Hercules III User Manual Rev A.2
www.diamondsystems.com
Page
31
7. JUMPER CONFIGURATION
The Hercules III board has the following jumper-selectable configuration options.
Jumper Block
Configuration Functions
JP2
COM3 & COM4 RS-422/485 termination
JP3
Digital I/O configuration
JP4
LCD VDD select
JP5
LCD backlight VDD select
JP6
LCD scan direction and frame rate setting
JP7
IRQ & FPGA address Selection
JP9
PC/104-
Plus
VIO selection
JP10
COM3 RS-485/422 pull-up
JP11
COM4 RS-485-422 pull-up
7.1
COM3 & COM4 RS-422/285 Termination (JP2)
JP2 provides 120ohm termination on the D+/D- and RxD_/RxD- lines for COM3 and COM4 RS-422/485
configurations per the following table. The default is no jumpers installed
Pins
Jumper installed
Default
1-2
Pro
vides 120Ω termination between the D+/D- lines in RS-485 mode for COM3
No jumper
3-4
Provides 120Ω termination between the RxD+/RxD- lines in RS-422 mode for COM3
No jumper
5-6
Provides 120Ω termination between the D+/D- lines in RS-485 mode for COM4
No jumper
7-8
Provides 120Ω termination between the RxD+/RxD- lines in RS-422 mode for COM4
No jumper
7.2
Digital I/O Configuration (JP3)
The 40 digital I/O lines have 47Kohm pull resistors that may be configured for pull-up or pull-down with a jumper
per the following table. The default is 47Kohm pull-up.
Pins
Jumper installed
Default
1-3
Provides 47K pull up on DIO lines
Jumper
2-4
Provides 47K pull up on DIO lines
Jumper
3-5
Provides 47K pull down on DIO lines
No jumper
4-6
Provides 47K pull down on DIO lines
No jumper