System Installation
ROBO-8716VG2A User’s Manual
3-9
3.6 GPIO
The ROBO-8716VG2A provides 4 input/output ports that can be individually
configured to perform a simple basic I/O function. Users can configure each
individual port to become an input or output port by programming register bit of
I/O Selection. To invert port value, the setting of Inversion Register has to be made.
Port values can be set to read or write through Data Register.
Additionally, 4-extra Digital Output ports inversely amplified signals from GPIO
ports. There are open-drain buffers, which can offer greater driving capacity up to
100mA.
J8: 8-Bit GPIO Header
PIN No.
Signal Description
1
General Purpose I/O Port 1 (GPIO14)
2
General Purpose I/O Port 2 (GPIO15)
3
General Purpose I/O Port 3 (GPIO16)
4
General Purpose I/O Port 4 (GPIO17)
5 GND
6 DO1
7 DO2
8 DO3
9 DO4
10 +5V
There are two PNP I/O port addresses that can be used to configure GPIO ports,
1) 0x2E - EFER (Extended Function Enable Register, for entering Extended Function
Mode)
- EFIR (Extended Function Index Register, for identifying CR index number)
2) 0x2F - EFDR (Extended Function Data Register, for accessing desired CR)
Below are some example codes, which demonstrate the use of GPIOs.
// Enter Extended Function Mode
outp(0x002E, 0x87);
outp(0x002E, 0x87);
// Assign Pin121-128 to be GPIO port 1
outp(0x002E, 0x2A);
outp(0x002F, inp(0x002F) | 0x84);
// Select Logic Device 7
outp(0x002E, 0x07);
outp(0x002F, 0x07);
