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3
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1 |
.nolist
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2 |
.include "m168def.inc" ; Same family as 328P
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3 |
.list
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4 |
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5 |
;; Interrupt Vector
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6 |
.org 0x00
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7 |
rjmp init
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8 |
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9 |
.org SPIaddr
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10 |
rjmp SPI_Interrupt
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11 |
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8
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12 |
.org ADCCaddr
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13 |
rjmp ADC_Interrupt
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14 |
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3
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15 |
;; SPI
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16 |
.equ SPI_DDR = DDRB
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17 |
.equ SPI_PORT = PORTB
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18 |
.equ SPI_SCK = PORTB5
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19 |
.equ SPI_MISO = PORTB4
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20 |
.equ SPI_MOSI = PORTB3
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21 |
.equ SPI_SS = PORTB2
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22 |
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23 |
.equ SPI_FLAGS = GPIOR0
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24 |
.equ SPI_BUSY = 0
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25 |
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26 |
;; Initialize SPI subsystem for master operation
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27 |
SPI_Init:
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28 |
; Set modes
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29 |
sbi SPI_DDR, SPI_SCK ; Out
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30 |
sbi SPI_DDR, SPI_MOSI ; Out
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31 |
sbi SPI_DDR, SPI_SS ; Out
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32 |
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33 |
; Drive SS high (off)
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34 |
sbi SPI_PORT, SPI_SS
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35 |
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36 |
; Set control mode
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37 |
; Enable interrupt
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38 |
; Enable SPI
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39 |
; MSB first
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40 |
; Master mode
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41 |
; Polarity/phase: Mode 0 (sample on rising edge)
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42 |
; Clock rate 1/16
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43 |
ldi r16, (1 << SPIE) | (1 << SPE) | (0 << DORD) | (1 << MSTR) | (0 << CPOL) | (0 << CPHA) | (0b01 << SPR0)
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44 |
out SPCR, r16
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45 |
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46 |
; Flags
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47 |
clr r0
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48 |
out SPI_FLAGS, r0
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49 |
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50 |
; Done
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51 |
ret
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52 |
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53 |
;; Send byte
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54 |
;; Input: r16
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55 |
;; XXX: should not be busy...
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56 |
SPI_Send:
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57 |
; Flag
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58 |
sbi SPI_FLAGS, SPI_BUSY
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59 |
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60 |
; Enable slave (low)
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61 |
cbi SPI_PORT, SPI_SS
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62 |
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63 |
; Write byte (starts SCK)
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64 |
out SPDR, r16
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65 |
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66 |
; Wait for interrupt
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67 |
; Done
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68 |
ret
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69 |
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70 |
;; Wait for byte to be sent
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71 |
SPI_Wait:
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wait_idle:
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73 |
sbic SPI_FLAGS, SPI_BUSY ; Test for busy flag
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74 |
rjmp wait_idle ; loop
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75 |
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76 |
; Done
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77 |
ret
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78 |
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79 |
;; Service SPI interrupt
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80 |
SPI_Interrupt:
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81 |
; Store SREG
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82 |
in r16, SREG
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83 |
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84 |
; Drive SS high (off)
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85 |
sbi SPI_PORT, SPI_SS
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86 |
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87 |
; Flag
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88 |
cbi SPI_FLAGS, SPI_BUSY
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89 |
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90 |
; Done
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91 |
out SREG, r16
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92 |
reti
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93 |
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94 |
;; LCD
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95 |
.equ LCD_DDR = DDRB
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96 |
.equ LCD_PORT = PORTB
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97 |
.equ LCD_OE = PORTB1 ; Output Enable (Low)
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98 |
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99 |
; Output font for 7-segment display
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100 |
LCD_Font:
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101 |
.db 0b00111111, 0b00000110 ; 0, 1
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102 |
.db 0b01011011, 0b01001111 ; 2, 3
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103 |
.db 0b01100110, 0b01101101 ; 4, 5
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104 |
.db 0b01111101, 0b00000111 ; 6, 7
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105 |
.db 0b01111111, 0b01100111 ; 8, 9
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106 |
.db 0b10000000, 0b00000000 ; .,
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107 |
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108 |
;.db 0b00111111, ; 0
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109 |
; 0b00000110, ; 1
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110 |
; 0b01011011, ; 2
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111 |
; 0b01001111, ; 3
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112 |
; 0b01100110, ; 4
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113 |
; 0b01101101, ; 5
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114 |
; 0b01111101, ; 6
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115 |
; 0b00000111, ; 7
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116 |
; 0b01111111, ; 8
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117 |
; 0b01100111, ; 9
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118 |
; 0b10000000, ; .
