z8fmc16100 ZiLOG Semiconductor, z8fmc16100 Datasheet - Page 254

• Manufacturer Part Number: z8fmc16100
• Description: Z8 Encore Motor Control Flash Mcus
• Manufacturer: ZiLOG Semiconductor

PS024611-0408
OCD Auto-Baud Detector/Generator
OCD Serial Errors
To run over a range of baud rates (bps) with various system clock frequencies, the OCD
has an Auto-Baud Detector/Generator. After a reset, the OCD is idle until it receives data.
The OCD requires that the first character sent from the host is the character
acter
Baud Detector measures this period and sets the OCD Baud Rate Generator accordingly.
The Auto-Baud Detector/Generator is clocked by the system clock. The minimum baud
rate is the system clock frequency divided by 512. The maximum recommended baud rate
is the system clock frequency divided by 8.
maximum baud rates for sample crystal frequencies.
Table 133. OCD Baud-Rate Limits
If the OCD receives a Serial Break (ten or more continuous bits Low) the Auto-Baud
Detector/Generator resets. The Auto-Baud Detector/Generator can then be reconfigured
by sending
character, the Auto-Baud Detector will remain reset.
The OCD detects any of the following error conditions on the DBG pin:
•
•
•
When the OCD detects one of these errors, it aborts any command currently in progress,
transmits a Serial Break 4096 system clock cycles long back to the host, and resets the
Auto-Baud Detector/Generator. A Framing Error or Transmit Collision can be caused by
the host sending a Serial Break to the OCD. Due to the open-drain nature of the interface,
returning a Serial Break back to the host only extends the length of the Serial Break , if the
host releases the Serial Break early.
Serial Break (a minimum of ten continuous bits Low)
Framing Error (received STOP bit is Low)
Transmit Collision (OCD and host simultaneous transmission detected by the OCD)
80h
System Clock
32.768 kHz
Frequency
20.0 MHz
1.0 MHz
contains eight continuous bits Low (one Start bit plus 7 data bits). The Auto-
80h
. If the Auto-Baud Detector overflows while measuring the Auto-Baud
Maximum Asynchronous
Baud Rate (bps)
125 K
2.5 M
4096
Table 133
lists minimum and recommended
OCD Auto-Baud Detector/Generator
Product Specification
Baud Rate (bps)
Minimum
39.1 K
1960
64
80h
. The char-
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