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ruanhaishen
Nodemcu Firmware
Commits
08717918
Commit
08717918
authored
Jan 26, 2015
by
Vowstar
Browse files
Merge pull request #130 from javieryanez/patch-1
Turn some variables to local
parents
3ede2de2
71dd55ba
Changes
1
Hide whitespace changes
Inline
Side-by-side
lua_modules/dht22/dht22.lua
View file @
08717918
...
...
@@ -13,23 +13,22 @@ _G[moduleName] = M
local
humidity
local
temperature
local
checksum
local
checksumTest
function
M
.
read
(
pin
)
local
checksum
local
checksumTest
humidity
=
0
temperature
=
0
checksum
=
0
-- Use Markus Gritsch trick to speed up read/write on GPIO
gpio_read
=
gpio
.
read
gpio_write
=
gpio
.
write
local
gpio_read
=
gpio
.
read
bitStream
=
{}
local
bitStream
=
{}
for
j
=
1
,
40
,
1
do
bitStream
[
j
]
=
0
end
bitlength
=
0
local
bitlength
=
0
-- Step 1: send out start signal to DHT22
gpio
.
mode
(
pin
,
gpio
.
OUTPUT
)
...
...
@@ -43,13 +42,13 @@ function M.read(pin)
-- Step 2: DHT22 send response signal
-- bus will always let up eventually, don't bother with timeout
while
(
gpio_read
(
pin
)
==
0
)
do
end
c
=
0
while
(
gpio_read
(
pin
)
==
1
and
c
<
1
00
)
do
c
=
c
+
1
end
local
c
=
0
while
(
gpio_read
(
pin
)
==
1
and
c
<
5
00
)
do
c
=
c
+
1
end
-- bus will always let up eventually, don't bother with timeout
while
(
gpio_read
(
pin
)
==
0
)
do
end
c
=
0
while
(
gpio_read
(
pin
)
==
1
and
c
<
1
00
)
do
c
=
c
+
1
end
while
(
gpio_read
(
pin
)
==
1
and
c
<
5
00
)
do
c
=
c
+
1
end
-- Step 3: DHT22 send data
for
j
=
1
,
40
,
1
do
while
(
gpio_read
(
pin
)
==
1
and
bitlength
<
10
)
do
...
...
@@ -63,17 +62,17 @@ function M.read(pin)
--DHT data acquired, process.
for
i
=
1
,
16
,
1
do
if
(
bitStream
[
i
+
0
]
>
2
)
then
if
(
bitStream
[
i
]
>
4
)
then
humidity
=
humidity
+
2
^
(
16
-
i
)
end
end
for
i
=
1
,
16
,
1
do
if
(
bitStream
[
i
+
16
]
>
2
)
then
if
(
bitStream
[
i
+
16
]
>
4
)
then
temperature
=
temperature
+
2
^
(
16
-
i
)
end
end
for
i
=
1
,
8
,
1
do
if
(
bitStream
[
i
+
32
]
>
2
)
then
if
(
bitStream
[
i
+
32
]
>
4
)
then
checksum
=
checksum
+
2
^
(
8
-
i
)
end
end
...
...
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