ColorPAL documentation

ManualsBrandsParallax ManualsInfrared & Light SensorsColorPAL Color and Light Sensor

' {$STAMP BS2}

' {$PBASIC 2.5}

sio PIN 15

baud VAR Word

pwidth VAR Word

i VAR Byte

PAUSE 100

baud = $ffff

FOR i = 0 TO 255

PULSIN sio, 0, pwidth

baud = baud MAX pwidth

baud = baud << 1 - 20 | 32768

+nn

Address Networked ColorPALs

While in Direct mode (and only then) a plus sign (+) followed by two hexadecimal digits will be accepted

as a “network” address. Multiple ColorPALs can be paralleled and addressed individually in Direct mode.

Each ColorPAL can be assigned an eight-bit unit number, which is saved at EEPROM location 3F and

loaded when the ColorPAL resets. When a non-zero network address is received in Direct mode via the +

command, it is ANDed with the ColorPAL’s unit number. If the result is zero, the ColorPAL will ignore

further direct commands until either a 00 address or one which, when ANDed to its unit number, yields a

non-zero value. The 00 address can thus be thought of as a broadcast address, to which all ColorPALs

will respond. A new, unprogrammed ColorPAL comes with a unit number of 00, which means it will

respond

only

to address 00.

To change a ColorPAL’s unit number, simply create a one-instruction program, with the instruction being

one that takes a number (i.e. p or t), and save it to EEPROM location 3E. That will place the number in

location 3F and will be effective

after the next and subsequent resets

. Here’s an example:

SEROUT sio, baud, ["= p03 #3E"]

This programs the ColorPAL to have unit number 03 (%00000011), which means it will respond to any

address with one or both of its least-significant bits set.

IMPORTANT: Network addressing works

only

in Direct mode. It cannot be used to select which of two

or more ColorPALs already running programs gets to output color data, for example. It

can

be used,

however, to select which of several units can begin code execution.

When a ColorPAL comes out of reset, any commands sent without prepending an address are assumed to

be broadcast and won’t be blocked. That way, it’s easy simply to ignore the networking feature if you

don’t want to use it.

Here’s some example code that speaks to two ColorPALs, one with address 01; the other, 02. Unit 01

will display the colors green, blue, and red in that sequence; unit 02, blue, green, and red. Both display

red because they are addressed using the broadcast address 00. Note that there are

no spaces

in the

sub-sequence, !+02=. This is because those three commands are all sent in Direct mode, which does

not permit spaces.