ENC28J60 Transmit Buffer over-sized

[nielsonm236]

While digging deep into the ENC28J60 code I find that the Transmit Buffer is over-sized, and the buffer space in the ENC28J60 could be better utilized if re-allocated to the Receive Buffer. Some notes:

• The Receive Buffer is a circular buffer to allow the ENC28J60 to queue incoming Ethernet packets for later processing by firmware.
• The Transmit Buffer is a "one packet at a time" buffer. All transmit queueing is done in firmware.
• Due to the small RAM size of the STM8 processor the maximum frame size set by the HW-584 is 550 bytes. So, the Transmit Buffer doesn't need to be any larger than that value..
• The Receive Buffer size is currently set at 6144 bytes. The Transmit Buffer is currently set at 2048 bytes.
• Suggestion: Increase the Receive Buffer by 1490 bytes (and decrease the Transmit Buffer by 1490 bytes).