Difference between revisions of "NEC IR Remote Control Interface with 8051"
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<b>Logical '0':</b> A 562.5µs pulse burst followed by a 562.5µs space, with a total transmit time of 1.125ms<br> | <b>Logical '0':</b> A 562.5µs pulse burst followed by a 562.5µs space, with a total transmit time of 1.125ms<br> | ||
<b>Logical '0':</b> A 562.5µs pulse burst followed by a 1.6875ms space, with a total transmit time of 2.25ms | <b>Logical '0':</b> A 562.5µs pulse burst followed by a 1.6875ms space, with a total transmit time of 2.25ms | ||
| + | |||
| + | When a key is pressed on the remote controller, the message transmitted consists of the following, in order: | ||
| + | #A 9ms leading pulse burst (16 times the pulse burst length used for a logical data bit) | ||
| + | a 4.5ms space | ||
| + | #The 8-bit address for the receiving device | ||
| + | #The 8-bit logical inverse of the address | ||
| + | #The 8-bit command | ||
| + | #The 8-bit logical inverse of the command | ||
| + | #A final 562.5µs pulse burst to signify the end of message transmission. | ||
| + | The four bytes of data bits are each sent least significant bit first. Figure 1 illustrates the format of an NEC IR transmission frame, for an address of 00h (00000000b) and a command of ADh (10101101b). | ||
| + | |||
| + | [[File:NecIrRemote 0.png]] | ||
=Downloads= | =Downloads= | ||
[[File:Schematic 8051 Interfacing Zigbee.JPG|680px]] | [[File:Schematic 8051 Interfacing Zigbee.JPG|680px]] | ||
<span style="color:red">'''Code and Explanation will be updated soon..'''</span> | <span style="color:red">'''Code and Explanation will be updated soon..'''</span> | ||
Revision as of 17:42, 29 July 2016
IR Remote Controllers and receivers follow standard protocols for sending and receiving the data. Some of the standard protocols are NEC , JVC , SIRC (Sony Infrared Remote Control) etc. We will be discussing only the NEC protocol. After understanding the frame format of IR Remote, We will be interfacing a IR receiver with 8051 and decode the key pressed.
NEC Protocol
NEC IR protocol encodes the keys using a 32bit frame format as shown below.
| NEC Frame Format | |||
| Address | Complement of Address | Command | Complement of Command |
| LSB-MSB(0-7) | LSB-MSB(8-15) | LSB-MSB(16-23) | LSB-MSB(24-31) |
Each bit is transmitted using the pulse distance as shown below.
Logical '0': A 562.5µs pulse burst followed by a 562.5µs space, with a total transmit time of 1.125ms
Logical '0': A 562.5µs pulse burst followed by a 1.6875ms space, with a total transmit time of 2.25ms
When a key is pressed on the remote controller, the message transmitted consists of the following, in order:
- A 9ms leading pulse burst (16 times the pulse burst length used for a logical data bit)
a 4.5ms space
- The 8-bit address for the receiving device
- The 8-bit logical inverse of the address
- The 8-bit command
- The 8-bit logical inverse of the command
- A final 562.5µs pulse burst to signify the end of message transmission.
The four bytes of data bits are each sent least significant bit first. Figure 1 illustrates the format of an NEC IR transmission frame, for an address of 00h (00000000b) and a command of ADh (10101101b).
Downloads
Code and Explanation will be updated soon..