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ruanhaishen
Nodemcu Firmware
Commits
71dd55ba
Commit
71dd55ba
authored
Jan 25, 2015
by
Javier Yáñez
Browse files
Turn some variables to local
ake some adjustments because of the optimization using local variables
parent
3ede2de2
Changes
1
Hide whitespace changes
Inline
Side-by-side
lua_modules/dht22/dht22.lua
View file @
71dd55ba
...
...
@@ -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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