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119 |
; 0b01000000 ;
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120 |
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121 |
.equ LCD_0 = 0
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122 |
.equ LCD_1 = 1
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.equ LCD_2 = 2
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124 |
.equ LCD_3 = 3
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125 |
.equ LCD_4 = 4
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126 |
.equ LCD_5 = 5
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127 |
.equ LCD_6 = 6
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128 |
.equ LCD_7 = 7
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129 |
.equ LCD_8 = 8
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130 |
.equ LCD_9 = 9
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131 |
.equ LCD_DOT = 10
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132 |
.equ LCD_EMPTY = 11
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133 |
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134 |
;; Initialize LCD to empty, and enable
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LCD_Init:
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136 |
; Setup ENable port
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137 |
sbi LCD_PORT, LCD_OE ; Disabled (Low)
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138 |
sbi LCD_DDR, LCD_OE ; Out
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139 |
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140 |
; empty
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141 |
ldi r16, 0b11111111
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142 |
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143 |
; Output
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144 |
rcall SPI_Send
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145 |
rcall SPI_Wait
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146 |
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147 |
; Enable
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148 |
cbi LCD_PORT, LCD_OE
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149 |
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150 |
; Done
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151 |
ret
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152 |
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153 |
;; Display a single digit on the display
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154 |
;; Input: r16
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155 |
LCD_Show:
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156 |
clr r0, 0
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157 |
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158 |
; Prep address
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159 |
; base addr for font table
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160 |
ldi ZH, high(2*LCD_Font)
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161 |
ldi ZL, low(2*LCD_Font)
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162 |
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163 |
; offset
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164 |
add ZL, r16
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165 |
adc ZH, r0
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166 |
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167 |
; Load char
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168 |
lpm r16, Z
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6
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169 |
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170 |
;; Continue
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3
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171 |
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6
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172 |
;; Display a raw segment mask
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173 |
;; Input: r16
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174 |
LCD_ShowRaw:
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3
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175 |
; Invert
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176 |
com r16
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177 |
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178 |
; Display
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6
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179 |
rjmp SPI_Send
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3
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180 |
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8
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181 |
;; ADC
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182 |
.equ ADC_DDR = DDRC
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183 |
.equ ADC_PORT = PORTC
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184 |
.equ ADC_PIN = PORTC0
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7
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185 |
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8
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186 |
;; Initialize the ADC for starting conversions
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187 |
ADC_Init:
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188 |
; Setup ADMUX
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189 |
; Use AVcc as ref
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190 |
; Left-adjust result (for 8-bit access)
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191 |
; Select ADC0
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192 |
ldi r16, (0b01 << REFS0) | (1 << ADLAR) | (0b000 << MUX0)
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193 |
sts ADMUX, r16
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194 |
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195 |
; Setup ADCSRB
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196 |
; Free-running mode
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197 |
ldi r16, (0b000 << ADTS0)
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198 |
sts ADCSRB, r16
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199 |
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200 |
; Setup ADCSRA
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201 |
; Enable
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202 |
; Start right away...
