108 lines
2.5 KiB
Lua
108 lines
2.5 KiB
Lua
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-- ****************************************************************************
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--
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-- Compatability wrapper for mapping ESP8266's spi module API to ESP32
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--
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-- Usage:
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--
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-- spi = require("spi_compat")([pin_sclk], [pin_mosi], [pin_miso], [pin_cs])
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--
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-- pin_sclk: GPIO pin for SCLK, optional
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-- pin_mosi: GPIO pin for MOSI, optional
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-- pin_miso: GPIO pin for MISO, optional
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-- pin_cs: GPIO pin for CS, optional
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--
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-- ****************************************************************************
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local M = {}
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local _pin_sclk, _pin_mosi, _pin_miso, _pin_cs
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local _spi
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local _duplex
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local _device
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-- ****************************************************************************
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-- Implement esp8266 compatability API
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--
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function M.setup(id, mode, cpol, cpha, databits, clock_div, duplex_mode)
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if databits ~= 8 then
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error("only 8 bits per item supported")
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end
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local bus_master = _spi.master(_spi.HSPI, {sclk = _pin_sclk, mosi = _pin_mosi, miso = _pin_miso})
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local dev_config = {}
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dev_config.cs = _pin_cs
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dev_config.mode = cpol * 2 + cpha
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dev_config.freq = 80000000 / clock_div
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_device = bus_master:device(dev_config)
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_duplex = duplex_mode or M.HALFDUPLEX
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end
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function M.send(id, ...)
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local results = {}
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local wrote = 0
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for idx = 1, select("#", ...) do
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local arg = select(idx, ...)
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if type(arg) == "number" then
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table.insert(results, _device:transfer(string.char(arg)):byte(1))
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wrote = wrote + 1
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elseif type(arg) == "string" then
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table.insert(results, _device:transfer(arg))
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wrote = wrote + #arg
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elseif type(arg) == "table" then
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local rtab = {}
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for i, data in ipairs(arg) do
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table.insert(rtab, _device:transfer(string.char(data)):byte(1))
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wrote = wrote + 1
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end
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table.insert(results, rtab)
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else
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error("wrong argument type")
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end
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end
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if _duplex == M.FULLDUPLEX then
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return wrote, unpack(results)
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else
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return wrote
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end
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end
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function M.recv(id, size, default_data)
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local def = default_data or 0xff
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return _device:transfer(string.char(def):rep(size))
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end
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return function (pin_sclk, pin_mosi, pin_miso, pin_cs)
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-- cache built-in module
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_spi = spi
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-- invalidate built-in module
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spi = nil
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-- forward unchanged functions
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-- forward constant definitions
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M.MASTER = 0
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M.CPOL_LOW = 0
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M.CPOL_HIGH = 1
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M.CPHA_LOW = 0
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M.CPHA_HIGH = 1
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M.HALFDUPLEX = 0
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M.FULLDUPLEX = 1
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_pin_sclk = pin_sclk
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_pin_mosi = pin_mosi
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_pin_miso = pin_miso
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_pin_cs = pin_cs
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return M
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end
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