6
IN-CIRCUIT SERIAL PROGRAMMING (ICSP) CONNECTOR
By way of the header connector (CON1), the PIC18F252 system controller can be connected for onboard
reprogramming. The ICSP connector utilizes RB6 and RB7 of the system controller for in-circuit serial
programming. This connector is compatible with Microchip Promate 2 programmer, which support ICSP
interface.
ADC INPUT LOW-PASS FILTER
Since the LEDs are controlled by pulse width modulation output from the HDJD-J822, the sensor output
will also be pulse width modulated. Each sensor channel needs to be averaged by passing the sensor
output voltage through a low pass filter. On the board, this low pass filter is realized through a RC low-
pass filter (R11/C5, R12/C7 and R13/C8).
Further explanation on the resistor and capacitor selection is documented in the application note, which
is included in the CD-ROM.
OSCILLATOR OPTIONS
There are two oscillator onboard the development kit. One is for the HDJD-J822 color management
controller and the other is for the PIC18F252 system controller. For HDJD-J822, an RC oscillator
(2.5 MHz approximately) is supplied. The recommended resistor is 68 k
W
(R2) for the nominal oscillator
frequency of 2.5 MHz and a PWM frequency of 610 Hz.
For PIC18F252 system controller, a crystal oscillator (10 MHz) is supplied. If user would like to operate
the onboard system controller at different frequency, this crystal oscillator (Y1) can be changed to other
value.
EXTERNAL INPUT-OUTPUT CONNECTOR
Most of the HDJD-J822 color management controller and HDJD-S831 color sensor pins are mappable on
the external input-output connector. These pins include:
• PWM output R/G/B
(PWM R/G/B)
• I
2
C SDA
(SDA)
• I
2
C SCL
(SCL)
• Error flag
(ERR-FLAG)
• Bright control
(BRIGHT)
• Color control
(COLOR)
• Clock selector
(CLK_SEL)
• I
2
C address A0
(A0)
• I
2
C address A1
(A1)
• Sleep trigger
(SLEEP)
• Clock reference
(CLKREF)
• External ADC voltage reference
(VREF)
• Color sensor input R/G/B
(BLUE/GREEN/RED)
• 5V/+5V supply pin
(5V/+5V)
• AGND/DGND ground pin
(AGND/DGND)
