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vsergeev / lua-periphery

A Lua library for peripheral I/O (GPIO, LED, PWM, SPI, I2C, MMIO, Serial) in Linux.
MIT License
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Multiple GPIO reads fail #10

Closed gw0 closed 7 years ago

gw0 commented 8 years ago

As I understand GPIO ports, once opened, should be able to be read from or written to multiple times. But for reading only the first read works.

# lua
Lua 5.1.5  Copyright (C) 1994-2012 Lua.org, PUC-Rio (double int32)
> GPIO = require("periphery").GPIO
> gpio = GPIO(22, "in")
> print(gpio:read())
false
> print(gpio:read())
(error object is not a string)
>
vsergeev commented 8 years ago

Hello gw0,

Sorry about just getting to this now, it appears I missed it in my feed.

That's correct, and the loopback test (https://github.com/vsergeev/lua-periphery/blob/master/tests/test_gpio.lua#L98) does do multiple reads in succession. This leads me to believe it might be related to your environment and how the GPIOs are being rewound.

Could you paste the output of print(tostring(gpio:read())) on the second attempt? The tostring() will format the error object on Lua 5.1. Also, could you print the version of lua-periphery, with =require("periphery")._VERSION?

gw0 commented 8 years ago

Sorry, but I don't have access to the OpenWRT device with Lua where this was running.

Versions of lua-periphery and c-periphery were the ones you got by cloning it ~20 days ago and manually cross-compiling to mipsel architecture (see https://github.com/vsergeev/lua-periphery/pull/9).

vsergeev commented 7 years ago

I'm going to close this issue for now -- feel free to re-open if you (or someone else) encounters this problem again, and we can investigate further.