diff options
Diffstat (limited to 'firmware')
-rw-r--r-- | firmware/target/arm/imx31/gigabeat-s/powermgmt-imx31.c | 86 |
1 files changed, 44 insertions, 42 deletions
diff --git a/firmware/target/arm/imx31/gigabeat-s/powermgmt-imx31.c b/firmware/target/arm/imx31/gigabeat-s/powermgmt-imx31.c index b4a6c61fbb..e563fede43 100644 --- a/firmware/target/arm/imx31/gigabeat-s/powermgmt-imx31.c +++ b/firmware/target/arm/imx31/gigabeat-s/powermgmt-imx31.c | |||
@@ -53,36 +53,6 @@ const unsigned short percent_to_volt_charge[11] = | |||
53 | 3480, 3550, 3590, 3610, 3630, 3650, 3700, 3760, 3800, 3910, 3990 | 53 | 3480, 3550, 3590, 3610, 3630, 3650, 3700, 3760, 3800, 3910, 3990 |
54 | }; | 54 | }; |
55 | 55 | ||
56 | /** | ||
57 | * Fixed-point natural log | ||
58 | * taken from http://www.quinapalus.com/efunc.html | ||
59 | * "The code assumes integers are at least 32 bits long. The (positive) | ||
60 | * argument and the result of the function are both expressed as fixed-point | ||
61 | * values with 16 fractional bits, although intermediates are kept with 28 | ||
62 | * bits of precision to avoid loss of accuracy during shifts." | ||
63 | */ | ||
64 | static long flog(int x) | ||
65 | { | ||
66 | long t,y; | ||
67 | |||
68 | y=0xa65af; | ||
69 | if(x<0x00008000) x<<=16, y-=0xb1721; | ||
70 | if(x<0x00800000) x<<= 8, y-=0x58b91; | ||
71 | if(x<0x08000000) x<<= 4, y-=0x2c5c8; | ||
72 | if(x<0x20000000) x<<= 2, y-=0x162e4; | ||
73 | if(x<0x40000000) x<<= 1, y-=0x0b172; | ||
74 | t=x+(x>>1); if((t&0x80000000)==0) x=t,y-=0x067cd; | ||
75 | t=x+(x>>2); if((t&0x80000000)==0) x=t,y-=0x03920; | ||
76 | t=x+(x>>3); if((t&0x80000000)==0) x=t,y-=0x01e27; | ||
77 | t=x+(x>>4); if((t&0x80000000)==0) x=t,y-=0x00f85; | ||
78 | t=x+(x>>5); if((t&0x80000000)==0) x=t,y-=0x007e1; | ||
79 | t=x+(x>>6); if((t&0x80000000)==0) x=t,y-=0x003f8; | ||
80 | t=x+(x>>7); if((t&0x80000000)==0) x=t,y-=0x001fe; | ||
81 | x=0x80000000-x; | ||
82 | y-=x>>15; | ||
83 | return y; | ||
84 | } | ||
85 | |||
86 | /* Returns battery voltage from ADC [millivolts] */ | 56 | /* Returns battery voltage from ADC [millivolts] */ |
87 | unsigned int battery_adc_voltage(void) | 57 | unsigned int battery_adc_voltage(void) |
88 | { | 58 | { |
@@ -134,30 +104,62 @@ unsigned int cccv_regulator_dissipation(void) | |||
134 | /* Returns battery temperature from ADC [deg-C] */ | 104 | /* Returns battery temperature from ADC [deg-C] */ |
135 | int battery_adc_temp(void) | 105 | int battery_adc_temp(void) |
136 | { | 106 | { |
137 | unsigned int value = adc_read(ADC_BATTERY_TEMP); | ||
138 | /* E[volts] = value * 2.3V / 1023 | 107 | /* E[volts] = value * 2.3V / 1023 |
139 | * R[ohms] = E/I = E[volts] / 0.00002[A] (Thermistor bias current source) | 108 | * R[ohms] = E/I = E[volts] / 0.00002[A] (Thermistor bias current source) |
140 | * | 109 | * |
141 | * Steinhart-Hart thermistor equation (sans "C*ln^2(R)" term because it | 110 | * Steinhart-Hart thermistor equation: |
142 | * has negligible effect): | ||
143 | * [A + B*ln(R) + D*ln^3(R)] = 1 / T[°K] | 111 | * [A + B*ln(R) + D*ln^3(R)] = 1 / T[°K] |
