256 lines
7.2 KiB
C
256 lines
7.2 KiB
C
/*-----------------------------------------------------------------------*/
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/* Low level disk I/O module skeleton for Petit FatFs (C)ChaN, 2014 */
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/* */
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/* ... completed by ... */
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/* */
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/* PFF - Low level disk control module for AVR (C)ChaN, 2014 */
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/* File avr_mmcp.c, part of avr/ in pffsample, a package with sample */
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/* implementations on http://elm-chan.org/fsw/ff/00index_p.html */
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/*-----------------------------------------------------------------------*/
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/* Changes for Teacup see pff.c. */
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#include "pff_diskio.h"
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#ifdef SD
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#include <stdlib.h>
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#include "spi.h"
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#include "delay.h"
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/* Definitions for MMC/SDC command. */
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#define CMD0 (0x40 + 0) /* GO_IDLE_STATE */
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#define CMD1 (0x40 + 1) /* SEND_OP_COND (MMC) */
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#define ACMD41 (0xC0 + 41) /* SEND_OP_COND (SDC) */
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#define CMD8 (0x40 + 8) /* SEND_IF_COND */
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#define CMD16 (0x40 + 16) /* SET_BLOCKLEN */
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#define CMD17 (0x40 + 17) /* READ_SINGLE_BLOCK */
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#define CMD24 (0x40 + 24) /* WRITE_BLOCK */
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#define CMD55 (0x40 + 55) /* APP_CMD */
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#define CMD58 (0x40 + 58) /* READ_OCR */
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/* Card type flags (card_type). */
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#define CT_MMC 0x01 /* MMC ver 3 */
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#define CT_SD1 0x02 /* SD ver 1 */
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#define CT_SD2 0x04 /* SD ver 2 */
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#define CT_BLOCK 0x08 /* Block addressing */
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static BYTE card_type; /* Card type flags. */
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/** Send a command packet to MMC/SD card.
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\param cmd Command.
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\param arg Argument (32 bit).
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\return response byte (bit 7 == 1: send failed).
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*/
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static BYTE send_cmd(BYTE cmd, DWORD arg) {
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BYTE n, res;
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if (cmd & 0x80) { /* ACMD<n> is the command sequence of CMD55-CMD<n>. */
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cmd &= 0x7F;
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res = send_cmd(CMD55, 0);
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if (res > 1)
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return res;
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}
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/* Select the card */
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spi_deselect_sd();
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spi_rw(0xFF);
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spi_select_sd();
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spi_rw(0xFF);
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/* Send command packet */
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spi_rw(cmd); /* Start + Command index */
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spi_rw((BYTE)(arg >> 24)); /* Argument[31..24] */
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spi_rw((BYTE)(arg >> 16)); /* Argument[23..16] */
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spi_rw((BYTE)(arg >> 8)); /* Argument[15..8] */
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spi_rw((BYTE)arg); /* Argument[7..0] */
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n = 0x01; /* Dummy CRC + Stop */
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if (cmd == CMD0) n = 0x95; /* Valid CRC for CMD0(0) + Stop */
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if (cmd == CMD8) n = 0x87; /* Valid CRC for CMD8(0x1AA) Stop */
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spi_rw(n);
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/* Receive command response */
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n = 10; /* Wait for a response, try 10 times. */
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do {
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res = spi_rw(0xFF);
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n--;
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} while ((res & 0x80) && n);
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return res;
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}
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/** Initialize disk drive.
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\return 0 on success, else STA_NOINIT.
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Initialize disk drive and also find out which kind of card we're talking to.
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Description about what's going on here see
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http://elm-chan.org/docs/mmc/mmc_e.html, center section.
