pikeyd165 – Blame information for rev 1
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1 | office | 1 | // spiram.c |
2 | // |
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3 | // Little library for accessing SPI RAM such as 23K256-I/P |
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4 | // using bcm2835 library on Raspberry Pi |
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5 | // |
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6 | // Author: Mike McCauley |
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7 | // Copyright (C) 2018 Mike McCauley |
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8 | // This software is part of the bcm2835 library and is licensed under the same conditions |
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9 | // $Id: $ |
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10 | |||
11 | #include <bcm2835.h> |
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12 | #include <string.h> // memcpy |
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13 | #include "spiram.h" |
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14 | |||
15 | static uint8_t _mode = SPIRAM_MODE_INVALID; |
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16 | |||
17 | uint8_t spiram_read_sr() |
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18 | { |
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19 | uint8_t command[] = { SPIRAM_OPCODE_READ_SR, 0}; |
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20 | bcm2835_spi_transfern(command, sizeof(command)); |
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21 | return command[1]; |
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22 | } |
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23 | |||
24 | bool spiram_write_sr(uint8_t value) |
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25 | { |
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26 | uint8_t command[] = { SPIRAM_OPCODE_WRITE_SR, value}; |
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27 | bcm2835_spi_transfern(command, sizeof(command)); |
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28 | return true; |
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29 | } |
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30 | |||
31 | bool spiram_set_mode(uint8_t mode) |
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32 | { |
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33 | if (mode != _mode) |
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34 | { |
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35 | spiram_write_sr(mode); |
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36 | _mode = mode; |
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37 | } |
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38 | return true; |
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39 | } |
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40 | |||
41 | bool spiram_begin() |
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42 | { |
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43 | _mode = SPIRAM_MODE_BYTE; |
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44 | |||
45 | bcm2835_spi_setBitOrder(BCM2835_SPI_BIT_ORDER_MSBFIRST); // The default |
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46 | bcm2835_spi_setDataMode(BCM2835_SPI_MODE0); // The default |
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47 | bcm2835_spi_setClockDivider(BCM2835_SPI_CLOCK_DIVIDER_65536); // The default |
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48 | bcm2835_spi_chipSelect(BCM2835_SPI_CS0); // The default |
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49 | bcm2835_spi_setChipSelectPolarity(BCM2835_SPI_CS0, LOW); // the default |
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50 | return true; |
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51 | } |
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52 | |||
53 | bool spiram_end() |
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54 | { |
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55 | bcm2835_spi_end(); |
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56 | return true; |
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57 | } |
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58 | |||
59 | |||
60 | uint8_t spiram_read_byte(uint16_t address) |
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61 | { |
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62 | spiram_set_mode(SPIRAM_MODE_BYTE); |
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63 | uint8_t command[] = { SPIRAM_OPCODE_READ, (address >> 8) & 0xff, address & 0xff, 0xff }; |
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64 | bcm2835_spi_transfern(command, sizeof(command)); |
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65 | uint8_t ret = command[3]; |
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66 | } |
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67 | |||
68 | bool spiram_write_byte(uint16_t address, uint8_t value) |
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69 | { |
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70 | spiram_set_mode(SPIRAM_MODE_BYTE); |
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71 | uint8_t command[] = { SPIRAM_OPCODE_WRITE, (address >> 8) & 0xff, address & 0xff, value }; |
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72 | bcm2835_spi_writenb(command, sizeof(command)); |
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73 | return true; |
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74 | } |
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75 | |||
76 | bool spiram_read_page(uint16_t address, uint8_t *buf) |
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77 | { |
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78 | spiram_set_mode(SPIRAM_MODE_PAGE); |
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79 | uint8_t command[3 + SPIRAM_PAGE_SIZE] = { SPIRAM_OPCODE_READ, (address >> 8) & 0xff, address & 0xff }; |
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80 | bcm2835_spi_transfern(command, sizeof(command)); |
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81 | memcpy(buf, command + 3, SPIRAM_PAGE_SIZE); |
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82 | return true; |
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83 | } |
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84 | |||
85 | bool spiram_write_page(uint16_t address, uint8_t *buf) |
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86 | { |
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87 | spiram_set_mode(SPIRAM_MODE_PAGE); |
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88 | uint8_t command[3 + SPIRAM_PAGE_SIZE] = { SPIRAM_OPCODE_WRITE, (address >> 8) & 0xff, address & 0xff }; |
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89 | memcpy(command + 3, buf, SPIRAM_PAGE_SIZE);; |
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90 | bcm2835_spi_writenb(command, sizeof(command)); |
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91 | return true; |
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92 | } |