WeatherStation - Web server based weather station using Sparkfun W…

Users » AdamGreen » Code » WeatherStation

Adam Green / Mbed 2 deprecated WeatherStation

Web server based weather station using Sparkfun Weather Meters.

Dependencies: FatFileSystem mbed WeatherMeters SDFileSystem

SDFileSystem/SDFileSystem.cpp@0:616601bde9fb, 2012-02-23 (annotated)

Committer:: AdamGreen
Date:: Thu Feb 23 21:38:39 2012 +0000
Revision:: 0:616601bde9fb

Who changed what in which revision?

User	Revision	Line number	New contents of line
AdamGreen	0:616601bde9fb	1	/* mbed SDFileSystem Library, for providing file access to SD cards
AdamGreen	0:616601bde9fb	2	* Copyright (c) 2008-2010, sford
AdamGreen	0:616601bde9fb	3	*
AdamGreen	0:616601bde9fb	4	* Permission is hereby granted, free of charge, to any person obtaining a copy
AdamGreen	0:616601bde9fb	5	* of this software and associated documentation files (the "Software"), to deal
AdamGreen	0:616601bde9fb	6	* in the Software without restriction, including without limitation the rights
AdamGreen	0:616601bde9fb	7	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
AdamGreen	0:616601bde9fb	8	* copies of the Software, and to permit persons to whom the Software is
AdamGreen	0:616601bde9fb	9	* furnished to do so, subject to the following conditions:
AdamGreen	0:616601bde9fb	10	*
AdamGreen	0:616601bde9fb	11	* The above copyright notice and this permission notice shall be included in
AdamGreen	0:616601bde9fb	12	* all copies or substantial portions of the Software.
AdamGreen	0:616601bde9fb	13	*
AdamGreen	0:616601bde9fb	14	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
AdamGreen	0:616601bde9fb	15	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
AdamGreen	0:616601bde9fb	16	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AdamGreen	0:616601bde9fb	17	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
AdamGreen	0:616601bde9fb	18	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
AdamGreen	0:616601bde9fb	19	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
AdamGreen	0:616601bde9fb	20	* THE SOFTWARE.
AdamGreen	0:616601bde9fb	21	*/
AdamGreen	0:616601bde9fb	22
AdamGreen	0:616601bde9fb	23	/* Introduction
AdamGreen	0:616601bde9fb	24	* ------------
AdamGreen	0:616601bde9fb	25	* SD and MMC cards support a number of interfaces, but common to them all
AdamGreen	0:616601bde9fb	26	* is one based on SPI. This is the one I'm implmenting because it means
AdamGreen	0:616601bde9fb	27	* it is much more portable even though not so performant, and we already
AdamGreen	0:616601bde9fb	28	* have the mbed SPI Interface!
AdamGreen	0:616601bde9fb	29	*
AdamGreen	0:616601bde9fb	30	* The main reference I'm using is Chapter 7, "SPI Mode" of:
AdamGreen	0:616601bde9fb	31	* http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
AdamGreen	0:616601bde9fb	32	*
AdamGreen	0:616601bde9fb	33	* SPI Startup
AdamGreen	0:616601bde9fb	34	* -----------
AdamGreen	0:616601bde9fb	35	* The SD card powers up in SD mode. The SPI interface mode is selected by
AdamGreen	0:616601bde9fb	36	* asserting CS low and sending the reset command (CMD0). The card will
AdamGreen	0:616601bde9fb	37	* respond with a (R1) response.
AdamGreen	0:616601bde9fb	38	*
