User's Manual

9/29/2004 OV4F2
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BCM2035 User Manual
04/23/03
Broadcom Corporation
Page 18 Peripheral Transport Unit Document 2035-UM100-R
The baud rate of the BCM2035 UART is expressed as:
24 MHz/((16xUART Clock Divisor) + Total Inserted 24 MHz Clock Cycles)
Normally, the UART baud rate will be set by the parameters stored in the optional serial EEPROM, or by
automatic baud rate detection and the host will not need to adjust the baud rate. Support for changing the baud
rate during normal HCI UART operation is included through a Vendor Specific command that allows the host
to adjust the contents of the baud rate registers.
The
BCM2035 UART will operate correctly with the Host UART as long as the combined baud rate error of the
two devices is within ± 5%.
Auto-Baud Rate Detection
If no EEPROM is connected to the
BCM2035 containing UART configuration information, the BCM2035 may
be put into a state where it will attempt to automatically detect the baud rate. A 'U' character (Hex 0x55) is sent
from the Host to train the
BCM2035 UART when this feature is used.