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Implement software spi

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This commit is contained in:
BlackMark 2022-05-28 15:43:42 +02:00
parent bb78d2291d
commit 999cd0e0c9
3 changed files with 110 additions and 1 deletions
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16
config.hpp
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@ -35,7 +35,7 @@ enum class BitOrder {
template <ClockDiv freq = ClockDiv::DIV_128, Mode mode = Mode::MODE_0, Side side = Side::MASTER,
BitOrder bitOrder = BitOrder::MSB_FIRST, io::P ssPin = io::P::B2, bool pullup = false>
struct Config {
struct HardwareConfig {
static constexpr auto FREQ = freq;
static constexpr auto MODE = mode;
static constexpr auto SIDE = side;
@ -44,4 +44,18 @@ struct Config {
static constexpr auto PULLUP = pullup;
};
template <io::P sckPin, io::P misoPin, io::P mosiPin, io::P ssPin, uint32_t freq = 100'000, Mode mode = Mode::MODE_0,
BitOrder bitOrder = BitOrder::MSB_FIRST, uint8_t bits = 8, bool pullup = false>
struct SoftwareConfig {
static constexpr auto SCK_PIN = sckPin;
static constexpr auto MISO_PIN = misoPin;
static constexpr auto MOSI_PIN = mosiPin;
static constexpr auto SS_PIN = ssPin;
static constexpr auto FREQ = freq;
static constexpr auto MODE = mode;
static constexpr auto BIT_ORDER = bitOrder;
static constexpr auto BITS = bits;
static constexpr auto PULLUP = pullup;
};
} // namespace spi

94
software.hpp Normal file
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@ -0,0 +1,94 @@
#pragma once
#include "../clock.hpp"
#include <stdint.h>
#include "../io/io.hpp"
#include "../util/type.hpp"
#include "../util/util.hpp"
namespace spi {
template <typename Cfg>
class Software {
static constexpr double calcClockDelay()
{
constexpr auto staticClockCycles = 10;
constexpr auto maxFrequency = F_CPU / staticClockCycles;
static_assert(Cfg::FREQ <= maxFrequency, "SPI frequency not achievable using selected clock speed");
constexpr auto staticDelay = (1.0 * 1000 * 1000 / maxFrequency);
const auto delayUs = ((1.0 * 1000 * 1000 / Cfg::FREQ) - staticDelay) / 2;
return (delayUs > 0 ? delayUs : 0);
}
static_assert(Cfg::BITS >= 1 && Cfg::BITS <= 64, "Word size must be in range [1-64]");
// clang-format off
using word_t = util::conditional_t<Cfg::BITS <= 8, uint8_t,
util::conditional_t<Cfg::BITS <= 16, uint16_t,
util::conditional_t<Cfg::BITS <= 32, uint32_t,
uint64_t>>>;
// clang-format on
public:
static void init()
{
sm_sck = ((Cfg::MODE == Mode::MODE_0 || Cfg::MODE == Mode::MODE_1) ? false : true);
sm_ss = true;
sm_sck.dir(io::Dir::OUT);
sm_miso.dir(io::Dir::IN);
sm_miso.pullup(Cfg::PULLUP);
sm_mosi.dir(io::Dir::OUT);
sm_ss.dir(io::Dir::OUT);
}
static word_t transfer(const word_t data)
{
auto dataIn = word_t{};
util::for_constexpr(
[&](const auto idx) {
constexpr auto i = idx.value;
constexpr auto bitPos = (Cfg::BIT_ORDER == BitOrder::MSB_FIRST ? Cfg::BITS - i - 1 : i);
if constexpr (Cfg::MODE == Mode::MODE_0 || Cfg::MODE == Mode::MODE_2) {
sm_mosi = data >> bitPos & 1;
_delay_us(DELAY_US);
sm_sck.toggle();
const auto receivedBit = sm_miso.read();
dataIn |= word_t{receivedBit} << bitPos;
_delay_us(DELAY_US);
sm_sck.toggle();
} else {
sm_sck.toggle();
sm_mosi = data >> bitPos & 1;
_delay_us(DELAY_US);
sm_sck.toggle();
const auto receivedBit = sm_miso.read();
dataIn |= word_t{receivedBit} << bitPos;
_delay_us(DELAY_US);
}
},
util::make_index_sequence<Cfg::BITS>{});
return dataIn;
}
static void select(const bool selectState)
{
sm_ss = !selectState;
}
private:
static io::Pin<Cfg::SCK_PIN> sm_sck;
static io::Pin<Cfg::MISO_PIN> sm_miso;
static io::Pin<Cfg::MOSI_PIN> sm_mosi;
static io::Pin<Cfg::SS_PIN> sm_ss;
static constexpr auto DELAY_US = calcClockDelay();
};
} // namespace spi

1
spi.hpp
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@ -2,6 +2,7 @@
#include "config.hpp"
#include "hardware.hpp"
#include "software.hpp"
#include "../io/io.hpp"