.txbuffsize R/O Property

Function:	For the selected serial port (selection is made through ser.num), returns current TX buffer capacity in bytes.
Type:	Word \| dword
Value Range:	0-65535
See Also:	Buffer Memory Status

Details

Buffer capacity can be changed through the ser.txbuffrq method followed by the sys.buffalloc method.

The ser.txbuffrq method requests the buffer size in 256-byte pages, whereas this property returns buffer size in bytes. The relationship between the two is as follows: ser.txbuffsize = num_pages * 256 - X (or = 0 when num_pages = 0), where "num_pages" is the number of buffer pages GRANTED through ser.txbuffrq. The "- X" is because a number of bytes is needed for internal buffer variables. X = 17 bytes on 16-bit platforms and 33 bytes on 32-bit platforms. The platform type is specified in your platform documentation.

Older devices had smaller RAM sizes, so the value returned by this property was of the word type. On newer devices with larger RAM capacities, this property has the dword type. Inspect the property's declaration on the platform you are using to make sure you know its type.