From: Keith Packard Date: Sun, 7 Sep 2014 03:39:37 +0000 (-0700) Subject: altos: Reduce deviation at 2400/9600 baud X-Git-Tag: 1.4.9.3~2^2~4 X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=commitdiff_plain;h=f395bcaa620490954d4a42de9b4870bc12bedc91 altos: Reduce deviation at 2400/9600 baud There's no reason to use 20.5kHz deviation at 2400 and 9600 baud, and if we get a better receiver, we'll want to use narrower deviation to have less bandwidth sucking noise into the radio. The new values are (nominally) 5.125kHz deviation for 9600 baud and 1.5kHz deviation for 2400 baud. Signed-off-by: Keith Packard --- diff --git a/src/cc1111/ao_radio.c b/src/cc1111/ao_radio.c index 8f519958..b9821a42 100644 --- a/src/cc1111/ao_radio.c +++ b/src/cc1111/ao_radio.c @@ -60,19 +60,19 @@ * * M = 1, E = 3, bw = 75kHz * - * 20.5 kHz deviation, 9.6kbps signal + * 5.125 kHz deviation, 9.6kbps signal * - * m = 41 / 9.6, which is < 5.5: + * m = 10.25 / 9.6, which is < 5.5: * - * bw = 2.6 * 20.5 + 0.55 * 9.6 = 58.58kHz + * bw = 2.6 * 5.125 + 0.55 * 9.6 = 18.6kHz * - * M = 2, E = 3, bw = 62.5kHz + * M = 2, E = 3, bw = 53.6kHz * - * 20.5kHz deviation, 2.4kbps signal + * 1.28125kHz deviation, 2.4kbps signal * - * m = 41 / 2.4, which is > 5.5: + * m = 2.565 / 2.4, which is < 5.5: * - * bw = 2.1 * 20.5 + 1.9 * 2.4 = 47.61kHz + * bw = 2.6 * 20.5 + 1.9 * 2.4 = 47.61kHz * * M = 3, E = 3, bw = 53.6kHz * @@ -84,7 +84,7 @@ */ #define CHANBW_M_384 1 -#define CHANBW_M_96 2 +#define CHANBW_M_96 3 #define CHANBW_M_24 3 #define CHANBW_E 3 @@ -115,11 +115,19 @@ * * F = 24e6/2**17 * (8 + DEVIATION_M) * 2**DEVIATION_E * - * So M is 6 and E is 3 + * For 20.5kHz deviation, M is 6 and E is 3 + * For 5.125kHz deviation, M is 6 and E is 1 + * For 1.28125kHz deviation, M is 0 and E is 0 */ -#define DEVIATION_M 6 -#define DEVIATION_E 3 +#define DEVIATION_M_384 6 +#define DEVIATION_E_384 3 + +#define DEVIATION_M_96 6 +#define DEVIATION_E_96 1 + +#define DEVIATION_M_24 0 +#define DEVIATION_E_24 0 /* * For our RDF beacon, set the symbol rate to 2kBaud (for a 1kHz tone), @@ -182,9 +190,6 @@ static __code uint8_t radio_setup[] = { RF_CHANNR_OFF, 0, - RF_DEVIATN_OFF, ((DEVIATION_E << RF_DEVIATN_DEVIATION_E_SHIFT) | - (DEVIATION_M << RF_DEVIATN_DEVIATION_M_SHIFT)), - /* SmartRF says set LODIV_BUF_CURRENT_TX to 0 * And, we're not using power ramping, so use PA_POWER 0 */ @@ -284,8 +289,10 @@ static __code uint8_t fixed_pkt_setup[] = { RF_MDMCFG1_NUM_PREAMBLE_4 | (2 << RF_MDMCFG1_CHANSPC_E_SHIFT)), - RF_DEVIATN_OFF, ((DEVIATION_E << RF_DEVIATN_DEVIATION_E_SHIFT) | - (DEVIATION_M << RF_DEVIATN_DEVIATION_M_SHIFT)), +#if !HAS_RADIO_RATE + RF_DEVIATN_OFF, ((DEVIATION_E_384 << RF_DEVIATN_DEVIATION_E_SHIFT) | + (DEVIATION_M_384 << RF_DEVIATN_DEVIATION_M_SHIFT)), +#endif /* max packet length -- now set inline */ RF_PKTCTRL1_OFF, ((1 << PKTCTRL1_PQT_SHIFT)| @@ -298,19 +305,34 @@ static __code uint8_t fixed_pkt_setup[] = { }; #if HAS_RADIO_RATE -static __code uint8_t packet_rate_setup[] = { +static __code struct { + uint8_t mdmcfg4; + uint8_t deviatn; +} packet_rate_setup[] = { /* 38400 */ - ((CHANBW_E << RF_MDMCFG4_CHANBW_E_SHIFT) | - (CHANBW_M_384 << RF_MDMCFG4_CHANBW_M_SHIFT) | - (DRATE_E_384 << RF_MDMCFG4_DRATE_E_SHIFT)), + { + ((CHANBW_E << RF_MDMCFG4_CHANBW_E_SHIFT) | + (CHANBW_M_384 << RF_MDMCFG4_CHANBW_M_SHIFT) | + (DRATE_E_384 << RF_MDMCFG4_DRATE_E_SHIFT)), + ((DEVIATION_E_384 << RF_DEVIATN_DEVIATION_E_SHIFT) | + (DEVIATION_M_384 << RF_DEVIATN_DEVIATION_M_SHIFT)), + }, /* 9600 */ - ((CHANBW_E << RF_MDMCFG4_CHANBW_E_SHIFT) | - (CHANBW_M_96 << RF_MDMCFG4_CHANBW_M_SHIFT) | - (DRATE_E_96 << RF_MDMCFG4_DRATE_E_SHIFT)), + { + ((CHANBW_E << RF_MDMCFG4_CHANBW_E_SHIFT) | + (CHANBW_M_96 << RF_MDMCFG4_CHANBW_M_SHIFT) | + (DRATE_E_96 << RF_MDMCFG4_DRATE_E_SHIFT)), + ((DEVIATION_E_96 << RF_DEVIATN_DEVIATION_E_SHIFT) | + (DEVIATION_M_96 << RF_DEVIATN_DEVIATION_M_SHIFT)), + }, /* 2400 */ - ((CHANBW_E << RF_MDMCFG4_CHANBW_E_SHIFT) | - (CHANBW_M_24 << RF_MDMCFG4_CHANBW_M_SHIFT) | - (DRATE_E_24 << RF_MDMCFG4_DRATE_E_SHIFT)), + { + ((CHANBW_E << RF_MDMCFG4_CHANBW_E_SHIFT) | + (CHANBW_M_24 << RF_MDMCFG4_CHANBW_M_SHIFT) | + (DRATE_E_24 << RF_MDMCFG4_DRATE_E_SHIFT)), + ((DEVIATION_E_24 << RF_DEVIATN_DEVIATION_E_SHIFT) | + (DEVIATION_M_24 << RF_DEVIATN_DEVIATION_M_SHIFT)), + }, }; #endif @@ -380,7 +402,8 @@ ao_radio_get(uint8_t len) RF_FREQ0 = (uint8_t) (ao_config.radio_setting); RF_PKTLEN = len; #if HAS_RADIO_RATE - RF_MDMCFG4 = packet_rate_setup[ao_config.radio_rate]; + RF_MDMCFG4 = packet_rate_setup[ao_config.radio_rate].mdmcfg4; + RF_DEVIATN = packet_rate_setup[ao_config.radio_rate].deviatn; #endif } diff --git a/src/drivers/ao_cc1120.c b/src/drivers/ao_cc1120.c index 1b907940..3ea8b704 100644 --- a/src/drivers/ao_cc1120.c +++ b/src/drivers/ao_cc1120.c @@ -290,15 +290,32 @@ ao_radio_idle(void) } /* - * Packet deviation is 20.5kHz + * Packet deviation * * fdev = fosc >> 24 * (256 + dev_m) << dev_e * + * Deviation for 38400 baud should be 20.5kHz: + * * 32e6Hz / (2 ** 24) * (256 + 80) * (2 ** 5) = 20508Hz + * + * Deviation for 9600 baud should be 5.125kHz: + * + * 32e6Hz / (2 ** 24) * (256 + 80) * (2 ** 3) = 5127Hz + * + * Deviation for 2400 baud should be 1.28125kHz, but cc1111 and + * cc115l can't do that, so we'll use 1.5kHz instead: + * + * 32e6Hz / (2 ** 24) * (256 + 137) * (2 ** 1) = 1499Hz */ -#define PACKET_DEV_E 5 -#define PACKET_DEV_M 80 +#define PACKET_DEV_M_384 80 +#define PACKET_DEV_E_384 5 + +#define PACKET_DEV_M_96 80 +#define PACKET_DEV_E_96 3 + +#define PACKET_DEV_M_24 137 +#define PACKET_DEV_E_24 1 /* * For our packet data @@ -307,41 +324,55 @@ ao_radio_idle(void) * Rdata = -------------------------------------- * fosc * 2 ** 39 * + * Given the bit period of the baseband, T, the bandwidth of the + * baseband signal is B = 1/(2T). The overall bandwidth of the + * modulated signal is then Channel bandwidth = 2Δf + 2B. + * + * 38400 -- 2 * 20500 + 38400 = 79.4 kHz + * 9600 -- 2 * 5.125 + 9600 = 19.9 kHz + * 2400 -- 2 * 1.5 + 2400 = 5.4 khz + * * Symbol rate 38400 Baud: * * DATARATE_M = 239914 * DATARATE_E = 9 - * CHANBW = 74.42 (round to 100) + * CHANBW = 79.4 (round to 100) * * Symbol rate 9600 Baud: * * DATARATE_M = 239914 * DATARATE_E = 7 - * CHANBW = 58.58 (round to 62.5) + * CHANBW = 19.9 (round to 20) * * Symbol rate 2400 Baud: * * DATARATE_M = 239914 * DATARATE_E = 5 - * CHANBW = 47.61 (round to 50) + * CHANBW = 5.0 (round to 8.0) */ #define PACKET_DRATE_M 239914 #define PACKET_DRATE_E_384 9 -#define PACKET_CHAN_BW_384 0x02 /* 200 / 2 = 100 */ + +/* 200 / 2 = 100 */ +#define PACKET_CHAN_BW_384 ((0 << CC1120_CHAN_BW_CHFILT_BYPASS) | \ + (CC1120_CHAN_BW_ADC_CIC_DECFACT_20 << CC1120_CHAN_BW_ADC_CIC_DECFACT) | \ + (2 << CC1120_CHAN_BW_BB_CIC_DECFACT)) #define PACKET_DRATE_E_96 7 -#define PACKET_CHAN_BW_96 0x42 /* 125 / 2 = 62.5 */ +/* 200 / 10 = 20 */ +#define PACKET_CHAN_BW_96 ((0 << CC1120_CHAN_BW_CHFILT_BYPASS) | \ + (CC1120_CHAN_BW_ADC_CIC_DECFACT_20 << CC1120_CHAN_BW_ADC_CIC_DECFACT) | \ + (10 << CC1120_CHAN_BW_BB_CIC_DECFACT)) #define PACKET_DRATE_E_24 5 -#define PACKET_CHAN_BW_24 0x04 /* 200 / 4 = 50 */ +/* 200 / 25 = 8 */ +#define PACKET_CHAN_BW_24 ((0 << CC1120_CHAN_BW_CHFILT_BYPASS) | \ + (CC1120_CHAN_BW_ADC_CIC_DECFACT_20 << CC1120_CHAN_BW_ADC_CIC_DECFACT) | \ + (25 << CC1120_CHAN_BW_BB_CIC_DECFACT)) static const uint16_t packet_setup[] = { - CC1120_DEVIATION_M, PACKET_DEV_M, - CC1120_MODCFG_DEV_E, ((CC1120_MODCFG_DEV_E_MODEM_MODE_NORMAL << CC1120_MODCFG_DEV_E_MODEM_MODE) | - (CC1120_MODCFG_DEV_E_MOD_FORMAT_2_GFSK << CC1120_MODCFG_DEV_E_MOD_FORMAT) | - (PACKET_DEV_E << CC1120_MODCFG_DEV_E_DEV_E)), CC1120_DRATE1, ((PACKET_DRATE_M >> 8) & 0xff), CC1120_DRATE0, ((PACKET_DRATE_M >> 0) & 0xff), CC1120_PKT_CFG2, ((CC1120_PKT_CFG2_CCA_MODE_ALWAYS_CLEAR << CC1120_PKT_CFG2_CCA_MODE) | @@ -361,6 +392,10 @@ static const uint16_t packet_setup[] = { }; static const uint16_t