After
setting up Eclipse M2M toolchain for Raspberry Pi, I wanted to try out a simple lua script to blink LEDs using GPIOs. Here is the schematic and lua script for the same. I used the 3.3V available on RPi for powering the LEDs. 1 kiloohm resistors were used to limit the current passing through the LED. The cathodes of the LED were connected to drain the current into the GPIO pins. I used 4 LEDs connected to 4 different GPIOS (GPIO 22, GPIO 23, GPIO 24, GPIO 25).
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| Schematic |
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| Photo of the setup, I used a LED/Switches widget |
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| package.path = '/opt/mihini/lua/?.lua;/opt/mihini/lua/?/init.lua;' .. package.path
package.cpath = '/opt/mihini/lua/?.so;' .. package.cpath
local gpio = require"gpio"
local clock = os.clock
local function sleep(n) -- seconds
local t0 = clock()
while clock() - t0 <= n do end
end
local function toggle_pin(n)
local stat = gpio.read(n)
if stat == 1 then
gpio.write(n,0)
elseif stat == 0 then
gpio.write(n,1)
end
end
local function main()
gpio.configure(22, {direction="out", edge="both", activelow="0"})
gpio.configure(23, {direction="out", edge="both", activelow="0"})
gpio.configure(24, {direction="out", edge="both", activelow="0"})
gpio.configure(25, {direction="out", edge="both", activelow="0"})
gpio.write(22, 1)
gpio.write(23, 1)
gpio.write(24, 1)
gpio.write(25, 1)
while true do
sleep(1)
toggle_pin(22)
toggle_pin(23)
toggle_pin(24)
toggle_pin(25)
end
end
main()
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Lua script code to blink 4 LEDs
References:
- Raspberry Pi pinout
- Reference for the gpio module supplied with mihini
- Mihini Specifications
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