busy=idle, tfnf=full, rff=not_full, tfe=not_empty, rfne=empty
UART Status Register
busy | UART Busy Bit 0 (idle): undefined 1 (busy): undefined |
tfnf | TX FIFO Not Full 0 (full): undefined 1 (not_full): undefined |
tfe | TX FIFO Empty 0 (not_empty): undefined 1 (empty): undefined |
rfne | RX FIFO Not Empty 0 (empty): undefined 1 (not_empty): undefined |
rff | RX FIFO Full 0 (not_full): undefined 1 (full): undefined |