:4c87cf4af8b5	270	// send a command
clemente	0:4c87cf4af8b5	271	_spi.write(0x40 \| cmd);
clemente	0:4c87cf4af8b5	272	_spi.write(arg >> 24);
clemente	0:4c87cf4af8b5	273	_spi.write(arg >> 16);
clemente	0:4c87cf4af8b5	274	_spi.write(arg >> 8);
clemente	0:4c87cf4af8b5	275	_spi.write(arg >> 0);
clemente	0:4c87cf4af8b5	276	_spi.write(0x95);
clemente	0:4c87cf4af8b5	277
clemente	0:4c87cf4af8b5	278	// wait for the repsonse (response[7] == 0)
clemente	0:4c87cf4af8b5	279	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
clemente	0:4c87cf4af8b5	280	int response = _spi.write(0xFF);
clemente	0:4c87cf4af8b5	281	if(!(response & 0x80)) {
clemente	0:4c87cf4af8b5	282	return response;
clemente	0:4c87cf4af8b5	283	}
clemente	0:4c87cf4af8b5	284	}
clemente	0:4c87cf4af8b5	285	_cs = 1;
clemente	0:4c87cf4af8b5	286	_spi.write(0xFF);
clemente	0:4c87cf4af8b5	287	return -1; // timeout
clemente	0:4c87cf4af8b5	288	}
clemente	0:4c87cf4af8b5	289
clemente	0:4c87cf4af8b5	290
clemente	0:4c87cf4af8b5	291	int SDFileSystem::_cmd58() {
clemente	0:4c87cf4af8b5	292	_cs = 0;
clemente	0:4c87cf4af8b5	293	int arg = 0;
clemente	0:4c87cf4af8b5	294
clemente	0:4c87cf4af8b5	295	// send a command
clemente	0:4c87cf4af8b5	296	_spi.write(0x40 \| 58);
clemente	0:4c87cf4af8b5	297	_spi.write(arg >> 24);
clemente	0:4c87cf4af8b5	298	_spi.write(arg >> 16);
clemente	0:4c87cf4af8b5	299	_spi.write(arg >> 8);
clemente	0:4c87cf4af8b5	300	_spi.write(arg >> 0);
clemente	0:4c87cf4af8b5	301	_spi.write(0x95);
clemente	0:4c87cf4af8b5	302
clemente	0:4c87cf4af8b5	303	// wait for the repsonse (response[7] == 0)
clemente	0:4c87cf4af8b5	304	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
clemente	0:4c87cf4af8b5	305	int response = _spi.write(0xFF);
clemente	0:4c87cf4af8b5	306	if(!(response & 0x80)) {
clemente	0:4c87cf4af8b5	307	int ocr = _spi.write(0xFF) << 24;
clemente	0:4c87cf4af8b5	308	ocr \|= _spi.write(0xFF) << 16;
clemente	0:4c87cf4af8b5	309	ocr \|= _spi.write(0xFF) << 8;
clemente	0:4c87cf4af8b5	310	ocr \|= _spi.write(0xFF) << 0;
clemente	0:4c87cf4af8b5	311	// printf("OCR = 0x%08X\n", ocr);
clemente	0:4c87cf4af8b5	312	_cs = 1;
clemente	0:4c87cf4af8b5	313	_spi.write(0xFF);
clemente	0:4c87cf4af8b5	314	return response;
clemente	0:4c87cf4af8b5	315	}
clemente	0:4c87cf4af8b5	316	}
clemente	0:4c87cf4af8b5	317	_cs = 1;
clemente	0:4c87cf4af8b5	318	_spi.write(0xFF);
clemente	0:4c87cf4af8b5	319	return -1; // timeout
clemente	0:4c87cf4af8b5	320	}
clemente	0:4c87cf4af8b5	321
clemente	0:4c87cf4af8b5	322	int SDFileSystem::_cmd8() {
clemente	0:4c87cf4af8b5	323	_cs = 0;
clemente	0:4c87cf4af8b5	324
clemente	0:4c87cf4af8b5	325	// send a command
clemente	0:4c87cf4af8b5	326	_spi.write(0x40 \| 8); // CMD8
clemente	0:4c87cf4af8b5	327	_spi.write(0x00); // reserved
clemente	0:4c87cf4af8b5	328	_spi.write(0x00); // reserved
clemente	0:4c87cf4af8b5	329	_spi.write(0x01); // 3.3v
clemente	0:4c87cf4af8b5	330	_spi.write(0xAA); // check pattern
clemente	0:4c87cf4af8b5	331	_spi.write(0x87); // crc
clemente	0:4c87cf4af8b5	332
clemente	0:4c87cf4af8b5	333	// wait for the repsonse (response[7] == 0)
