src/main/drivers/vtx_rtc6705.c

   1 /*
   2  * This file is part of Cleanflight and Betaflight.
   3  *
   4  * Cleanflight and Betaflight are free software. You can redistribute
   5  * this software and/or modify this software under the terms of the
   6  * GNU General Public License as published by the Free Software
   7  * Foundation, either version 3 of the License, or (at your option)
   8  * any later version.
   9  *
  10  * Cleanflight and Betaflight are distributed in the hope that they
  11  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  12  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  13  * See the GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this software.
  17  *
  18  * If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 /*
  22  * Author: Giles Burgess (giles@multiflite.co.uk)
  23  *
  24  * This source code is provided as is and can be used/modified so long
  25  * as this header is maintained with the file at all times.
  26  */
  27
  28 #include <stdbool.h>
  29 #include <stdint.h>
  30
  31 #include "platform.h"
  32
  33 #if defined(USE_VTX_RTC6705) && !defined(USE_VTX_RTC6705_SOFTSPI)
  34
  35 #include "common/maths.h"
  36
  37 #include "drivers/bus_spi.h"
  38 #include "drivers/bus_spi_impl.h"
  39 #include "drivers/io.h"
  40 #include "drivers/time.h"
  41 #include "drivers/vtx_rtc6705.h"
  42
  43 #define RTC6705_SET_HEAD 0x3210 //fosc=8mhz r=400
  44 #define RTC6705_SET_R  400     //Reference clock
  45 #define RTC6705_SET_FDIV 1024  //128*(fosc/1000000)
  46 #define RTC6705_SET_NDIV 16    //Remainder divider to get 'A' part of equation
  47 #define RTC6705_SET_WRITE 0x11 //10001b to write to register
  48 #define RTC6705_SET_DIVMULT 1000000 //Division value (to fit into a uint32_t) (Hz to MHz)
  49
  50 #ifdef RTC6705_POWER_PIN
  51 static IO_t vtxPowerPin     = IO_NONE;
  52 #endif
  53
  54 static busDevice_t busInstance;
  55 static busDevice_t *busdev;
  56
  57 #define DISABLE_RTC6705()   IOHi(busdev->busdev_u.spi.csnPin)
  58
  59 #ifdef USE_RTC6705_CLK_HACK
  60 static IO_t vtxCLKPin       = IO_NONE;
  61 // HACK for missing pull up on CLK line - drive the CLK high *before* enabling the CS pin.
  62 #define ENABLE_RTC6705()    {IOHi(vtxCLKPin); delayMicroseconds(5); IOLo(busdev->busdev_u.spi.csnPin); }
  63 #else
  64 #define ENABLE_RTC6705()    IOLo(busdev->busdev_u.spi.csnPin)
  65 #endif
  66
  67 #define DP_5G_MASK          0x7000 // b111000000000000
  68 #define PA5G_BS_MASK        0x0E00 // b000111000000000
  69 #define PA5G_PW_MASK        0x0180 // b000000110000000
  70 #define PD_Q5G_MASK         0x0040 // b000000001000000
  71 #define QI_5G_MASK          0x0038 // b000000000111000
  72 #define PA_BS_MASK          0x0007 // b000000000000111
  73
  74 #define PA_CONTROL_DEFAULT  0x4FBD
  75
  76 #define RTC6705_RW_CONTROL_BIT      (1 << 4)
  77 #define RTC6705_ADDRESS             (0x07)
  78
  79 #define ENABLE_VTX_POWER()          IOLo(vtxPowerPin)
  80 #define DISABLE_VTX_POWER()         IOHi(vtxPowerPin)
  81
  82 /**
  83  * Reverse a uint32_t (LSB to MSB)
  84  * This is easier for when generating the frequency to then
  85  * reverse the bits afterwards
  86  */
  87 static uint32_t reverse32(uint32_t in)
  88 {
  89     uint32_t out = 0;
  90
  91     for (uint8_t i = 0 ; i < 32 ; i++) {
  92         out |= ((in>>i) & 1)<<(31-i);
  93     }
  94
  95     return out;
  96 }
  97
  98 /**
  99  * Start chip if available
 100  */
 101 bool rtc6705IOInit(const vtxIOConfig_t *vtxIOConfig)
 102 {
 103     busdev = &busInstance;
 104
 105     busdev->busdev_u.spi.csnPin = IOGetByTag(vtxIOConfig->csTag);
 106
 107     bool rtc6705HaveRequiredResources =
 108         (busdev->busdev_u.spi.csnPin != IO_NONE);
 109
 110 #ifdef RTC6705_POWER_PIN
 111     vtxPowerPin = IOGetByTag(vtxIOConfig->powerTag);
 112
 113     rtc6705HaveRequiredResources = rtc6705HaveRequiredResources && vtxPowerPin;
 114 #endif
 115
 116 #ifdef USE_RTC6705_CLK_HACK
 117     SPIDevice device = SPI_CFG_TO_DEV(vtxIOConfig->spiDevice);
 118     spiDevice_t *spi = &(spiDevice[device]);
 119
 120     vtxCLKPin = IOGetByTag(spi->sck);
 121     // we assume the CLK pin will have been initialised by the SPI code.