144 | * | 112 | * |
145 | * Coeffients that fit experimental data (one thermistor so far, one run): | 113 | * Coeffients that fit experimental data (one thermistor so far, one run): |
146 | * A = 0.0013002631685462800 | 114 | * A = 0.0013002631685462800 |
147 | * B = 0.0002000841932612330 | 115 | * B = 0.0002000841932612330 |
148 | * D = 0.0000000640446750919 | 116 | * D = 0.0000000640446750919 |
149 | * | ||
150 | * Fixed-point output matches the floating-point version for each ADC | ||
151 | * value. | ||
152 | */ | 117 | */ |
118 | static const unsigned short ntc_table[] = | ||
119 | { | ||
120 | #if 0 /* These have degree deltas > 1 (except the final two) so leave them | ||
121 | * out. 70 deg C upper limit is quite sufficient. */ | ||
122 | 0, /* INF */ 1, /* 171 */ 2, /* 145 */ 3, /* 130 */ | ||
123 | 4, /* 121 */ 5, /* 114 */ 6, /* 108 */ 7, /* 104 */ | ||
124 | 8, /* 100 */ 9, /* 96 */ 10, /* 93 */ 11, /* 91 */ | ||
125 | 12, /* 88 */ 13, /* 86 */ 14, /* 84 */ 15, /* 82 */ | ||
126 | 16, /* 81 */ 17, /* 79 */ 18, /* 78 */ 19, /* 76 */ | ||
127 | 20, /* 75 */ 21, /* 74 */ 22, /* 72 */ 23, /* 71 */ | ||
128 | #endif | ||
129 | 24, /* 70 */ 25, /* 69 */ 26, /* 68 */ 27, /* 67 */ | ||
130 | 28, /* 66 */ 30, /* 65 */ 31, /* 64 */ 32, /* 63 */ | ||
131 | 33, /* 62 */ 35, /* 61 */ 36, /* 60 */ 38, /* 59 */ | ||
132 | 39, /* 58 */ 41, /* 57 */ 43, /* 56 */ 45, /* 55 */ | ||
133 | 47, /* 54 */ 49, /* 53 */ 51, /* 52 */ 53, /* 51 */ | ||
134 | 56, /* 50 */ 58, /* 49 */ 61, /* 48 */ 63, /* 47 */ | ||
135 | 66, /* 46 */ 69, /* 45 */ 73, /* 44 */ 76, /* 43 */ | ||
136 | 80, /* 42 */ 83, /* 41 */ 87, /* 40 */ 92, /* 39 */ | ||
137 | 96, /* 38 */ 101, /* 37 */ 106, /* 36 */ 111, /* 35 */ | ||
138 | 116, /* 34 */ 122, /* 33 */ 128, /* 32 */ 135, /* 31 */ | ||
139 | 142, /* 30 */ 149, /* 29 */ 156, /* 28 */ 164, /* 27 */ | ||
140 | 173, /* 26 */ 182, /* 25 */ 192, /* 24 */ 202, /* 23 */ | ||
141 | 212, /* 22 */ 224, /* 21 */ 236, /* 20 */ 249, /* 19 */ | ||
142 | 262, /* 18 */ 277, /* 17 */ 292, /* 16 */ 308, /* 15 */ | ||
143 | 325, /* 14 */ 344, /* 13 */ 363, /* 12 */ 384, /* 11 */ | ||
144 | 406, /* 10 */ 429, /* 9 */ 454, /* 8 */ 480, /* 7 */ | ||
145 | 509, /* 6 */ 539, /* 5 */ 571, /* 4 */ 605, /* 3 */ | ||
146 | 641, /* 2 */ 680, /* 1 */ 722, /* 0 */ 766, /* -1 */ | ||
147 | 813, /* -2 */ 864, /* -3 */ 918, /* -4 */ 976, /* -5 */ | ||
148 | }; | ||
149 | |||
150 | unsigned int value = adc_read(ADC_BATTERY_TEMP); | ||
151 | |||
153 | if (value > 0) | 152 | if (value > 0) |
154 | { | 153 | { |
155 | int R = 2070000 * value; | 154 | unsigned i; |
156 | long long ln = flog(R) + 83196; | 155 | |
157 | long long t0 = 425890304133ll; | 156 | for (i = 1; i < ARRAYLEN(ntc_table); i++) |
158 | long long t1 = 1000000*ln; | 157 | { |
159 | long long t3 = ln*ln*ln / 13418057; | 158 | if (ntc_table[i] > value) |
160 | return ((32754211579494400ll / (t0 + t1 + t3)) - 27315) / 100; | 159 | break; |
160 | } | ||
161 | |||
162 | return 71 - i; | ||
161 | } | 163 | } |
162 | 164 | ||
163 | return INT_MIN; | 165 | return INT_MIN; |