In One-Wire mode, the programmer/debugger and UPDI can be totally out of synch, requiring a worst-case length for the BREAK character to be sure that the UPDI can detect it. Assuming the slowest UPDI clock speed of 4 MHz (250 ns), the maximum length of the 8-bit SYNCH pattern value that can be contained in 16 bits is
UPDICLKSEL[1:0] | Recommended BREAK Character Duration |
---|---|
0x1 (16 MHz) |
6.15 ms |
0x2 (8 MHz) |
12.30 ms |
0x3 (4 MHz) |
24.60 ms |