Project:USB Disco Dance Floor/v1/firmware: Difference between revisions
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The firmware will be responsible for listening for serial commands, and then acting upon them. This will primarily involve changing the display. | The firmware will be responsible for listening for serial commands, and then acting upon them. This will primarily involve changing the display. | ||
== Data types == | |||
=== Colour spec === | |||
The board reports the number of colours it supports at reset time. The colour(s) in a one-colour board will be referred to as '''R''', in a three-colour board as '''RGB''', and in a four-colour board as '''RGBU'''. This is because of the suggested LED choices of Red, Green, Blue, and Ultraviolet. The board also reports the number of bits (''n'') that it can use for setting the brightness of each colour LED. | |||
A colour spec consists of ''n'' bits of '''R''', followed by ''n'' bits of '''G''', '''B''', and '''U''' (as appropriate). If the total number of bits is not a multiple of 8, it will be right-padded with zeroes. | |||
Examples: | |||
* 4 bpc (bits per channel) and 4 colours would lead to a bit pattern of: <tt>RRRRGGGG BBBBUUUU</tt>. | |||
* 4 bpc and 3 colours would have a bit pattern of: <tt>RRRRGGGG BBBB0000</tt> | |||
* 12bps and 3 colours would have a bit pattern of: <tt>RRRRRRRR RRRRGGGG GGGGGGGG BBBBBBBB BBBB0000</tt> | |||
* 3bps and 3 colours would have a bit pattern of: <tt>RRRGGGBB B0000000</tt> | |||
=== Co-ordinate === | |||
A co-ordinate consists of four two-bit values packed into a single byte, with the bit pattern: <tt>xxyywwhh</tt>. Co-ordinates of (0,0) are at the top-left of the module, and increase downwards and rightwards. Note that the <tt>ww</tt> and <tt>hh</tt> bits may be ignored. | |||
=== Scroll spec === | |||
A scroll spec consists of two two-bit values and two one-bit values packed into a single byte, with the bit pattern: <tt>xxyy0w0h</tt>. The number of pixels to scroll along the X and Y axes is specified by <tt>xx</tt> and <tt>yy</tt>, and the direction is negative along the X/Y axis if <tt>w</tt> or <tt>h</tt> are set, respectively. | |||
== Commands == | == Commands == | ||
Revision as of 17:42, 4 April 2011
| USB Disco Dance Floor v1 Firmware | |
|---|---|
| Created | 2011-03-31 |
| Members | DMI |
| Project Status | Prototyping |
Introduction
The firmware will be responsible for listening for serial commands, and then acting upon them. This will primarily involve changing the display.
Data types
Colour spec
The board reports the number of colours it supports at reset time. The colour(s) in a one-colour board will be referred to as R, in a three-colour board as RGB, and in a four-colour board as RGBU. This is because of the suggested LED choices of Red, Green, Blue, and Ultraviolet. The board also reports the number of bits (n) that it can use for setting the brightness of each colour LED.
A colour spec consists of n bits of R, followed by n bits of G, B, and U (as appropriate). If the total number of bits is not a multiple of 8, it will be right-padded with zeroes.
Examples:
- 4 bpc (bits per channel) and 4 colours would lead to a bit pattern of: RRRRGGGG BBBBUUUU.
- 4 bpc and 3 colours would have a bit pattern of: RRRRGGGG BBBB0000
- 12bps and 3 colours would have a bit pattern of: RRRRRRRR RRRRGGGG GGGGGGGG BBBBBBBB BBBB0000
- 3bps and 3 colours would have a bit pattern of: RRRGGGBB B0000000
Co-ordinate
A co-ordinate consists of four two-bit values packed into a single byte, with the bit pattern: xxyywwhh. Co-ordinates of (0,0) are at the top-left of the module, and increase downwards and rightwards. Note that the ww and hh bits may be ignored.
Scroll spec
A scroll spec consists of two two-bit values and two one-bit values packed into a single byte, with the bit pattern: xxyy0w0h. The number of pixels to scroll along the X and Y axes is specified by xx and yy, and the direction is negative along the X/Y axis if w or h are set, respectively.
Commands
Commands start with a one-byte identifier, followed by zero or more data bytes. The number of data bytes is command-specific. The device should not output any data unless specified below.
| Command | Action | Min version |
|---|---|---|
| Status/Diagnostic Commands | ||
| 00 | Reset | 1.0 |
| Resets the board to an initial state, with all pixels off. The board sends four bytes representing its hardware and firmware versions (2 bytes each), followed by 2 bytes for hardware details. This command also resets the board ID to 0xFFFF (i.e. unset).
The high nybble of the first hardware info byte is the number of different colours supported (0x1, 0x3, or 0x4) and the low nybble is whether sensors are supported (0x1 for yes). The high nybble of the second byete specifies the number of bits needed to specify LED brightness. If this is different for different colours, the firmware will handle scaling. The low nybble does the same for sensor resolution. Note that, for the time being, resolutions should be a power of 2 (0x1, 0x2, 0x4, 0x8). | ||
| 01 | Identify | 1.0 |
| Informs the board of its two-byte board ID for this session. Note that board IDs 0x0000 and 0xFFFF are reserved. The board will respond with 0x00 (success). | ||
| 02 | Ping | 1.0 |
| Checks connectivity with the board. The board will respond with 0x00 (success) | ||
