The Digilent Pmod COLOR (Revision A) is a color sensor module with the ability to sense red, green, blue and clear light. The onboardAMS TCS3472integrates an IR blocking filter to accurately determine the color of objects as well as sense ambient light under varying lighting conditions and through attenuating materials.

• Red, green, blue, and clear light sensing
• IR-blocking filter
• WhiteLEDfor reflective measurements
• Suitable for use behind darkened glass
• Small PCB size for flexible designs 0.8“ × 1.25” (2.0 cm × 3.2 cm)
• 6-pin Pmod connector with I²C interface
• Pass-through Pmod host port for daisy chaining
• Follows DigilentPmod Interface Specification Type 6
• Library and example code available on theResource Center

¹ - Percent values are with respect to the counts measured by the clear (non-color filtered) channel

The pins on the pin header are spaced 100 mil apart. The PCB is 1.34 inches long on the sides parallel to the pins on the pin header and 0.8 inches long on the sides perpendicular to the pin header.

The Pmod Color utilizes the TCS3472 to detect color in the near vicinity. While communicating with the host board via theI²C protocolusing an I²C address of 0x29 users can measure color. A user controlled whiteLEDis also provided to help illuminate the object and improve color determination; theLEDis very bright so it is recommended that users do not stare at the light.

The Pmod COLOR communicates with the host board via theI²C protocol. By first sending the 7-bit I²C device address of 0101001 (0x29), users may receive the color data from the TCS3472. Each of the fourADCchannels (red, green, blue, and clear) sends it's conversion from theADCto the host buffer simultaneously.

The TCS3472 can set the gain and integration time for each round of data collection. Integration time provides more time for the color sensor to collect more data, providing accurate data and helping to prevent the data from disproportionately capturing any overexposure that may occur. Each set of the 16-bit data is organized in a low-byte, high-byte arrangement.

每一个刺ee colors (RGB) and the clear color byte has two registers to store the high and low data bytes for each measurement. The data registers are arranged in a low byte, high byte arrangement.

The Command register controls the functionality of the internal address pointer and clears interrupts.

¹ - This is the value on power-up and reset ² - See theTransaction Tablebelow ³ - See theAddress Field and Special Function Tablebelow

³ - See theAddress Field and Special Function Tablebelow

The Control Register (0x0F) sets the gain factor applied to theADCcolor data.

¹ - This is the value on power-up and reset ² - See theGain Value Tablebelow

The Status register (0x13) is a read-only register that provides the state of the channel interrupt and if the ADCs have completed a data collection.

¹ - This is the value on power-up and reset

Here is the series of commands to acquire a set of data from the Pmod COLOR via pseudo I²C code.

1. Power on the Pmod COLOR.
2. Provide a START condition and call the device ID with a write bit

   I2CBegin(0x52); //device ID 0x29 with a write (0) bit

3. Wait to receive an ACK from the Pmod COLOR.
4. Provide a command to maintain the pointer address OR'd with the Enable register (0x00)

   I2CWrite(0xA0); //Maintain the pointer address at the Enable register

5. Wait to receive an ACK from the Pmod COLOR.
6. Send the Enable Address and enable the oscillators.

   I2CWrite(0x01); //0x01 enables the oscillators for the timers and ADC channels

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8. Send the Enable Address and enable the ADCs for all 4 channels.

   I2CWrite(0x02); //0x02 enables the ADC channels

9. Wait to receive an ACK from the Pmod COLOR and then send a STOP condition.
10. Delay 2.4 ms for the ADCs preparing themselves for data measurement and at least 2.4 ms by default for the integration time during the data collection process.
11. Send a START condition and call the device ID with a write bit

    I2CBegin(0x52); //device ID 0x29 with a write (0) bit

12. Wait to receive an ACK from the Pmod COLOR.
13. Provide a command to auto-increment the address pointer OR'd with the first data register (0x14)

    I2CWrite(0xB4); //Auto-increment the pointer address starting at the Clear Data Low Byte register

14. Wait to receive an ACK from the Pmod COLOR
15. Provide a RESTART condition and call the device ID with a read bit

    I2CBegin(0x53); //device ID 0x29 with a read (1) bit

16. Wait to receive an ACK from the Pmod COLOR.
17. Collect all 8 data bytes corresponding to the low and high data byte registers of the clear, red, green, and blue data, respectively, sending an ACK to the Pmod Color between each byte.

    I2CReadMultiple(8); //read in the 8 data registers taking advantage of the auto-incrementing pointer

18. Send a STOP condition.

The Pmod COLOR is ideal for fun applications that perform different tasks based on the color of an object. This is perfect for sorting different objects or controlling a motor based on the detected color temperature.

The AMS TCS3472 module has four differentADCchannels to detect red, green, blue, and clear ambient light data. Colorimeters of this nature do not have perfect sensing capability so some of the color sensors, notably green and blue, do not measure the full data range of the data

An example timing diagram for reading and writing to the Pmod COLOR taken from the AMS datasheet is provided below:

When using an external power supply to run the Pmod, be sure to stay within the parameters provided inSpecifications.

The schematics of the Pmod COLOR are availablehere. Additional information about the color sensor including communication modes and specific timings of the chip can be found by downloading its datasheet from the AMS website herehere.

Example code demonstrating how to get information from the Pmod COLOR can be found on its Resource Centerhere.

If you have any questions or comments about the Pmod COLOR, feel free to post them under the appropriate section (“Add-on Boards”) of theDigilent Forum.