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*/
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DSTATUS disk_initialize(void) {
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BYTE n, cmd, ty, ocr[4];
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UINT timeout;
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spi_deselect_sd();
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spi_speed_100_400();
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for (n = 10; n; n--) /* 80 dummy clocks with CS = high. */
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spi_rw(0xFF);
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/* Find card type: MMCv3, SDv1 or SDv2. */
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ty = 0;
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if (send_cmd(CMD0, 0) == 1) { /* Software reset, enter idle state. */
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if (send_cmd(CMD8, 0x1AA) == 1) { /* SDv2? (rejected on others) */
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for (n = 0; n < 4; n++) /* Get trailing return value of R7. */
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ocr[n] = spi_rw(0xFF);
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if (ocr[2] == 0x01 && ocr[3] == 0xAA) {
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/* The card can work at Vdd range of 2.7 - 3.6V. */
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/* Wait for leaving idle state (ACMD41 with HCS bit). */
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for (timeout = 10000; timeout && send_cmd(ACMD41, 1UL << 30); timeout--)
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delay_us(100);
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/* Find out wether it's a block device (CCS bit in OCR). */
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if (timeout && send_cmd(CMD58, 0) == 0) {
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for (n = 0; n < 4; n++)
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ocr[n] = spi_rw(0xFF);
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ty = (ocr[0] & 0x40) ? CT_SD2 | CT_BLOCK : CT_SD2; /* SDv2 */
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}
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}
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}
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else { /* SDv1 or MMCv3 */
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if (send_cmd(ACMD41, 0) <= 1) {
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ty = CT_SD1; cmd = ACMD41; /* SDv1 */
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}
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else {
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ty = CT_MMC; cmd = CMD1; /* MMCv3 */
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}
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/* Wait for leaving idle state. */
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for (timeout = 10000; timeout && send_cmd(cmd, 0); timeout--)
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delay_us(100);
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/* Set R/W block length to 512. */
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if ( ! timeout || send_cmd(CMD16, 512) != 0)
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ty = 0;
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}
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}
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card_type = ty;
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spi_deselect_sd();
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spi_rw(0xFF);
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return ty ? 0 : STA_NOINIT;
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}
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/** Read partial sector.
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\param buffer Received data should go in here.
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\param sector Sector number (LBA).
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\param offset Offset into the sector.
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\param count Byte count (bit 15: destination).
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\return RES_OK on success, else RES_ERROR.
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This is the main reading function. Forming this into directory listings,
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file reads and such stuff is done by Petit FatFs it's self.
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Description about what's going on here see
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http://elm-chan.org/docs/mmc/mmc_e.html, bottom section.
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*/
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#if _USE_READ
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DRESULT disk_readp(BYTE* buffer, DWORD sector, UINT offset, UINT count) {
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DRESULT result;
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BYTE token = 0xFF;
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uint16_t timeout;
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UINT trailing = 514 - offset - count; /* 514 = block size + 2 bytes CRC */
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/* Convert to byte address on non-block cards. */
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if ( ! (card_type & CT_BLOCK))
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sector *= 512;
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/* Read one sector, copy only as many bytes as required. */
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result = RES_ERROR;
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spi_speed_max();
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if (send_cmd(CMD17, sector) == 0) { /* Read single block. */
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/* Wait for data packet. */
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for (timeout = 40000; timeout && (token == 0xFF); timeout--)
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token = spi_rw(0xFF);
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if (token == 0xFE) { /* Valid data arrived. */
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/* Skip leading bytes. */
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while (offset--)
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spi_rw(0xFF);
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/* Receive the requested part of the sector. */
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do {
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/**
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Note that this isn't optimised for performance. The increment and
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the dereferencing could be done while waiting for the SPIF bit
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to become set in spi_rw(). See http://www.matuschek.net/atmega-spi/.
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*/
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*buffer++ = spi_rw(0xFF);
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} while (--count);
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/* Skip trailing bytes and CRC. */
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while (trailing--)
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spi_rw(0xFF);
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result = RES_OK;
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}
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}
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spi_deselect_sd(); /* Every send_cmd() selects. */
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spi_rw(0xFF);
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return result;
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}
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#endif /* _USE_READ */
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/** Write partial pector.
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\param buff Pointer to the data to be written.
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NULL: Initiate/Finalize write operation.
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\param sc Sector number (LBA) or number of bytes to send.
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\return RES_OK on success, else RES_ERROR.
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This is the main writing function. Forming this into file writes and such
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stuff is done by Petit FatFs it's self.
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Description about what's going on here see
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http://elm-chan.org/docs/mmc/mmc_e.html, bottom section.
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*/
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#if _USE_WRITE
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DRESULT disk_writep(const BYTE* buff, DWORD sc) {
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#error disk_writep() not yet implemented
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DRESULT res;
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if ( ! buff) {
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if (sc) {
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// Initiate write process
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}
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else {
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// Finalize write process
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}
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}
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else {
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// Send data to the disk
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}
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return res;
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}
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#endif /* _USE_WRITE */
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#endif /* SD */
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