SBUS output problem

Hardware Radios
1

When I use hal.rcin->read(…), it can read all signals from RCIN. But when I call hal.rcout->write(…) there is nothing out at SBUS.

I already disable all safety functions.

#define MAX_RCIN_CHANNELS 16
static uint16_t last_rcin_value[MAX_RCIN_CHANNELS];
static bool inited = false;

void Rover::update_rcin()
{
if (inited == false) {
for (uint8_t i = 0; i < 16; i++) {
hal.rcout->enable_ch(i);
}
inited = true;
}

uint8_t nchannels = hal.rcin->num_channels();
if (nchannels == 0) {
    gcs().send_text(MAV_SEVERITY_WARNING, "No channels detected");
    return;
}

if (nchannels > MAX_RCIN_CHANNELS) {
    nchannels = MAX_RCIN_CHANNELS;
}

bool changed[MAX_RCIN_CHANNELS];
for (uint8_t i = 0; i < nchannels; i++) {
    changed[i] = false;
}

for (uint8_t i = 0; i < nchannels; i++) {
    uint16_t v = hal.rcin->read(i);
    hal.rcout->write(i, v);
    if (last_rcin_value[i] != v) {
        changed[i] = true;
        last_rcin_value[i] = v;
    }
}

gcs().send_text(MAV_SEVERITY_INFO, "%04u %04u %04u %04u %04u %04u %04u %04u",
    (unsigned)last_rcin_value[0],
    (unsigned)last_rcin_value[1],
    (unsigned)last_rcin_value[2],
    (unsigned)last_rcin_value[3],
    (unsigned)last_rcin_value[4],
    (unsigned)last_rcin_value[5],
    (unsigned)last_rcin_value[6],
    (unsigned)last_rcin_value[7]);

}

board : pixhawk fmuv3
firmware : Rover4.0.0
param SERVOx_FUNCTION = Disable