clemente	0:4c87cf4af8b5	334	for(int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) {
clemente	0:4c87cf4af8b5	335	char response[5];
clemente	0:4c87cf4af8b5	336	response[0] = _spi.write(0xFF);
clemente	0:4c87cf4af8b5	337	if(!(response[0] & 0x80)) {
clemente	0:4c87cf4af8b5	338	for(int j=1; j<5; j++) {
clemente	0:4c87cf4af8b5	339	response[i] = _spi.write(0xFF);
clemente	0:4c87cf4af8b5	340	}
clemente	0:4c87cf4af8b5	341	_cs = 1;
clemente	0:4c87cf4af8b5	342	_spi.write(0xFF);
clemente	0:4c87cf4af8b5	343	return response[0];
clemente	0:4c87cf4af8b5	344	}
clemente	0:4c87cf4af8b5	345	}
clemente	0:4c87cf4af8b5	346	_cs = 1;
clemente	0:4c87cf4af8b5	347	_spi.write(0xFF);
clemente	0:4c87cf4af8b5	348	return -1; // timeout
clemente	0:4c87cf4af8b5	349	}
clemente	0:4c87cf4af8b5	350
clemente	0:4c87cf4af8b5	351	int SDFileSystem::_read(char *buffer, int length) {
clemente	0:4c87cf4af8b5	352	_cs = 0;
clemente	0:4c87cf4af8b5	353
clemente	0:4c87cf4af8b5	354	// read until start byte (0xFF)
clemente	0:4c87cf4af8b5	355	while(_spi.write(0xFF) != 0xFE);
clemente	0:4c87cf4af8b5	356
clemente	0:4c87cf4af8b5	357	// read data
clemente	0:4c87cf4af8b5	358	for(int i=0; i<length; i++) {
clemente	0:4c87cf4af8b5	359	buffer[i] = _spi.write(0xFF);
clemente	0:4c87cf4af8b5	360	}
clemente	0:4c87cf4af8b5	361	_spi.write(0xFF); // checksum
clemente	0:4c87cf4af8b5	362	_spi.write(0xFF);
clemente	0:4c87cf4af8b5	363
clemente	0:4c87cf4af8b5	364	_cs = 1;
clemente	0:4c87cf4af8b5	365	_spi.write(0xFF);
clemente	0:4c87cf4af8b5	366	return 0;
clemente	0:4c87cf4af8b5	367	}
clemente	0:4c87cf4af8b5	368
clemente	0:4c87cf4af8b5	369	int SDFileSystem::_write(const char *buffer, int length) {
clemente	0:4c87cf4af8b5	370	_cs = 0;
clemente	0:4c87cf4af8b5	371
clemente	0:4c87cf4af8b5	372	// indicate start of block
clemente	0:4c87cf4af8b5	373	_spi.write(0xFE);
clemente	0:4c87cf4af8b5	374
clemente	0:4c87cf4af8b5	375	// write the data
clemente	0:4c87cf4af8b5	376	for(int i=0; i<length; i++) {
clemente	0:4c87cf4af8b5	377	_spi.write(buffer[i]);
clemente	0:4c87cf4af8b5	378	}
clemente	0:4c87cf4af8b5	379
clemente	0:4c87cf4af8b5	380	// write the checksum
clemente	0:4c87cf4af8b5	381	_spi.write(0xFF);
clemente	0:4c87cf4af8b5	382	_spi.write(0xFF);
clemente	0:4c87cf4af8b5	383
clemente	0:4c87cf4af8b5	384	// check the repsonse token
clemente	0:4c87cf4af8b5	385	if((_spi.write(0xFF) & 0x1F) != 0x05) {
clemente	0:4c87cf4af8b5	386	_cs = 1;
clemente	0:4c87cf4af8b5	387	_spi.write(0xFF);
clemente	0:4c87cf4af8b5	388	return 1;
clemente	0:4c87cf4af8b5	389	}
clemente	0:4c87cf4af8b5	390
clemente	0:4c87cf4af8b5	391	// wait for write to finish
clemente	0:4c87cf4af8b5	392	while(_spi.write(0xFF) == 0);
clemente	0:4c87cf4af8b5	393
clemente	0:4c87cf4af8b5	394	_cs = 1;
clemente	0:4c87cf4af8b5	395	_spi.write(0xFF);
clemente	0:4c87cf4af8b5	396	return 0;
clemente	0:4c87cf4af8b5	397	}
clemente	0:4c87cf4af8b5	398
clemente	0:4c87cf4af8b5	399	static int ext_bits(char *data, int msb, int lsb) {
clemente	0:4c87cf4af8b5	400	int bits = 0;
clemente	0:4c87cf4af8b5	401	int size = 1 + msb - lsb;
clemente	0:4c87cf4af8b5	402	for(int i=0; i<size; i++) {
