VGA connectors pinouts
There are at least four versions of the VGA connector, which are the three-row 15 pin DE-15 (also called mini sub D15) in original and DDC2 pinouts, a less featureful and far less common 9-pin VGA, and a Mini-VGA used for laptops. The image and below table are the newer 15-pin VGA VESA DDC2 connector pinout.
VGA DDC2 connector pinout:
| Pin | Name | Dir | Description |
|---|---|---|---|
| 1 | RED |  |
Red Video (75 ohm, 0.7 V p-p) |
| 2 | GREEN | |
Green Video (75 ohm, 0.7 V p-p) |
| 3 | BLUE | |
Blue Video (75 ohm, 0.7 V p-p) |
| 4 | RES | RESERVED | |
| 5 | SGND |  |
Ground |
| 6 | RGND | |
Red Ground |
| 7 | GGND | |
Green Ground |
| 8 | BGND | |
Blue Ground |
| 9 | KEY | - | Key (No pin) / Optional +5V output from graphics card |
| 10 | GND | |
Sync Ground |
| 11 | ID0 |  |
Monitor ID Bit 0 (optional) |
| 12 | SDA |  |
I2C bidirectional data line |
| 13 | HSYNC or CSYNC | |
Horizontal Sync (or Composite Sync) |
| 14 | VSYNC | |
Vertical Sync which works also as data clock |
| 15 | SCL | |
I2C data clock in DDC2, Monitor ID3 in DDC1. A slave can pull SCL low to make the master wait. |
Note: Direction is Computer relative Monitor. All VGA pinout signals except R, G, B are TTL level signals.
The basic VGA display modes of 80x25 character mode and 640x480 in graphics mode are still supported by all modern graphic cards, independent of the extended modes supported by these cards.
VGA video specifications are:
- 256 KB Video RAM .
- 16-color and 256-color modes
- 262,144-value color palette (six bits each for red, green, and blue)
- Selectable 25.175 MHz or 28.322 MHz master clock
- Maximum of 800 horizontal pixels
- Maximum of 600 lines (Interlaced)
- Refresh rates at up to 70 Hz
- Vertical blank interrupt
- Planar mode: up to 16 colors (4 bit planes)
- Packed-pixel mode: 256 colors (Mode 13h)
- Hardware smooth scrolling support
- Some Raster Ops support
- Barrel shifter
- Split screen support
- 0.7 V peak-to-peak
- 75 ohm double-terminated impedance (18.7 mA – 13 mW)
VGA VESA DDC
VESA Display Data Channel is a method for integrating digital interface to VGA connector so as to enable the monitor and graphics card to communicate. The first version of the DDC standard was adopted in August 1994. It included the EDID 1.0 format and specified DDC1, DDC2B and DDC2Ab physical links. DDC version 2, introduced in 1996, split EDID into a separate standard and introduced the DDC2B+ protocol. DDC version 3, 1997, introduced the DDC2Bi protocol and support for VESA Plug and Display and Flat Panel Display Interface on separate device addresses. The DDC standard has been superseded by E-DDC in 1999. Extended display identification data (EDID) is a companion standard; it defines a compact binary file format describing the monitor's capabilities and supported graphics modes, stored in a read-only memory (EEPROM) chip programmed by the manufacturer of the monitor.
DDC1 allows the monitor to tell its parameters to the computer. When the VGA graphics card detects data on data-line it starts to read the data coming from the monitor synchronous to vertical sync pulse. Vertical sync pulse frequency can be increased up to 25 KHz for the time of the data transfer if a DDC1 compliant monitor is found (be sure not to send those high frequencies to non DDC1 monitors!).
DDC2 (DDC2B) allows bidirectional communication: monitor can tell its parameters and the computer can adjust monitor settings. The bidirectional data bus is a synchronous data bus similar to Access Bus and is based on I2C technology. The signals in the data bus are standard I2C signals. The computer provides 15 kohm pull-up for the SDA and SCLK lines. Monitor must provide 47 kohm pull-up on SCLK line. DDC2B bus is unidirectional and allows only one bus master - the graphics adapter. The monitor acts as a slave device at the 7-bit I²C address 50h, and provides 128-256 bytes of read-only EDID. Because this access is always a read, the first I²C octet will always be A1h.
E-DDC (Enhanced Display Data Channel) is the most recent revision of the DDC standard. Version 1 was introduced in 1999 and featured up to 32 Kbytes of display information storage for use by the Enhanced EDID (E-EDID) standard. E-DDC Version 1.2, approved in 2007, introduced support for DisplayPort and DisplayID standards
VGA pinout : monitor ID detection pin assignments
This monitor type detection is becoming more and more obsolete nowadays. New VGA plug-and-play monitors communicate with the computer according to VESA DDC standard.
The older VGA pinout with monitor ID is:
| Pin | Name | Dir | Description |
|---|---|---|---|
| 1 | RED | |
Red Video (75 ohm, 0.7 V p-p) |
| 2 | GREEN | |
Green Video (75 ohm, 0.7 V p-p) |
| 3 | BLUE | |
Blue Video (75 ohm, 0.7 V p-p) |
| 4 | ID2 | |
Monitor ID Bit 2 |
| 5 | GND | |
Ground |
| 6 | RGND | |
Red Ground |
| 7 | GGND | |
Green Ground |
| 8 | BGND | |
Blue Ground |
| 9 | KEY | - | Key (No pin) |
| 10 | SGND | |
Sync Ground |
| 11 | ID0 | |
Monitor ID Bit 0 |
| 12 | ID1 | |
Monitor ID Bit 1 |
| 13 | HSYNC or CSYNC | |
Horizontal Sync (or Composite Sync) |
| 14 | VSYNC | |
Vertical Sync |
| 15 | ID3 | |
Monitor ID Bit 3 |
ID pins set-up 4 11 12 ID2 ID0 ID1 n/c n/c n/c no monitor n/c n/c GND Mono monitor which does not support 1024x768 n/c GND n/c Color monitor which does not support 1024x768 GND GND n/c Color monitor which supports 1024x768
GND means connected to ground
n/c means that the pin is not connected anywhere
correct
incorrect