7
USB930HXADBD ADAPTER BOARD USER’S GUIDE
The flexibility of frequency changes for power saving has a direct impact on baud rate and serial
communication. To allow debugging sessions without risk of board-PC communication loss, a
number of changes have been added to the RISM code. To establish communication between the
evaluation board and the debugger (Keil, PLC, or Tasking software) use either the external serial
link (recommended) or the internal serial link.
4.6.1
Using the External Serial Port
You are encouraged strongly to use the external serial port to communicate with the debugger
environment. When this serial port is used, the baud rate is 19200 (make sure you set the debugger
software to use the same rate) and all internal timers are available. The internal serial port is then
free and can be used by your application. One interrupt (intr0), however, is used by the UART
and cannot be used. The priority should not be changed.
The external serial port is labeled “UART” on the board To enable this port, set the UARTC
switch to the “ON” position.
When using this port, you can set or clear the LC bit using the SETB and CLR instructions. There
are no restrictions to your code.
4.6.2
Using the Internal Serial Port
The use of the internal serial port to communicate with the debugger is not recommended. When
you use this serial port, the baud rate is fixed at 9600 (you must set the debugger software to use
the same rate) and timer-two is used by the RISM to generate the baud rate, making this timer
unavailable for your application. The internal serial port is no longer available since it used to
communicate with the debugger. Do not change the interrupt priority. The external interrupts,
intr0 and intr1, are both available.
When using this port, you can still set or clear the LC bit. However, you cannot use the SETB and
CLR instructions to do. So you must use an extended call to a routine inside the RISM that sets
or clears the bit. Instead of using “SETB LC” you must use “ECALL 0FF0083” and instead of
using “CLR LC” use “ECALL 0FF008B”.
5.0
8X930XX ADAPTER BOARD SCHEMATICS
The pages that follow provide you with schematics for the adapter board. These files are also
available on the Intel World-Wide Web sit at
www.intel.com
.