clemente	0:4c87cf4af8b5	403	int position = lsb + i;
clemente	0:4c87cf4af8b5	404	int byte = 15 - (position >> 3);
clemente	0:4c87cf4af8b5	405	int bit = position & 0x7;
clemente	0:4c87cf4af8b5	406	int value = (data[byte] >> bit) & 1;
clemente	0:4c87cf4af8b5	407	bits \|= value << i;
clemente	0:4c87cf4af8b5	408	}
clemente	0:4c87cf4af8b5	409	return bits;
clemente	0:4c87cf4af8b5	410	}
clemente	0:4c87cf4af8b5	411
clemente	0:4c87cf4af8b5	412	int SDFileSystem::_sd_sectors() {
clemente	0:4c87cf4af8b5	413
clemente	0:4c87cf4af8b5	414	// CMD9, Response R2 (R1 byte + 16-byte block read)
clemente	0:4c87cf4af8b5	415	if(_cmdx(9, 0) != 0) {
clemente	0:4c87cf4af8b5	416	fprintf(stderr, "Didn't get a response from the disk\n");
clemente	0:4c87cf4af8b5	417	return 0;
clemente	0:4c87cf4af8b5	418	}
clemente	0:4c87cf4af8b5	419
clemente	0:4c87cf4af8b5	420	char csd[16];
clemente	0:4c87cf4af8b5	421	if(_read(csd, 16) != 0) {
clemente	0:4c87cf4af8b5	422	fprintf(stderr, "Couldn't read csd response from disk\n");
clemente	0:4c87cf4af8b5	423	return 0;
clemente	0:4c87cf4af8b5	424	}
clemente	0:4c87cf4af8b5	425
clemente	0:4c87cf4af8b5	426	// csd_structure : csd[127:126]
clemente	0:4c87cf4af8b5	427	// c_size : csd[73:62]
clemente	0:4c87cf4af8b5	428	// c_size_mult : csd[49:47]
clemente	0:4c87cf4af8b5	429	// read_bl_len : csd[83:80] - the maximum read block length
clemente	0:4c87cf4af8b5	430
clemente	0:4c87cf4af8b5	431	int csd_structure = ext_bits(csd, 127, 126);
clemente	0:4c87cf4af8b5	432	int c_size = ext_bits(csd, 73, 62);
clemente	0:4c87cf4af8b5	433	int c_size_mult = ext_bits(csd, 49, 47);
clemente	0:4c87cf4af8b5	434	int read_bl_len = ext_bits(csd, 83, 80);
clemente	0:4c87cf4af8b5	435
clemente	0:4c87cf4af8b5	436	// printf("CSD_STRUCT = %d\n", csd_structure);
clemente	0:4c87cf4af8b5	437
clemente	0:4c87cf4af8b5	438	if(csd_structure != 0) {
clemente	0:4c87cf4af8b5	439	fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures\n");
clemente	0:4c87cf4af8b5	440	return 0;
clemente	0:4c87cf4af8b5	441	}
clemente	0:4c87cf4af8b5	442
clemente	0:4c87cf4af8b5	443	// memory capacity = BLOCKNR * BLOCK_LEN
clemente	0:4c87cf4af8b5	444	// where
clemente	0:4c87cf4af8b5	445	// BLOCKNR = (C_SIZE+1) * MULT
clemente	0:4c87cf4af8b5	446	// MULT = 2^(C_SIZE_MULT+2) (C_SIZE_MULT < 8)
clemente	0:4c87cf4af8b5	447	// BLOCK_LEN = 2^READ_BL_LEN, (READ_BL_LEN < 12)
clemente	0:4c87cf4af8b5	448
clemente	0:4c87cf4af8b5	449	int block_len = 1 << read_bl_len;
clemente	0:4c87cf4af8b5	450	int mult = 1 << (c_size_mult + 2);
clemente	0:4c87cf4af8b5	451	int blocknr = (c_size + 1) * mult;
clemente	0:4c87cf4af8b5	452	int capacity = blocknr * block_len;
clemente	0:4c87cf4af8b5	453
clemente	0:4c87cf4af8b5	454	int blocks = capacity / 512;
clemente	0:4c87cf4af8b5	455
clemente	0:4c87cf4af8b5	456	return blocks;
clemente	0:4c87cf4af8b5	457	}

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	26 May 2012
Imports:	40
Forks:	0
Commits:	1
Dependents:	0
Dependencies:	2
Followers:	1

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SDFileSystem.cpp@0:4c87cf4af8b5, 2012-05-26 (annotated)

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