Root/
| Source at commit bf2e2c30463d22b5e34fa795eb98b35a855d90ae created 11 years 1 hour ago. By Werner Almesberger, tornado/led/led.cmp: update for new components and changed references | |
|---|---|
| 1 | /* |
| 2 | * fw/mmc-hw.c - MMC hardware interface |
| 3 | * |
| 4 | * Written 2012 by Werner Almesberger |
| 5 | * Copyright 2012 Werner Almesberger |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License as published by |
| 9 | * the Free Software Foundation; either version 2 of the License, or |
| 10 | * (at your option) any later version. |
| 11 | */ |
| 12 | |
| 13 | |
| 14 | #include <stdint.h> |
| 15 | |
| 16 | #include "io.h" |
| 17 | #include "delay.h" |
| 18 | #include "mmc-hw.h" |
| 19 | |
| 20 | |
| 21 | /* |
| 22 | * Pin assignment from |
| 23 | * http://alumni.cs.ucr.edu/~amitra/sdcard/ProdManualSDCardv1.9.pdf |
| 24 | * |
| 25 | * Pin SD mode SPI mode |
| 26 | * 1 DAT3 Chip Select (active low) |
| 27 | * 2 CMD MOSI |
| 28 | * 3 VSS VSS |
| 29 | * 4 VDD VDD |
| 30 | * 5 CLK Clock |
| 31 | * 6 VSS VSS |
| 32 | * 7 DAT0 MISO |
| 33 | */ |
| 34 | |
| 35 | |
| 36 | #define MMC_nCS CARD_DAT3 |
| 37 | #define MMC_MOSI CARD_CMD |
| 38 | #define MMC_CLK CARD_CLK |
| 39 | #define MMC_MISO CARD_DAT0 |
| 40 | |
| 41 | |
| 42 | void mmc_select(void) |
| 43 | { |
| 44 | CLR(MMC_nCS); |
| 45 | } |
| 46 | |
| 47 | void mmc_deselect(void) |
| 48 | { |
| 49 | SET(MMC_nCS); |
| 50 | } |
| 51 | |
| 52 | |
| 53 | uint8_t mmc_recv(void) |
| 54 | { |
| 55 | uint8_t i, v = 0; |
| 56 | |
| 57 | SET(MMC_MOSI); |
| 58 | for (i = 0; i != 8; i++) { |
| 59 | SET(MMC_CLK); |
| 60 | v = (v << 1) | PIN(MMC_MISO); |
| 61 | CLR(MMC_CLK); |
| 62 | } |
| 63 | return v; |
| 64 | } |
| 65 | |
| 66 | |
| 67 | void mmc_send(uint8_t v) |
| 68 | { |
| 69 | uint8_t i; |
| 70 | |
| 71 | for (i = 0; i != 8; i++) { |
| 72 | if (v & 0x80) |
| 73 | SET(MMC_MOSI); |
| 74 | else |
| 75 | CLR(MMC_MOSI); |
| 76 | SET(MMC_CLK); |
| 77 | CLR(MMC_CLK); |
| 78 | v <<= 1; |
| 79 | } |
| 80 | } |
| 81 | |
| 82 | |
| 83 | void mmc_activate(void) |
| 84 | { |
| 85 | SET(MMC_nCS); |
| 86 | CLR(MMC_CLK); |
| 87 | OUT(MMC_nCS); |
| 88 | SET(MMC_MOSI); |
| 89 | SET(MMC_CLK); /* for pre-charging */ |
| 90 | OUT(MMC_MOSI); |
| 91 | OUT(MMC_CLK); |
| 92 | IN(MMC_MISO); |
| 93 | |
| 94 | _delay_ms(100); /* allow card to pre-charge, to limit inrush current */ |
| 95 | |
| 96 | CLR(CARD_nPWR); |
| 97 | |
| 98 | _delay_ms(10); |
| 99 | } |
| 100 | |
| 101 | |
| 102 | void mmc_deactivate(void) |
| 103 | { |
| 104 | CLR(MMC_CLK); |
| 105 | CLR(MMC_nCS); |
| 106 | CLR(MMC_MOSI); |
| 107 | CLR(MMC_MISO); |
| 108 | |
| 109 | SET(CARD_nPWR); |
| 110 | _delay_ms(10); |
| 111 | |
| 112 | OUT(MMC_MISO); |
| 113 | } |
| 114 | |
Branches:
master
tornado-v1