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203 |
; Auto-trigger
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204 |
; Enable Interrupt
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205 |
; Scale 1/128
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206 |
ldi r16, (1 << ADEN) | (1 << ADSC) | (1 << ADATE) | (1 << ADIE) | (0b111 << ADPS0)
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207 |
sts ADCSRA, r16
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208 |
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209 |
; Disable digital circuit for pin
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210 |
ldi r16, (1 << ADC_PIN)
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211 |
sts DIDR0, r16
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212 |
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213 |
; Debug LED
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214 |
sbi DDRD, PORTD7
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215 |
sbi PORTD, PORTD7
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216 |
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217 |
; Done
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218 |
ret
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219 |
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220 |
ADC_Interrupt:
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221 |
; Off
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222 |
cbi PORTD, PORTD7
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223 |
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224 |
; Done
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225 |
reti
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226 |
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227 |
;; Read the current 8-bit ADC sample
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228 |
; Returns value in r16
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229 |
ADC_Read8:
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230 |
; Copy
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231 |
lds r16, ADCH
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232 |
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233 |
; Done
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234 |
ret
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7
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235 |
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236 |
;; Delay for approx. one second
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4
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237 |
Delay_1s:
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7
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238 |
; 40 * 64k = 2.6M loops
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4
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239 |
ldi r20, 40
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7
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240 |
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241 |
;; Delay for r20 * 64k cycles
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242 |
VarDelay:
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4
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243 |
ldi r21, 255
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7
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244 |
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245 |
;; Delay for r20 * r21 * 255 cycles
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246 |
ShortDelay:
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4
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247 |
ldi r22, 255
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248 |
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249 |
delay:
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250 |
dec r22
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251 |
brne delay
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252 |
dec r21
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253 |
brne delay
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254 |
dec r20
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255 |
brne delay
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256 |
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257 |
ret
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258 |
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7
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259 |
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6
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260 |
;; Count down from 9
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261 |
; Returns once we've hit zero
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262 |
Main_Countdown:
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263 |
; init from 9
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264 |
ldi r24, LCD_9
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265 |
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266 |
loop:
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267 |
; display
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268 |
mov r16, r24
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269 |
rcall LCD_Show
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270 |
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271 |
; exit if zero
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272 |
tst r24
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273 |
ret
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274 |
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275 |
; count down
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276 |
dec r24
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277 |
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278 |
; wait...
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279 |
rcall Delay_1s
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280 |
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281 |
; next
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282 |
rjmp loop
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283 |
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284 |
;; Blink between dot and empty
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285 |
Main_Blink:
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286 |
_blink_loop:
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287 |
; dot
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288 |
ldi r16, LCD_DOT
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289 |
rcall LCD_Show
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290 |
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291 |
; wait...
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292 |
rcall Delay_1s
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293 |
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294 |
; empty
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295 |
ldi r16, LCD_EMPTY
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296 |
rcall LCD_Show
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297 |
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298 |
rcall Delay_1s
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299 |
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300 |
; loop
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301 |
rjmp _blink_loop
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302 |
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303 |
;; Chase segments
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304 |
Main_Spin:
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305 |
_spin_init:
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306 |
; init from top
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307 |
ldi r24, 0b00000001
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308 |
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309 |
_spin_next:
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310 |
; display
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311 |
mov r16, r24
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312 |
rcall LCD_ShowRaw
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313 |
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8
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314 |
; variable delay -> r16
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315 |
rcall ADC_Read8
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316 |
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317 |
; short delay, from ADC
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318 |
mov r20, r16
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319 |
ldi r21, 1
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7
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320 |
rcall ShortDelay
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6
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321 |
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322 |
; next segment
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323 |
lsl r24
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324 |
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325 |
; go back to A if we hit G
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326 |
sbrc r24, 6
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327 |
rjmp _spin_init
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328 |
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329 |
rjmp _spin_next
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4
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330 |
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331 |
Main:
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3
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332 |
init:
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333 |
; Stack
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334 |
ldi r16, high(RAMEND)
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335 |
ldi r17, low(RAMEND)
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336 |
out SPH, r16
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337 |
out SPL, r17
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338 |
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339 |
; Enable interrupts
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340 |
sei
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341 |
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8
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342 |
; ADC (slowest to start up)
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343 |
rcall ADC_Init
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344 |
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3
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345 |
; SPI
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346 |
rcall SPI_Init
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347 |
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8
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348 |
; LCD (requires interrupts, blocks)
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3
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349 |
rcall LCD_Init
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6
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350 |
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351 |
; Run
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352 |
; spin!
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353 |
rcall Main_Spin
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4
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354 |
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355 |
end:
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356 |
rjmp end
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357 |
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