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LP-585 Change the calc for channel generator and avoid rounding issues.

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Take in account the frequency deviation and keep Tx inside defined band.
This commit is contained in:
Laurent Lalanne 2018-03-08 21:47:23 +01:00
parent b8239e3cf8
commit dbb569278a
1 changed files with 26 additions and 7 deletions
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33
flight/pios/common/pios_rfm22b.c
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@ -349,6 +349,18 @@ static const uint8_t channel_spacing[] = {
4, /* 256kps */
};
static const uint8_t channel_limits[] = {
1, /* 9.6kbps */
1, /* 19.2kps */
1, /* 32kps */
1, /* 57.6kps */
1, /* 64kps */
1, /* 100kps */
2, /* 128kps */
2, /* 192kps */
2, /* 256kps */
};
static const uint8_t reg_1C[] = { 0x01, 0x05, 0x06, 0x95, 0x95, 0x81, 0x88, 0x8B, 0x8D }; // rfm22_if_filter_bandwidth
static const uint8_t reg_1D[] = { 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40 }; // rfm22_afc_loop_gearshift_override
@ -2671,7 +2683,9 @@ static bool rfm22_gen_channels(uint32_t coordid, enum rfm22b_datarate rate, uint
{
uint32_t data = 0;
uint8_t cpos = 0;
uint8_t chan_range = (max / channel_spacing[rate] - min / channel_spacing[rate]) + 1;
uint8_t chan_min_limit = min + channel_limits[rate];
uint8_t chan_max_limit = max - channel_limits[rate];
uint8_t chan_count = ((chan_max_limit - chan_min_limit) / channel_spacing[rate]) + 1;
uint8_t key[SHA1_DIGEST_LENGTH] = { 0 };
uint8_t digest[SHA1_DIGEST_LENGTH];
uint8_t *all_channels;
@ -2680,12 +2694,15 @@ static bool rfm22_gen_channels(uint32_t coordid, enum rfm22b_datarate rate, uint
memcpy(key, &coordid, sizeof(coordid));
for (int i = 0; i < chan_range; i++) {
all_channels[i] = min / channel_spacing[rate] + i;
for (int i = 0; i < chan_count; i++) {
all_channels[i] = chan_min_limit + (i * channel_spacing[rate]);
}
// DEBUG_PRINTF(3, "\r\nChannel Min: %d Max:%d - Spacing: %d Limits: %d\r\n", min, max, channel_spacing[rate], channel_limits[rate]);
// DEBUG_PRINTF(3, "Result: Channel count: %d - Usable channels from ch%d to ch%d\r\n", chan_count, all_channels[0], all_channels[chan_count - 1]);
int j = SHA1_DIGEST_LENGTH;
for (int i = 0; i < chan_range && i < MAX_CHANNELS; i++) {
for (int i = 0; i < chan_count && i < MAX_CHANNELS; i++) {
uint8_t rnd;
uint8_t r;
uint8_t tmp;
@ -2697,14 +2714,16 @@ static bool rfm22_gen_channels(uint32_t coordid, enum rfm22b_datarate rate, uint
}
rnd = digest[j];
j++;
r = rnd % (chan_range - i) + i;
r = rnd % (chan_count - i) + i;
tmp = all_channels[i];
all_channels[i] = all_channels[r];
all_channels[r] = tmp;
}
for (int i = 0; i < chan_range && cpos < MAX_CHANNELS; i++, cpos++) {
channels[cpos] = all_channels[i] * channel_spacing[rate];
// DEBUG_PRINTF(3, "Final channel list:");
for (int i = 0; i < chan_count && cpos < MAX_CHANNELS; i++, cpos++) {
channels[cpos] = all_channels[i];
// DEBUG_PRINTF(3, " %d ", all_channels[i]);
}
*clen = cpos & 0xfe;