AdamGreen	0:616601bde9fb	39	* CMD8 is optionally sent to determine the voltage range supported, and
AdamGreen	0:616601bde9fb	40	* indirectly determine whether it is a version 1.x SD/non-SD card or
AdamGreen	0:616601bde9fb	41	* version 2.x. I'll just ignore this for now.
AdamGreen	0:616601bde9fb	42	*
AdamGreen	0:616601bde9fb	43	* ACMD41 is repeatedly issued to initialise the card, until "in idle"
AdamGreen	0:616601bde9fb	44	* (bit 0) of the R1 response goes to '0', indicating it is initialised.
AdamGreen	0:616601bde9fb	45	*
AdamGreen	0:616601bde9fb	46	* You should also indicate whether the host supports High Capicity cards,
AdamGreen	0:616601bde9fb	47	* and check whether the card is high capacity - i'll also ignore this
AdamGreen	0:616601bde9fb	48	*
AdamGreen	0:616601bde9fb	49	* SPI Protocol
AdamGreen	0:616601bde9fb	50	* ------------
AdamGreen	0:616601bde9fb	51	* The SD SPI protocol is based on transactions made up of 8-bit words, with
AdamGreen	0:616601bde9fb	52	* the host starting every bus transaction by asserting the CS signal low. The
AdamGreen	0:616601bde9fb	53	* card always responds to commands, data blocks and errors.
AdamGreen	0:616601bde9fb	54	*
AdamGreen	0:616601bde9fb	55	* The protocol supports a CRC, but by default it is off (except for the
AdamGreen	0:616601bde9fb	56	* first reset CMD0, where the CRC can just be pre-calculated, and CMD8)
AdamGreen	0:616601bde9fb	57	* I'll leave the CRC off I think!
AdamGreen	0:616601bde9fb	58	*
AdamGreen	0:616601bde9fb	59	* Standard capacity cards have variable data block sizes, whereas High
AdamGreen	0:616601bde9fb	60	* Capacity cards fix the size of data block to 512 bytes. I'll therefore
AdamGreen	0:616601bde9fb	61	* just always use the Standard Capacity cards with a block size of 512 bytes.
AdamGreen	0:616601bde9fb	62	* This is set with CMD16.
AdamGreen	0:616601bde9fb	63	*
AdamGreen	0:616601bde9fb	64	* You can read and write single blocks (CMD17, CMD25) or multiple blocks
AdamGreen	0:616601bde9fb	65	* (CMD18, CMD25). For simplicity, I'll just use single block accesses. When
AdamGreen	0:616601bde9fb	66	* the card gets a read command, it responds with a response token, and then
AdamGreen	0:616601bde9fb	67	* a data token or an error.
AdamGreen	0:616601bde9fb	68	*
AdamGreen	0:616601bde9fb	69	* SPI Command Format
AdamGreen	0:616601bde9fb	70	* ------------------
AdamGreen	0:616601bde9fb	71	* Commands are 6-bytes long, containing the command, 32-bit argument, and CRC.
AdamGreen	0:616601bde9fb	72	*
AdamGreen	0:616601bde9fb	73	* +---------------+------------+------------+-----------+----------+--------------+
AdamGreen	0:616601bde9fb	74	* \| 01 \| cmd[5:0] \| arg[31:24] \| arg[23:16] \| arg[15:8] \| arg[7:0] \| crc[6:0] \| 1 \|
AdamGreen	0:616601bde9fb	75	* +---------------+------------+------------+-----------+----------+--------------+
AdamGreen	0:616601bde9fb	76	*
AdamGreen	0:616601bde9fb	77	* As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95)
AdamGreen	0:616601bde9fb	78	*
AdamGreen	0:616601bde9fb	79	* All Application Specific commands shall be preceded with APP_CMD (CMD55).
AdamGreen	0:616601bde9fb	80	*
AdamGreen	0:616601bde9fb	81	* SPI Response Format
AdamGreen	0:616601bde9fb	82	* -------------------