 122
 123     rtc6705HaveRequiredResources = rtc6705HaveRequiredResources && vtxCLKPin;
 124 #endif
 125
 126     if (!rtc6705HaveRequiredResources) {
 127         return false;
 128     }
 129
 130 #ifdef RTC6705_POWER_PIN
 131     IOInit(vtxPowerPin, OWNER_VTX_POWER, 0);
 132
 133     DISABLE_VTX_POWER();
 134     IOConfigGPIO(vtxPowerPin, IOCFG_OUT_PP);
 135 #endif
 136
 137
 138     IOInit(busdev->busdev_u.spi.csnPin, OWNER_VTX_CS, 0);
 139
 140     DISABLE_RTC6705();
 141     // GPIO bit is enabled so here so the output is not pulled low when the GPIO is set in output mode.
 142     // Note: It's critical to ensure that incorrect signals are not sent to the VTX.
 143     IOConfigGPIO(busdev->busdev_u.spi.csnPin, IOCFG_OUT_PP);
 144
 145     busdev->bustype = BUSTYPE_SPI;
 146     spiBusSetInstance(busdev, spiInstanceByDevice(SPI_CFG_TO_DEV(vtxIOConfig->spiDevice)));
 147
 148     return true;
 149 }
 150
 151 /**
 152  * Transfer a 25bit packet to RTC6705
 153  * This will just send it as a 32bit packet LSB meaning
 154  * extra 0's get truncated on RTC6705 end
 155  */
 156 static void rtc6705Transfer(uint32_t command)
 157 {
 158     command = reverse32(command);
 159
 160     ENABLE_RTC6705();
 161
 162     spiTransferByte(busdev->busdev_u.spi.instance, (command >> 24) & 0xFF);
 163     spiTransferByte(busdev->busdev_u.spi.instance, (command >> 16) & 0xFF);
 164     spiTransferByte(busdev->busdev_u.spi.instance, (command >> 8) & 0xFF);
 165     spiTransferByte(busdev->busdev_u.spi.instance, (command >> 0) & 0xFF);
 166
 167     delayMicroseconds(2);
 168
 169     DISABLE_RTC6705();
 170
 171     delayMicroseconds(2);
 172 }
 173
 174  /**
 175  * Set a frequency in Mhz
 176  * Formula derived from datasheet
 177  */
 178 void rtc6705SetFrequency(uint16_t frequency)
 179 {
 180     frequency = constrain(frequency, VTX_RTC6705_FREQ_MIN, VTX_RTC6705_FREQ_MAX);
 181
 182     const uint32_t val_a = ((((uint64_t)frequency*(uint64_t)RTC6705_SET_DIVMULT*(uint64_t)RTC6705_SET_R)/(uint64_t)RTC6705_SET_DIVMULT) % RTC6705_SET_FDIV) / RTC6705_SET_NDIV; //Casts required to make sure correct math (large numbers)
 183     const uint32_t val_n = (((uint64_t)frequency*(uint64_t)RTC6705_SET_DIVMULT*(uint64_t)RTC6705_SET_R)/(uint64_t)RTC6705_SET_DIVMULT) / RTC6705_SET_FDIV; //Casts required to make sure correct math (large numbers)
 184
 185     uint32_t val_hex = RTC6705_SET_WRITE;
 186     val_hex |= (val_a << 5);
 187     val_hex |= (val_n << 12);
 188
 189     spiSetDivisor(busdev->busdev_u.spi.instance, SPI_CLOCK_SLOW);
 190
 191     rtc6705Transfer(RTC6705_SET_HEAD);
 192     delayMicroseconds(10);
 193     rtc6705Transfer(val_hex);
 194 }
 195
 196 void rtc6705SetRFPower(uint8_t rf_power)
 197 {
 198     rf_power = constrain(rf_power, VTX_RTC6705_MIN_POWER, VTX_RTC6705_POWER_COUNT - 1);
 199
 200     spiSetDivisor(busdev->busdev_u.spi.instance, SPI_CLOCK_SLOW);
 201
 202     uint32_t val_hex = RTC6705_RW_CONTROL_BIT; // write
 203     val_hex |= RTC6705_ADDRESS; // address
 204     const uint32_t data = rf_power > 1 ? PA_CONTROL_DEFAULT : (PA_CONTROL_DEFAULT | PD_Q5G_MASK) & (~(PA5G_PW_MASK | PA5G_BS_MASK));
 205     val_hex |= data << 5; // 4 address bits and 1 rw bit.
 206
 207     rtc6705Transfer(val_hex);
 208 }
 209
 210 void rtc6705Disable(void)
 211 {
 212 #ifdef RTC6705_POWER_PIN
 213     DISABLE_VTX_POWER();
 214 #endif
 215 }
 216
 217 void rtc6705Enable(void)
 218 {
 219 #ifdef RTC6705_POWER_PIN
 220     ENABLE_VTX_POWER();
 221 #endif
 222 }
 223
 224 #endif