packet_setup_384[] = { + CC1120_DEVIATION_M, PACKET_DEV_M_384, + CC1120_MODCFG_DEV_E, ((CC1120_MODCFG_DEV_E_MODEM_MODE_NORMAL << CC1120_MODCFG_DEV_E_MODEM_MODE) | + (CC1120_MODCFG_DEV_E_MOD_FORMAT_2_GFSK << CC1120_MODCFG_DEV_E_MOD_FORMAT) | + (PACKET_DEV_E_384 << CC1120_MODCFG_DEV_E_DEV_E)), CC1120_DRATE2, ((PACKET_DRATE_E_384 << CC1120_DRATE2_DATARATE_E) | (((PACKET_DRATE_M >> 16) & CC1120_DRATE2_DATARATE_M_19_16_MASK) << CC1120_DRATE2_DATARATE_M_19_16)), CC1120_CHAN_BW, PACKET_CHAN_BW_384, @@ -368,6 +403,10 @@ static const uint16_t packet_setup_384[] = { }; static const uint16_t packet_setup_96[] = { + CC1120_DEVIATION_M, PACKET_DEV_M_96, + CC1120_MODCFG_DEV_E, ((CC1120_MODCFG_DEV_E_MODEM_MODE_NORMAL << CC1120_MODCFG_DEV_E_MODEM_MODE) | + (CC1120_MODCFG_DEV_E_MOD_FORMAT_2_GFSK << CC1120_MODCFG_DEV_E_MOD_FORMAT) | + (PACKET_DEV_E_96 << CC1120_MODCFG_DEV_E_DEV_E)), CC1120_DRATE2, ((PACKET_DRATE_E_96 << CC1120_DRATE2_DATARATE_E) | (((PACKET_DRATE_M >> 16) & CC1120_DRATE2_DATARATE_M_19_16_MASK) << CC1120_DRATE2_DATARATE_M_19_16)), CC1120_CHAN_BW, PACKET_CHAN_BW_96, @@ -375,6 +414,10 @@ static const uint16_t packet_setup_96[] = { }; static const uint16_t packet_setup_24[] = { + CC1120_DEVIATION_M, PACKET_DEV_M_24, + CC1120_MODCFG_DEV_E, ((CC1120_MODCFG_DEV_E_MODEM_MODE_NORMAL << CC1120_MODCFG_DEV_E_MODEM_MODE) | + (CC1120_MODCFG_DEV_E_MOD_FORMAT_2_GFSK << CC1120_MODCFG_DEV_E_MOD_FORMAT) | + (PACKET_DEV_E_24 << CC1120_MODCFG_DEV_E_DEV_E)), CC1120_DRATE2, ((PACKET_DRATE_E_24 << CC1120_DRATE2_DATARATE_E) | (((PACKET_DRATE_M >> 16) & CC1120_DRATE2_DATARATE_M_19_16_MASK) << CC1120_DRATE2_DATARATE_M_19_16)), CC1120_CHAN_BW, PACKET_CHAN_BW_24, diff --git a/src/drivers/ao_cc1120.h b/src/drivers/ao_cc1120.h index 5d24c49a..943f3449 100644 --- a/src/drivers/ao_cc1120.h +++ b/src/drivers/ao_cc1120.h @@ -189,6 +189,12 @@ #define CC1120_FREQ_IF_CFG 0x0f #define CC1120_IQIC 0x10 #define CC1120_CHAN_BW 0x11 +#define CC1120_CHAN_BW_CHFILT_BYPASS 7 +#define CC1120_CHAN_BW_ADC_CIC_DECFACT 6 +#define CC1120_CHAN_BW_ADC_CIC_DECFACT_20 0 +#define CC1120_CHAN_BW_ADC_CIC_DECFACT_32 1 +#define CC1120_CHAN_BW_BB_CIC_DECFACT 0 + #define CC1120_MDMCFG1 0x12 #define CC1120_MDMCFG1_CARRIER_SENSE_GATE 7 #define CC1120_MDMCFG1_FIFO_EN 6 diff --git a/src/drivers/ao_cc115l.c b/src/drivers/ao_cc115l.c index b5103f9b..cf61acfe 100644 --- a/src/drivers/ao_cc115l.c +++ b/src/drivers/ao_cc115l.c @@ -249,23 +249,41 @@ ao_radio_idle(void) } /* - * Packet deviation is 20.5kHz + * Packet deviation * * fdev = fosc >> 17 * (8 + dev_m) << dev_e * + * For 38400 baud, use 20.5kHz: + * * 26e6 / (2 ** 17) * (8 + 5) * (2 ** 3) = 20630Hz + * + * For 9600 baud, use 5.125kHz: + * + * 26e6 / (2 ** 17) * (8 + 5) * (2 ** 1) = 5157Hz + * + * For 2400 baud, use 1.5kHz: + * + * 26e6 / (2 ** 17) * (8 + 0) * (2 ** 0) = 1587Hz */ -#define PACKET_DEV_E 3 -#define PACKET_DEV_M 5 +#define PACKET_DEV_E_384 3 +#define PACKET_DEV_M_384 5 + +#define PACKET_DEV_E_96 1 +#define PACKET_DEV_M_96 5 + +#define PACKET_DEV_E_24 0 +#define PACKET_DEV_M_24 0 /* - * For our packet data, set the symbol rate to 38400 Baud + * For our packet data: * * (256 + DATARATE_M) * 2 ** DATARATE_E * Rdata = -------------------------------------- * fosc * 2 ** 28 * + * For 38400 baud: + * * (256 + 131) * (2 ** 10) / (2**28) * 26e6 = 38383 * * DATARATE_M = 131 @@ -279,20 +297,33 @@ ao_radio_idle(void) #define PACKET_DRATE_E_96 8 #define PACKET_DRATE_E_24 6 -static const uint16_t packet_rate_setup[] = { - [AO_RADIO_RATE_38400] = ((0xf << 4) | - (PACKET_DRATE_E_384 << CC115L_MDMCFG4_DRATE_E)), - - [AO_RADIO_RATE_9600] = ((0xf << 4) | - (PACKET_DRATE_E_96 << CC115L_MDMCFG4_DRATE_E)), - - [AO_RADIO_RATE_2400] = ((0xf << 4) | - (PACKET_DRATE_E_24 << CC115L_MDMCFG4_DRATE_E)), +static const struct { + uint8_t mdmcfg4; + uint8_t deviatn; +} packet_rate_setup[] = { + [AO_RADIO_RATE_38400] = { + .mdmcfg4 = ((0xf << 4) | + (PACKET_DRATE_E_384 << CC115L_MDMCFG4_DRATE_E)), + .deviatn = ((PACKET_DEV_E_384 << CC115L_DEVIATN_DEVIATION_E) | + (PACKET_DEV_M_384 << CC115L_DEVIATN_DEVIATION_M)), + }, + + [AO_RADIO_RATE_9600] = { + .mdmcfg4 = ((0xf << 4) | + (PACKET_DRATE_E_96 << CC115L_MDMCFG4_DRATE_E)), + .deviatn = ((PACKET_DEV_E_96 << CC115L_DEVIATN_DEVIATION_E) | + (PACKET_DEV_M_96 << CC115L_DEVIATN_DEVIATION_M)), + }, + + [AO_RADIO_RATE_2400] = { + .mdmcfg4 = ((0xf << 4) | + (PACKET_DRATE_E_24 << CC115L_MDMCFG4_DRATE_E)), + .deviatn = ((PACKET_DEV_E_24 << CC115L_DEVIATN_DEVIATION_E) | + (PACKET_DEV_M_24 << CC115L_DEVIATN_DEVIATION_M)), + }, }; static const uint16_t packet_setup[] = { - CC115L_DEVIATN, ((PACKET_DEV_E << CC115L_DEVIATN_DEVIATION_E) | - (PACKET_DEV_M << CC115L_DEVIATN_DEVIATION_M)), CC115L_MDMCFG3, (PACKET_DRATE_M), CC115L_MDMCFG2, (0x00 | (CC115L_MDMCFG2_MOD_FORMAT_GFSK << CC115L_MDMCFG2_MOD_FORMAT) | @@ -418,7 +449,8 @@ ao_radio_set_mode(uint16_t new_mode) changes = new_mode & (~ao_radio_mode); if (changes & AO_RADIO_MODE_BITS_PACKET_TX) { - ao_radio_reg_write(CC115L_MDMCFG4, packet_rate_setup[ao_config.radio_rate]); + ao_radio_reg_write(CC115L_MDMCFG4, packet_rate_setup[ao_config.radio_rate].mdmcfg4); + ao_radio_reg_write(CC115L_DEVIATN, packet_rate_setup[ao_config.radio_rate].deviatn); for (i = 0; i < sizeof (packet_setup) / sizeof (packet_setup[0]); i += 2) ao_radio_reg_write(packet_setup[i], packet_setup[i+1]);