AdamGreen	0:616601bde9fb	83	* The main response format (R1) is a status byte (normally zero). Key flags:
AdamGreen	0:616601bde9fb	84	* idle - 1 if the card is in an idle state/initialising
AdamGreen	0:616601bde9fb	85	* cmd - 1 if an illegal command code was detected
AdamGreen	0:616601bde9fb	86	*
AdamGreen	0:616601bde9fb	87	* +-------------------------------------------------+
AdamGreen	0:616601bde9fb	88	* R1 \| 0 \| arg \| addr \| seq \| crc \| cmd \| erase \| idle \|
AdamGreen	0:616601bde9fb	89	* +-------------------------------------------------+
AdamGreen	0:616601bde9fb	90	*
AdamGreen	0:616601bde9fb	91	* R1b is the same, except it is followed by a busy signal (zeros) until
AdamGreen	0:616601bde9fb	92	* the first non-zero byte when it is ready again.
AdamGreen	0:616601bde9fb	93	*
AdamGreen	0:616601bde9fb	94	* Data Response Token
AdamGreen	0:616601bde9fb	95	* -------------------
AdamGreen	0:616601bde9fb	96	* Every data block written to the card is acknowledged by a byte
AdamGreen	0:616601bde9fb	97	* response token
AdamGreen	0:616601bde9fb	98	*
AdamGreen	0:616601bde9fb	99	* +----------------------+
AdamGreen	0:616601bde9fb	100	* \| xxx \| 0 \| status \| 1 \|
AdamGreen	0:616601bde9fb	101	* +----------------------+
AdamGreen	0:616601bde9fb	102	* 010 - OK!
AdamGreen	0:616601bde9fb	103	* 101 - CRC Error
AdamGreen	0:616601bde9fb	104	* 110 - Write Error
AdamGreen	0:616601bde9fb	105	*
AdamGreen	0:616601bde9fb	106	* Single Block Read and Write
AdamGreen	0:616601bde9fb	107	* ---------------------------
AdamGreen	0:616601bde9fb	108	*
AdamGreen	0:616601bde9fb	109	* Block transfers have a byte header, followed by the data, followed
AdamGreen	0:616601bde9fb	110	* by a 16-bit CRC. In our case, the data will always be 512 bytes.
AdamGreen	0:616601bde9fb	111	*
AdamGreen	0:616601bde9fb	112	* +------+---------+---------+- - - -+---------+-----------+----------+
AdamGreen	0:616601bde9fb	113	* \| 0xFE \| data[0] \| data[1] \| \| data[n] \| crc[15:8] \| crc[7:0] \|
AdamGreen	0:616601bde9fb	114	* +------+---------+---------+- - - -+---------+-----------+----------+
AdamGreen	0:616601bde9fb	115	*/
AdamGreen	0:616601bde9fb	116
AdamGreen	0:616601bde9fb	117	#include "SDFileSystem.h"
AdamGreen	0:616601bde9fb	118
AdamGreen	0:616601bde9fb	119	#define SD_COMMAND_TIMEOUT 5000
AdamGreen	0:616601bde9fb	120
AdamGreen	0:616601bde9fb	121	SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* pName) :
AdamGreen	0:616601bde9fb	122	FATFileSystem(pName), _spi(mosi, miso, sclk), _cs(cs) {
AdamGreen	0:616601bde9fb	123	_cs = 1;
AdamGreen	0:616601bde9fb	124	}
AdamGreen	0:616601bde9fb	125
AdamGreen	0:616601bde9fb	126	#define R1_IDLE_STATE (1 << 0)
AdamGreen	0:616601bde9fb	127	#define R1_ERASE_RESET (1 << 1)
AdamGreen	0:616601bde9fb	128	#define R1_ILLEGAL_COMMAND (1 << 2)
AdamGreen	0:616601bde9fb	129	#define R1_COM_CRC_ERROR (1 << 3)
AdamGreen	0:616601bde9fb	130	#define R1_ERASE_SEQUENCE_ERROR (1 << 4)
AdamGreen	0:616601bde9fb	131	#define R1_ADDRESS_ERROR (1 << 5)
AdamGreen	0:616601bde9fb	132	#define R1_PARAMETER_ERROR (1 << 6)
AdamGreen	0:616601bde9fb	133
AdamGreen	0:616601bde9fb	134	// Types
AdamGreen	0:616601bde9fb	135	// - v1.x Standard Capacity
AdamGreen	0:616601bde9fb	136	// - v2.x Standard Capacity
AdamGreen	0:616601bde9fb	137	// - v2.x High Capacity
