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X5的相机同步方案

news 2025/11/7 9:27:42

1、sensor外部触发曝光

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2、lpwm软件触发

软件触发： trigger_mode = 0 ，代表内部软件触发，配置软件触发后， LPWM 驱动将自动提供基于 hrtimer 的周期为 1s 软件 trigger。本质就是 1s 去写一个 LPWM 寄存器 (LPWM_SW_TRIG)，让 LPWM 重新按照配置输出方波。
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lpwm属性配置

.lpwm_attr = {.enable = 1,.lpwm_chn_attr = {{	.trigger_source = 0,.trigger_mode = 0,.period = 33333,.offset = 10,.duty_time = 100,.threshold = 0,.adjust_step = 0,},{	.trigger_source = 0,.trigger_mode = 0,.period = 33333,.offset = 10,.duty_time = 100,.threshold = 0,.adjust_step = 0,},{	.trigger_source = 0,.trigger_mode = 0,.period = 33333,.offset = 10,.duty_time = 100,.threshold = 0,.adjust_step = 0,},{	.trigger_source = 0,.trigger_mode = 0,.period = 33333,.offset = 10,.duty_time = 100,.threshold = 0,.adjust_step = 0,},},},

3、lpwm硬件触发

硬件触发： trigger_mode = 1 ，代表代表外部触发，需要外接一个 PPS (pulse per second) 信号， LPWM 收到 PPS 信号后，硬件会按照软件的配置，输出方波。每收到一个 PPS 信号， LPWM 都会按照配置，重新出波。
检测 pps 信号这里有两种硬件方案，一种是 GPIO 中断，一种配置引脚 Time_Sync 功能

3.1 Time_Sync方案

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PWM模拟pps信号，周期为1s
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&pwm2 {status = "okay";pinctrl-names = "default";pinctrl-0 = <&pinctrl_pwm2_0 &pinctrl_pwm2_1>;
};

cd /sys/class/pwm/pwmchip0
echo 1 > export
cd pwm1/
echo 1000000000 > period #1s
echo 500000000 > duty_cycle #50%
echo 1 > enable

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复用TIME_SYNC1 引脚，作为pps信号输入脚

&lsio_iomuxc {gps_pps_func: gps_pps_func {horizon,pins = <LSIO_I2C1_SCL        LSIO_PINMUX_2        BIT_OFFSET20        MUX_ALT2        &pconf_input_en_3v3>; };
};

&hobot_pps {pinctrl-names = "default";pinctrl-0 = <&gps_pps_func>;status = "okay";
};

lpwm属性配置
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lpwm输出30HZ，触发sensor输出30帧图像

.lpwm_attr = {.enable = 1,.lpwm_chn_attr = {{	.trigger_source = 7,.trigger_mode = 1,.period = 33333,.offset = 10,.duty_time = 100,.threshold = 0,.adjust_step = 0,},{	.trigger_source = 7,.trigger_mode = 1,.period = 33333,.offset = 10,.duty_time = 100,.threshold = 0,.adjust_step = 0,},{	.trigger_source = 7,.trigger_mode = 1,.period = 33333,.offset = 10,.duty_time = 100,.threshold = 0,.adjust_step = 0,},{	.trigger_source = 7,.trigger_mode = 1,.period = 33333,.offset = 10,.duty_time = 100,.threshold = 0,.adjust_step = 0,},},