diff --git a/hardware.hpp b/hardware.hpp index abbb756..f6d15e3 100644 --- a/hardware.hpp +++ b/hardware.hpp @@ -4,6 +4,7 @@ #include "../type/type.hpp" +#include #include #define FORCE_INLINE __attribute__((always_inline)) @@ -12,7 +13,6 @@ namespace uart { enum class Mode { ASYNCHRONOUS, - ASYNCHRONOUS_2X, SYNCHRONOUS_MASTER, SYNCHRONOUS_SLAVE, SPI, @@ -46,7 +46,12 @@ class Hardware { public: static void init() FORCE_INLINE { - constexpr auto BaudVal = calcBaud(); + constexpr auto AbsDoubleError = fabs(calcBaudError()); + constexpr auto AbsNormalError = fabs(calcBaudError()); + static_assert(AbsDoubleError <= 3.0 || AbsNormalError <= 3.0, "Baud rate error over 3%, probably unusable"); + + constexpr auto UseDoubleSpeed = (AbsDoubleError < AbsNormalError); + constexpr auto BaudVal = calcBaudVal(); *getRegPtr() = static_cast(BaudVal >> 8); *getRegPtr() = static_cast(BaudVal); @@ -58,10 +63,12 @@ class Hardware { constexpr auto EnableRx = calcRxState(); constexpr auto EnableTx = calcTxState(); constexpr auto InterruptVal = calcInterrupt(); + constexpr auto DoubleSpeedVal = calcDoubleSpeedVal(); constexpr uint8_t ControlRegB = DataBitsValues.regBVal | EnableRx | EnableTx | InterruptVal; constexpr uint8_t ControlRegC = DataBitsValues.regCVal | ParityVal | StopBitsVal | ModeVal; + *getRegPtr() |= DoubleSpeedVal; *getRegPtr() = ControlRegB; *getRegPtr() = ControlRegC; } @@ -134,13 +141,39 @@ class Hardware { uint8_t regBVal = 0; }; - static constexpr auto calcBaud() + template + static constexpr auto calcBaudVal() { - // The actual formula is (F_CPU / (16 * baudRate)) - 1, but this one has the advantage of rounding correctly - constexpr auto BaudVal = (F_CPU + 8 * cfg::BAUD_RATE) / (16 * cfg::BAUD_RATE) - 1; + if constexpr (DoubleSpeed) { + constexpr auto BaudVal = static_cast(round(F_CPU / (8.0 * cfg::BAUD_RATE) - 1)); + return BaudVal; + } + + constexpr auto BaudVal = static_cast(round(F_CPU / (16.0 * cfg::BAUD_RATE) - 1)); return BaudVal; } + template + static constexpr auto calcBaudRate() + { + if constexpr (DoubleSpeed) { + constexpr auto BaudRate = static_cast(round(F_CPU / (8.0 * (BaudVal + 1)))); + return BaudRate; + } + + constexpr auto BaudRate = static_cast(round(F_CPU / (16.0 * (BaudVal + 1)))); + return BaudRate; + } + + template + static constexpr auto calcBaudError() + { + constexpr auto BaudVal = calcBaudVal(); + constexpr auto ClosestBaudRate = calcBaudRate(); + constexpr auto BaudError = (static_cast(ClosestBaudRate) / cfg::BAUD_RATE - 1) * 100; + return BaudError; + } + static constexpr auto calcDataBits() { DataBitsVal dataBitsVal; @@ -233,6 +266,17 @@ class Hardware { return interruptVal; } + + template + static constexpr auto calcDoubleSpeedVal() + { + uint8_t doubleSpeedVal = 0; + + if constexpr (DoubleSpeed) + doubleSpeedVal = (1 << CtrlFlagsA::SPEED_2X); + + return doubleSpeedVal; + } }; template