AdamGreen	0:616601bde9fb	138	// - Not recognised as an SD Card
AdamGreen	0:616601bde9fb	139
AdamGreen	0:616601bde9fb	140	#define SDCARD_FAIL 0
AdamGreen	0:616601bde9fb	141	#define SDCARD_V1 1
AdamGreen	0:616601bde9fb	142	#define SDCARD_V2 2
AdamGreen	0:616601bde9fb	143	#define SDCARD_V2HC 3
AdamGreen	0:616601bde9fb	144
AdamGreen	0:616601bde9fb	145	int SDFileSystem::initialise_card() {
AdamGreen	0:616601bde9fb	146	// Set to 100kHz for initialisation, and clock card with cs = 1
AdamGreen	0:616601bde9fb	147	_spi.frequency(100000);
AdamGreen	0:616601bde9fb	148	_cs = 1;
AdamGreen	0:616601bde9fb	149	for(int i=0; i<16; i++) {
AdamGreen	0:616601bde9fb	150	_spi.write(0xFF);
AdamGreen	0:616601bde9fb	151	}
AdamGreen	0:616601bde9fb	152
AdamGreen	0:616601bde9fb	153	// send CMD0, should return with all zeros except IDLE STATE set (bit 0)
AdamGreen	0:616601bde9fb	154	if(_cmd(0, 0) != R1_IDLE_STATE) {
AdamGreen	0:616601bde9fb	155	fprintf(stderr, "No disk, or could not put SD card in to SPI idle state\n");
AdamGreen	0:616601bde9fb	156	return SDCARD_FAIL;
AdamGreen	0:616601bde9fb	157	}
AdamGreen	0:616601bde9fb	158
AdamGreen	0:616601bde9fb	159	// send CMD8 to determine whther it is ver 2.x
AdamGreen	0:616601bde9fb	160	int r = _cmd8();
AdamGreen	0:616601bde9fb	161	if(r == R1_IDLE_STATE) {
AdamGreen	0:616601bde9fb	162	return initialise_card_v2();
AdamGreen	0:616601bde9fb	163	} else if(r == (R1_IDLE_STATE \| R1_ILLEGAL_COMMAND)) {
AdamGreen	0:616601bde9fb	164	return initialise_card_v1();
AdamGreen	0:616601bde9fb	165	} else {
AdamGreen	0:616601bde9fb	166	fprintf(stderr, "Not in idle state after sending CMD8 (not an SD card?)\n");
AdamGreen	0:616601bde9fb	167	return SDCARD_FAIL;
AdamGreen	0:616601bde9fb	168	}
AdamGreen	0:616601bde9fb	169	}
AdamGreen	0:616601bde9fb	170
AdamGreen	0:616601bde9fb	171	int SDFileSystem::initialise_card_v1() {
AdamGreen	0:616601bde9fb	172	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
AdamGreen	0:616601bde9fb	173	_cmd(55, 0);
AdamGreen	0:616601bde9fb	174	if(_cmd(41, 0) == 0) {
AdamGreen	0:616601bde9fb	175	return SDCARD_V1;
AdamGreen	0:616601bde9fb	176	}
AdamGreen	0:616601bde9fb	177	}
AdamGreen	0:616601bde9fb	178
AdamGreen	0:616601bde9fb	179	fprintf(stderr, "Timeout waiting for v1.x card\n");
AdamGreen	0:616601bde9fb	180	return SDCARD_FAIL;
AdamGreen	0:616601bde9fb	181	}
AdamGreen	0:616601bde9fb	182
AdamGreen	0:616601bde9fb	183	int SDFileSystem::initialise_card_v2() {
AdamGreen	0:616601bde9fb	184
AdamGreen	0:616601bde9fb	185	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
AdamGreen	0:616601bde9fb	186	_cmd(55, 0);
AdamGreen	0:616601bde9fb	187	if(_cmd(41, 0) == 0) {
AdamGreen	0:616601bde9fb	188	_cmd58();
AdamGreen	0:616601bde9fb	189	return SDCARD_V2;
AdamGreen	0:616601bde9fb	190	}
AdamGreen	0:616601bde9fb	191	}
AdamGreen	0:616601bde9fb	192
AdamGreen	0:616601bde9fb	193	fprintf(stderr, "Timeout waiting for v2.x card\n");
AdamGreen	0:616601bde9fb	194	return SDCARD_FAIL;
AdamGreen	0:616601bde9fb	195	}
AdamGreen	0:616601bde9fb	196
AdamGreen	0:616601bde9fb	197	int SDFileSystem::disk_initialize() {
AdamGreen	0:616601bde9fb	198
AdamGreen	0:616601bde9fb	199	initialise_card();
AdamGreen	0:616601bde9fb	200	// printf("init card = %d\n", i);
