ZBA Inc. BT44-291S Benutzerhandbuch
BT44-291S
Page 10 of 18
in Figure 11.13. If tBRK is longer than the value, defined by the PS Key
PSKEY_HOST_IO_UART_RESET_TIMEOUT, (0x1a4), a reset will occur.
PSKEY_HOST_IO_UART_RESET_TIMEOUT, (0x1a4), a reset will occur.
This feature allows a host to initialise the system to a known state. Also, BlueCore4-External
can emit a Break character that may be used to wake the Host.
Note:
The DFU boot loader must be loaded into the Flash device before the UART or USB
interfaces can be used.This initial flash programming can be done via the SPI.
Table 11.3 shows a list of commonly used Baud rates and their associated values for the
Persistent Store Key PSKEY_UART_BAUD_RATE (0x204). There is no requirement to use these
standard values. Any Baud rate within the supported range can be set in the Persistent Store Key
according to the formula in Equation 11.7.
standard values. Any Baud rate within the supported range can be set in the Persistent Store Key
according to the formula in Equation 11.7.
Baud Rate = PSKEY_UART_BAUD_RATE / 0.004096
Equation 11.7: Baud Rate
Persistent Store Value
Baud Rate
Hex Dec
Error
1200 0x0005 5 1.73%
2400 0x000a 10 1.73%
4800 0x0014 20 1.73%
9600 0x0027 39 -0.82%
2400 0x000a 10 1.73%
4800 0x0014 20 1.73%
9600 0x0027 39 -0.82%
19200 0x004f 79 0.45%
38400 0x009d 157 -0.18%
57600 0x00ec 236 0.03%
76800 0x013b 315 0.14%
38400 0x009d 157 -0.18%
57600 0x00ec 236 0.03%
76800 0x013b 315 0.14%
115200 0x01d8 472 0.03%
230400 0x03b0 944 0.03%
460800 0x075f 1887 -0.02%
921600 0x0ebf 3775 0.00%
230400 0x03b0 944 0.03%
460800 0x075f 1887 -0.02%
921600 0x0ebf 3775 0.00%
1382400 0x161e 5662 -0.01%
1843200 0x1d7e 7550 0.00%
2764800 0x2c3d 11325 0.00%
1843200 0x1d7e 7550 0.00%
2764800 0x2c3d 11325 0.00%
Table 11.8: Standard Baud Rates