Chapter 3 | Hardware |
for the serial port 1. As an alternate, you can short the equivalent pins (pins 7 and 9) on the respective DB9 port connector as shown in Figure
Serial A Interface (J11) | 19 | 9 7 5 3 1 | 1 | 2 | 3 | 4 | 5 | |
| Or | Standard DB9 Serial |
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for Serial Port 1 |
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(or COM1 Port) |
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| Port Connector (Female) |
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20 | 10 8 6 4 2 | Rear View |
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Top View | 6 | 7 | 8 | 9 | ||||
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Figure 3-3. Hot Cable Jumper
LB550Hotcable
Watchdog Timer
The watchdog timer (WDT) restarts the system if a mishap occurs, ensuring proper
The WDT (watchdog timer) can be used both during the boot process and during normal system operation.
•During the Boot process – If the operating system fails to boot in the time interval set in the BIOS, the system will reset.
Enable the WDT in the Advanced BIOS Features of BIOS Setup. Set the WDT for a
•During System Operation – An application can set up the WDT hardware through a BIOS call, or by accessing the hardware directly. Some Ampro Board Support Packages provide an API interface to the WDT. The application must tickle (turnoff) the WDT in the time set when the WDT is initialized or the system will be reset. You can use a BIOS call to tickle the WDT or access the hardware directly.
The BIOS implements interrupt 15 function 0C3h to manipulate the WDT.
•Watchdog Code examples – Ampro has provided source code examples on the LittleBoard 550 Doc & SW
60 | Reference Manual | LittleBoard 550 |