AdamGreen	0:616601bde9fb	201	// printf("OK\n");
AdamGreen	0:616601bde9fb	202
AdamGreen	0:616601bde9fb	203	_sectors = _sd_sectors();
AdamGreen	0:616601bde9fb	204
AdamGreen	0:616601bde9fb	205	// Set block length to 512 (CMD16)
AdamGreen	0:616601bde9fb	206	if(_cmd(16, 512) != 0) {
AdamGreen	0:616601bde9fb	207	fprintf(stderr, "Set 512-byte block timed out\n");
AdamGreen	0:616601bde9fb	208	return 1;
AdamGreen	0:616601bde9fb	209	}
AdamGreen	0:616601bde9fb	210
AdamGreen	0:616601bde9fb	211	_spi.frequency(1000000); // Set to 1MHz for data transfer
AdamGreen	0:616601bde9fb	212	return 0;
AdamGreen	0:616601bde9fb	213	}
AdamGreen	0:616601bde9fb	214
AdamGreen	0:616601bde9fb	215	int SDFileSystem::disk_write(const char *buffer, int block_number) {
AdamGreen	0:616601bde9fb	216	// set write address for single block (CMD24)
AdamGreen	0:616601bde9fb	217	if(_cmd(24, block_number * 512) != 0) {
AdamGreen	0:616601bde9fb	218	return 1;
AdamGreen	0:616601bde9fb	219	}
AdamGreen	0:616601bde9fb	220
AdamGreen	0:616601bde9fb	221	// send the data block
AdamGreen	0:616601bde9fb	222	_write(buffer, 512);
AdamGreen	0:616601bde9fb	223	return 0;
AdamGreen	0:616601bde9fb	224	}
AdamGreen	0:616601bde9fb	225
AdamGreen	0:616601bde9fb	226	int SDFileSystem::disk_read(char *buffer, int block_number) {
AdamGreen	0:616601bde9fb	227	// set read address for single block (CMD17)
AdamGreen	0:616601bde9fb	228	if(_cmd(17, block_number * 512) != 0) {
AdamGreen	0:616601bde9fb	229	return 1;
AdamGreen	0:616601bde9fb	230	}
AdamGreen	0:616601bde9fb	231
AdamGreen	0:616601bde9fb	232	// receive the data
AdamGreen	0:616601bde9fb	233	_read(buffer, 512);
AdamGreen	0:616601bde9fb	234	return 0;
AdamGreen	0:616601bde9fb	235	}
AdamGreen	0:616601bde9fb	236
AdamGreen	0:616601bde9fb	237	int SDFileSystem::disk_status() { return 0; }
AdamGreen	0:616601bde9fb	238	int SDFileSystem::disk_sync() { return 0; }
AdamGreen	0:616601bde9fb	239	int SDFileSystem::disk_sectors() { return _sectors; }
AdamGreen	0:616601bde9fb	240
AdamGreen	0:616601bde9fb	241	// PRIVATE FUNCTIONS
AdamGreen	0:616601bde9fb	242
AdamGreen	0:616601bde9fb	243	int SDFileSystem::_cmd(int cmd, int arg) {
AdamGreen	0:616601bde9fb	244	_cs = 0;
AdamGreen	0:616601bde9fb	245
AdamGreen	0:616601bde9fb	246	// send a command
AdamGreen	0:616601bde9fb	247	_spi.write(0x40 \| cmd);
AdamGreen	0:616601bde9fb	248	_spi.write(arg >> 24);
AdamGreen	0:616601bde9fb	249	_spi.write(arg >> 16);
AdamGreen	0:616601bde9fb	250	_spi.write(arg >> 8);
AdamGreen	0:616601bde9fb	251	_spi.write(arg >> 0);
AdamGreen	0:616601bde9fb	252	_spi.write(0x95);
AdamGreen	0:616601bde9fb	253
AdamGreen	0:616601bde9fb	254	// wait for the repsonse (response[7] == 0)
AdamGreen	0:616601bde9fb	255	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
AdamGreen	0:616601bde9fb	256	int response = _spi.write(0xFF);
AdamGreen	0:616601bde9fb	257	if(!(response & 0x80)) {
AdamGreen	0:616601bde9fb	258	_cs = 1;
AdamGreen	0:616601bde9fb	259	_spi.write(0xFF);
AdamGreen	0:616601bde9fb	260	return response;
AdamGreen	0:616601bde9fb	261	}
AdamGreen	0:616601bde9fb	262	}
AdamGreen	0:616601bde9fb	263	_cs = 1;
AdamGreen	0:616601bde9fb	264	_spi.write(0xFF);
AdamGreen	0:616601bde9fb	265	return -1; // timeout
AdamGreen	0:616601bde9fb	266	}
AdamGreen	0:616601bde9fb	267	int SDFileSystem::_cmdx(int cmd, int arg) {
