D01-501106-01 Rev B
DSVGA Design Reference Board Manual
11
6. ADVANCED USER INFORMATION
Microcontroller
The DSVGA Design Reference Board utilizes a Microchip PIC18F2523
microcontroller. This is a CMOS Flash microcontroller in a 28 pin package.
Provisions are on the circuit board for in circuit reprogramming. Please refer to
the Microchip PIC18F2523 datasheet available from Microchip Technology Inc.
for additional information about the microcontroller and programming.
The main function of the microcontroller is to communicate with the OLED
display. All communication is over the internal I
2
C bus and the microcontroller
acts as the bus master. On power up the registers of the OLED is initialized with
the default settings programmed into the microcontroller. After initialization the
microcontroller scans for user input and monitors the OLED.
I
2
C bus
The microcontroller is the bus master and communication occurs at the standard
100 KHz clock rate. The maximum speed allowed for I
2
C bus communication is
400 KHz. Please refer to the Philips I
2
C bus specification available on the Philips
website for detailed information.
Voltages
The power supply section of the DSVGA Design Reference Board consists of
several voltage regulators, some of which are adjustable with potentiometers.
Table 6-1 below describes the voltages and their purpose.
Voltage
Range
Typical
Purpose
Vinput
(USB)
+5.0 Volts
+5Volts
Main Supply
V5
5Volts ±10% (fixed)
5 Volts
LEDS, DAC
V3.3
3.3Volts ±10% (fixed)
3.3 Volts
DVI, RS232
V2.5
2.5Volts ±10% (fixed)
2.5 Volts
VAN
5.0V
5.0 Volts
OLED Anode
VPG
-1.8V
-1.8V
OLED Bias
VDD
1.8V ±10% (fixed)
1.8V
OLED
Table 6-1 shows the board’s various power supplies and their purposes
Bias Control
