FUNCTION RXD0

SUB TXD0 (expr)

SUB BAUD0 (expr)

DEBUGIN gives the programmer a way to accept strings or numbers from the USB serial port.  In many BASICs this uses INPUT, but in ARMbasic INPUT is used to control the direction of one of the IO pins.  So a simplified replacement of the normal BASIC INPUT has been added, called DEBUGIN.

DEBUGIN has a limited edit capacity: it allows to erase characters using the backspace key. If a better user interface is needed, a custom input routine should be used.

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PRINT will send strings or numbers to the debug serial port (UART0), which may be displayed in BASICtools, or can be interpreted by a user program running on the PC.  Simple formating is accomplished by seperating expressions with a comma (for TAB) or semicolon for no space seperation.  A semicolon at the end of a PRINT suppresses carriage return.

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RXD0 uses the hardware UART, so the CPU is not tied up.  Also when RXD0 is read and no data is available -1 is returned immediately,  RXD0 uses interupts and has a buffer of 256 characters that are filled by interrupt running in the background.

 

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TXD0 uses the hardware serial port to send data out the USB debug port.  Data is transfered into a 16 byte FIFO, when that FIFO is full the CPU will wait until space is available.

 

On the ARMexpress/ARMexpress LITE these routines are all limited to 19.2Kb due to the level translators for RS-232.  If the connection to the ARMexpress/LITE is short (less than a couple inches), then higher baud rates can be used.

 

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Added in version 7.13 --

 

BAUD0 will set the baud rate for TXD0, RXD0, the default is 19.2Kbaud.

 

BAUD1 will set the baud rate for TXD1, RXD1 and will enable that serial channel (in ARMmite these pins are general purpose IOs IO(0)switches to RXD1 and IO(1) switches to TXD1.