AdamGreen	0:616601bde9fb	268	_cs = 0;
AdamGreen	0:616601bde9fb	269
AdamGreen	0:616601bde9fb	270	// send a command
AdamGreen	0:616601bde9fb	271	_spi.write(0x40 \| cmd);
AdamGreen	0:616601bde9fb	272	_spi.write(arg >> 24);
AdamGreen	0:616601bde9fb	273	_spi.write(arg >> 16);
AdamGreen	0:616601bde9fb	274	_spi.write(arg >> 8);
AdamGreen	0:616601bde9fb	275	_spi.write(arg >> 0);
AdamGreen	0:616601bde9fb	276	_spi.write(0x95);
AdamGreen	0:616601bde9fb	277
AdamGreen	0:616601bde9fb	278	// wait for the repsonse (response[7] == 0)
AdamGreen	0:616601bde9fb	279	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
AdamGreen	0:616601bde9fb	280	int response = _spi.write(0xFF);
AdamGreen	0:616601bde9fb	281	if(!(response & 0x80)) {
AdamGreen	0:616601bde9fb	282	return response;
AdamGreen	0:616601bde9fb	283	}
AdamGreen	0:616601bde9fb	284	}
AdamGreen	0:616601bde9fb	285	_cs = 1;
AdamGreen	0:616601bde9fb	286	_spi.write(0xFF);
AdamGreen	0:616601bde9fb	287	return -1; // timeout
AdamGreen	0:616601bde9fb	288	}
AdamGreen	0:616601bde9fb	289
AdamGreen	0:616601bde9fb	290
AdamGreen	0:616601bde9fb	291	int SDFileSystem::_cmd58() {
AdamGreen	0:616601bde9fb	292	_cs = 0;
AdamGreen	0:616601bde9fb	293	int arg = 0;
AdamGreen	0:616601bde9fb	294
AdamGreen	0:616601bde9fb	295	// send a command
AdamGreen	0:616601bde9fb	296	_spi.write(0x40 \| 58);
AdamGreen	0:616601bde9fb	297	_spi.write(arg >> 24);
AdamGreen	0:616601bde9fb	298	_spi.write(arg >> 16);
AdamGreen	0:616601bde9fb	299	_spi.write(arg >> 8);
AdamGreen	0:616601bde9fb	300	_spi.write(arg >> 0);
AdamGreen	0:616601bde9fb	301	_spi.write(0x95);
AdamGreen	0:616601bde9fb	302
AdamGreen	0:616601bde9fb	303	// wait for the repsonse (response[7] == 0)
AdamGreen	0:616601bde9fb	304	for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
AdamGreen	0:616601bde9fb	305	int response = _spi.write(0xFF);
AdamGreen	0:616601bde9fb	306	if(!(response & 0x80)) {
AdamGreen	0:616601bde9fb	307	int ocr = _spi.write(0xFF) << 24;
AdamGreen	0:616601bde9fb	308	ocr \|= _spi.write(0xFF) << 16;
AdamGreen	0:616601bde9fb	309	ocr \|= _spi.write(0xFF) << 8;
AdamGreen	0:616601bde9fb	310	ocr \|= _spi.write(0xFF) << 0;
AdamGreen	0:616601bde9fb	311	// printf("OCR = 0x%08X\n", ocr);
AdamGreen	0:616601bde9fb	312	_cs = 1;
AdamGreen	0:616601bde9fb	313	_spi.write(0xFF);
AdamGreen	0:616601bde9fb	314	return response;
AdamGreen	0:616601bde9fb	315	}
AdamGreen	0:616601bde9fb	316	}
AdamGreen	0:616601bde9fb	317	_cs = 1;
AdamGreen	0:616601bde9fb	318	_spi.write(0xFF);
AdamGreen	0:616601bde9fb	319	return -1; // timeout
AdamGreen	0:616601bde9fb	320	}
AdamGreen	0:616601bde9fb	321
AdamGreen	0:616601bde9fb	322	int SDFileSystem::_cmd8() {
AdamGreen	0:616601bde9fb	323	_cs = 0;
AdamGreen	0:616601bde9fb	324
AdamGreen	0:616601bde9fb	325	// send a command
AdamGreen	0:616601bde9fb	326	_spi.write(0x40 \| 8); // CMD8
AdamGreen	0:616601bde9fb	327	_spi.write(0x00); // reserved
AdamGreen	0:616601bde9fb	328	_spi.write(0x00); // reserved
AdamGreen	0:616601bde9fb	329	_spi.write(0x01); // 3.3v
AdamGreen	0:616601bde9fb	330	_spi.write(0xAA); // check pattern
AdamGreen	0:616601bde9fb	331	_spi.write(0x87); // crc
AdamGreen	0:616601bde9fb	332
AdamGreen	0:616601bde9fb	333	// wait for the repsonse (response[7] == 0)
