8dd90cb3 |
1 | #include <hidef.h> |
2 | |
3 | #include "derivative.h" |
4 | #include "MC9S12XS128.h" |
5 | |
6 | /* laziness */ |
7 | #define null16 0x0000 |
8 | #define null8 0x00 |
9 | |
10 | /* x, y, z enum */ |
11 | typedef enum { X, Y, Z } axis; |
12 | |
13 | /* gets magnetic field gauss val from lsm |
14 | * over spi & parses into passed int ptr |
15 | */ |
16 | void read_axis(axis x, int *hi, int *lo) { |
17 | |
18 | switch(x) { |
19 | |
20 | case X: |
21 | |
22 | SPI0DR = 0x8900; |
23 | while(!SPI0SR_SPTEF); |
24 | *hi = SPI0DRL; |
25 | |
26 | SPI0DR = 0x8800; |
27 | while(!SPI0SR_SPTEF); |
28 | *lo = SPI0DRL; |
29 | |
30 | break; |
31 | |
32 | case Y: |
33 | |
34 | SPI0DR = 0x8B00; |
35 | while(!SPI0SR_SPTEF); |
36 | *hi = SPI0DRL; |
37 | |
38 | SPI0DR = 0x8A00; |
39 | while(!SPI0SR_SPTEF); |
40 | *lo = SPI0DRL; |
41 | |
42 | break; |
43 | |
44 | case Z: |
45 | |
46 | SPI0DR = 0x8D00; |
47 | while(!SPI0SR_SPTEF); |
48 | *hi = SPI0DRL; |
49 | |
50 | SPI0DR = 0x8C00; |
51 | while(!SPI0SR_SPTEF); |
52 | *lo = SPI0DRL; |
53 | |
54 | break; |
55 | } |
56 | } |
57 | |
58 | /* parses 8 bit HI/LO pairs into x/y/z words */ |
59 | void parse_raw(int in[], long set[]) { |
60 | |
61 | set[0] = (in[0] << 8) + in[1]; |
62 | set[1] = (in[2] << 8) + in[3]; |
63 | set[2] = (in[4] << 8) + in[5]; |
64 | } |
65 | |
66 | void configure_lsm() { |
67 | |
68 | /* wait for SPI ready */ |
69 | while(!SPI0SR_SPTEF); |
70 | |
71 | /* fill transfer reg */ |
72 | SPI0DR = 0x2474; |
73 | |
74 | /* wait for transfer */ |
75 | while(!SPI0SR_SPTEF); |
76 | } |
77 | |
78 | void configure_spi() { |
79 | |
80 | /* reroute spi I/O */ |
81 | MODRR_MODRR4 = 1; |
82 | |
83 | /* configure SPI */ |
84 | SPI0CR1_SSOE = 1; /* enable slave select */ |
85 | SPI0CR1_MSTR = 1; /* enable master */ |
86 | SPI0CR1_CPOL = 0; /* clock polarity */ |
87 | SPI0CR1_SPE = 1; /* enable system */ |
88 | SPI0CR1_LSBFE = 1; /* set endian-ness */ |
89 | |
90 | SPI0CR2_XFRW = 1; /* set 16 bit width */ |
91 | SPI0CR2_MODFEN = 1; /* enable slave select */ |
92 | } |
93 | |
94 | void main(void) { |
95 | |
96 | /* SDA :: SPI in :: PM2 :: white |
97 | * SDO :: SPI out :: PM4 :: blue |
98 | * SCL :: clock :: PM5 :: yellow |
99 | * CS :: select :: PM3 :: green |
100 | */ |
101 | |
102 | /* positional vars & init */ |
103 | long coords[3] = { null16, null16, null16 }; |
104 | int coord8[6] = { null8, null8, null8, null8, null8, null8 }; |
105 | |
106 | /* configure SPI */ |
107 | configure_spi(); |
108 | |
109 | /* configure LSM */ |
110 | configure_lsm(); |
111 | |
112 | /* latch intrs. */ |
113 | EnableInterrupts; |
114 | |
115 | for(;;) { |
116 | |
117 | /* read x hi/lo */ |
118 | read_axis(X, &coord8[0], &coord8[1]); |
119 | |
120 | /* read y hi/lo */ |
121 | read_axis(Y, &coord8[2], &coord8[3]); |
122 | |
123 | /* read z hi/lo */ |
124 | read_axis(Z, &coord8[4], &coord8[5]);; |
125 | |
126 | /* parse raw bytes into x/y/z vars */ |
127 | parse_raw(coord8, coords); |
128 | } |
129 | } |
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130 | |