V_GS,LOW  = V_DD - (V_DD - V_CC - V_TVS) * (R2 / (R1 + R2)) 
V_GS,HIGH = V_DD - V_DD * (R2 / (R1 + R2))

V_DD = 0.6 * (1 + R1 / R2) = 0.6 * (1 + 100 / 5.1) = 12.4
V_GS,LOW  = 12.4 - (12.4 - 5 - 0.7) * (100 / (100 + 10)) = 0.6 V
V_GS,HIGH = 12.4 - 12.4 * (100 / (100 + 10)) = 1.13 V

Default stdio driver flushes after newline. May sleep for 50ms
when the tx fifo is full, but generally unbuffered.