AdamGreen	0:616601bde9fb	334	for(int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) {
AdamGreen	0:616601bde9fb	335	char response[5];
AdamGreen	0:616601bde9fb	336	response[0] = _spi.write(0xFF);
AdamGreen	0:616601bde9fb	337	if(!(response[0] & 0x80)) {
AdamGreen	0:616601bde9fb	338	for(int j=1; j<5; j++) {
AdamGreen	0:616601bde9fb	339	response[i] = _spi.write(0xFF);
AdamGreen	0:616601bde9fb	340	}
AdamGreen	0:616601bde9fb	341	_cs = 1;
AdamGreen	0:616601bde9fb	342	_spi.write(0xFF);
AdamGreen	0:616601bde9fb	343	return response[0];
AdamGreen	0:616601bde9fb	344	}
AdamGreen	0:616601bde9fb	345	}
AdamGreen	0:616601bde9fb	346	_cs = 1;
AdamGreen	0:616601bde9fb	347	_spi.write(0xFF);
AdamGreen	0:616601bde9fb	348	return -1; // timeout
AdamGreen	0:616601bde9fb	349	}
AdamGreen	0:616601bde9fb	350
AdamGreen	0:616601bde9fb	351	int SDFileSystem::_read(char *buffer, int length) {
AdamGreen	0:616601bde9fb	352	_cs = 0;
AdamGreen	0:616601bde9fb	353
AdamGreen	0:616601bde9fb	354	// read until start byte (0xFF)
AdamGreen	0:616601bde9fb	355	while(_spi.write(0xFF) != 0xFE);
AdamGreen	0:616601bde9fb	356
AdamGreen	0:616601bde9fb	357	// read data
AdamGreen	0:616601bde9fb	358	for(int i=0; i<length; i++) {
AdamGreen	0:616601bde9fb	359	buffer[i] = _spi.write(0xFF);
AdamGreen	0:616601bde9fb	360	}
AdamGreen	0:616601bde9fb	361	_spi.write(0xFF); // checksum
AdamGreen	0:616601bde9fb	362	_spi.write(0xFF);
AdamGreen	0:616601bde9fb	363
AdamGreen	0:616601bde9fb	364	_cs = 1;
AdamGreen	0:616601bde9fb	365	_spi.write(0xFF);
AdamGreen	0:616601bde9fb	366	return 0;
AdamGreen	0:616601bde9fb	367	}
AdamGreen	0:616601bde9fb	368
AdamGreen	0:616601bde9fb	369	int SDFileSystem::_write(const char *buffer, int length) {
AdamGreen	0:616601bde9fb	370	_cs = 0;
AdamGreen	0:616601bde9fb	371
AdamGreen	0:616601bde9fb	372	// indicate start of block
AdamGreen	0:616601bde9fb	373	_spi.write(0xFE);
AdamGreen	0:616601bde9fb	374
AdamGreen	0:616601bde9fb	375	// write the data
AdamGreen	0:616601bde9fb	376	for(int i=0; i<length; i++) {
AdamGreen	0:616601bde9fb	377	_spi.write(buffer[i]);
AdamGreen	0:616601bde9fb	378	}
AdamGreen	0:616601bde9fb	379
AdamGreen	0:616601bde9fb	380	// write the checksum
AdamGreen	0:616601bde9fb	381	_spi.write(0xFF);
AdamGreen	0:616601bde9fb	382	_spi.write(0xFF);
AdamGreen	0:616601bde9fb	383
AdamGreen	0:616601bde9fb	384	// check the repsonse token
AdamGreen	0:616601bde9fb	385	if((_spi.write(0xFF) & 0x1F) != 0x05) {
AdamGreen	0:616601bde9fb	386	_cs = 1;
AdamGreen	0:616601bde9fb	387	_spi.write(0xFF);
AdamGreen	0:616601bde9fb	388	return 1;
AdamGreen	0:616601bde9fb	389	}
AdamGreen	0:616601bde9fb	390
AdamGreen	0:616601bde9fb	391	// wait for write to finish
AdamGreen	0:616601bde9fb	392	while(_spi.write(0xFF) == 0);
AdamGreen	0:616601bde9fb	393
AdamGreen	0:616601bde9fb	394	_cs = 1;
AdamGreen	0:616601bde9fb	395	_spi.write(0xFF);
AdamGreen	0:616601bde9fb	396	return 0;
AdamGreen	0:616601bde9fb	397	}
AdamGreen	0:616601bde9fb	398
AdamGreen	0:616601bde9fb	399	static int ext_bits(char *data, int msb, int lsb) {
AdamGreen	0:616601bde9fb	400	int bits = 0;
AdamGreen	0:616601bde9fb	401	int size = 1 + msb - lsb;
AdamGreen	0:616601bde9fb	402	for(int i=0; i<size; i++) {
AdamGreen	0:616601bde9fb	403	int position = lsb + i;
AdamGreen	0:616601bde9fb	404	int byte = 15 - (position >> 3);
AdamGreen	0:616601bde9fb	405	int bit = position & 0x7;
AdamGreen	0:616601bde9fb	406	int value = (data[byte] >> bit) & 1;
AdamGreen	0:616601bde9fb	407	bits \|= value << i;
AdamGreen	0:616601bde9fb	408	}
AdamGreen	0:616601bde9fb	409	return bits;
AdamGreen	0:616601bde9fb	410	}
AdamGreen	0:616601bde9fb	411
AdamGreen	0:616601bde9fb	412	int SDFileSystem::_sd_sectors() {
AdamGreen	0:616601bde9fb	413
AdamGreen	0:616601bde9fb	414	// CMD9, Response R2 (R1 byte + 16-byte block read)
AdamGreen	0:616601bde9fb	415	if(_cmdx(9, 0) != 0) {
AdamGreen	0:616601bde9fb	416	fprintf(stderr, "Didn't get a response from the disk\n");
AdamGreen	0:616601bde9fb	417	return 0;
AdamGreen	0:616601bde9fb	418	}
AdamGreen	0:616601bde9fb	419
AdamGreen	0:616601bde9fb	420	char csd[16];
AdamGreen	0:616601bde9fb	421	if(_read(csd, 16) != 0) {
AdamGreen	0:616601bde9fb	422	fprintf(stderr, "Couldn't read csd response from disk\n");
AdamGreen	0:616601bde9fb	423	return 0;
AdamGreen	0:616601bde9fb	424	}
AdamGreen	0:616601bde9fb	425
AdamGreen	0:616601bde9fb	426	// csd_structure : csd[127:126]
AdamGreen	0:616601bde9fb	427	// c_size : csd[73:62]
AdamGreen	0:616601bde9fb	428	// c_size_mult : csd[49:47]
AdamGreen	0:616601bde9fb	429	// read_bl_len : csd[83:80] - the maximum read block length
AdamGreen	0:616601bde9fb	430
AdamGreen	0:616601bde9fb	431	int csd_structure = ext_bits(csd, 127, 126);
AdamGreen	0:616601bde9fb	432	int c_size = ext_bits(csd, 73, 62);
AdamGreen	0:616601bde9fb	433	int c_size_mult = ext_bits(csd, 49, 47);
AdamGreen	0:616601bde9fb	434	int read_bl_len = ext_bits(csd, 83, 80);
AdamGreen	0:616601bde9fb	435
AdamGreen	0:616601bde9fb	436	// printf("CSD_STRUCT = %d\n", csd_structure);
AdamGreen	0:616601bde9fb	437
AdamGreen	0:616601bde9fb	438	if(csd_structure != 0) {
AdamGreen	0:616601bde9fb	439	fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures\n");
AdamGreen	0:616601bde9fb	440	return 0;
AdamGreen	0:616601bde9fb	441	}
AdamGreen	0:616601bde9fb	442
AdamGreen	0:616601bde9fb	443	// memory capacity = BLOCKNR * BLOCK_LEN
AdamGreen	0:616601bde9fb	444	// where
AdamGreen	0:616601bde9fb	445	// BLOCKNR = (C_SIZE+1) * MULT
AdamGreen	0:616601bde9fb	446	// MULT = 2^(C_SIZE_MULT+2) (C_SIZE_MULT < 8)
AdamGreen	0:616601bde9fb	447	// BLOCK_LEN = 2^READ_BL_LEN, (READ_BL_LEN < 12)
AdamGreen	0:616601bde9fb	448
AdamGreen	0:616601bde9fb	449	int block_len = 1 << read_bl_len;
AdamGreen	0:616601bde9fb	450	int mult = 1 << (c_size_mult + 2);
AdamGreen	0:616601bde9fb	451	int blocknr = (c_size + 1) * mult;
AdamGreen	0:616601bde9fb	452	int capacity = blocknr * block_len;
AdamGreen	0:616601bde9fb	453
AdamGreen	0:616601bde9fb	454	int blocks = capacity / 512;
AdamGreen	0:616601bde9fb	455
AdamGreen	0:616601bde9fb	456	return blocks;
AdamGreen	0:616601bde9fb	457	}

Repository toolbox

Export to desktop IDE

Build repository

Repository details

Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	23 Feb 2012
Imports:	113
Forks:	0
Commits:	2
Dependents:	0
Dependencies:	4
Followers:	6

SDFileSystem/SDFileSystem.cpp@0:616601bde9fb, 2012-02-23 (annotated)

Who changed what in which revision?

Repository toolbox

Repository details

Important Information for this Arm website

Access Warning