LMX9830SM National Semiconductor, LMX9830SM Datasheet - Page 16

• Manufacturer Part Number: LMX9830SM
• Manufacturer: National Semiconductor

Specifications of LMX9830SM

• Lead Free Status / Rohs Status: Not Compliant

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Osc Freq. (MHz)
10-20 (Note 38)
Note 35: If OP3 is 1, must use 1k Ω pull up.
Note 36: If OP4 is 1, must use 1k Ω pull up.
Note 37: If OP5 is 1, must use 1k Ω pull up.
Note 38: Supported frequencies see Table 21.
9.6.4 Configuring the LMX9830 Through Transport Layer
As described in Section 9.5 SYSTEM POWER UP, the
LMX9830 will check during startup the Options Registers if an
external PROM is available. If the information on the PROM
are incomplete or no PROM is installed the LMX9830 will boot
into the “initialization Mode”.
The mode is confirmed by the “Await Initialization” Event.
The following information are needed to enter Bluetooth
Mode:
•
•
•
In general the following procedure will initialize the LMX9830:
1.
2.
3.
4.
Note: In case no EEPROM is used, BDAddr, clock source and Baudrate are
Bluetooth Device Address (BD_Addr)
External clock source (only if 10 - 20 MHz has been
selected)
UART Baudrate (only if Auto baudrate detection has been
selected)
Wait for “Await initialization” Event
— Event will only appear if transport layer speed is set
or after successful baudrate detection.
Send “Set Clock and Baudrate” Command only if the
clock speed is not known through hardware
configuration (i.e only if OP3, OP4, OP5 = 0 1 0).
Send “Write BD_Addr” to Configure Local Bluetooth
Device Address.
Send “Enter Bluetooth Mode”
— LMX9830 will use configured clock and UART speed
and start the command interface.
12
13
13
13
13
only valid until the next power-cycle or hardware reset.
10-20 (Note 35)
BBCLK (MHz)
12
13
13
13
13
PLL (48 MHz) OP3 (Note 35) OP4 (Note 36) OP5 (Note 37)
FIGURE 3. Auto Baudrate Detection Timing Diagram
OFF
OFF
OFF
OFF
OFF
ON
TABLE 17. Fixed Frequencies
0
0
1
1
1
1
16
9.6.5 Auto Baud Rate Detection
The LMX9830 supports an Automatic Baudrate Detection in
case the external clock is different to 12, 13MHz or the range
10-20 MHz or the baudrate is different to 9.6 kbps, 115.2 or
921.6 kbit/s.
The baudrate detection is based on the measurement of a
single character. The following issues need to be considered:
•
•
•
•
•
•
The flow control pin CTS must be low or else the host is in
flow stop.
The Auto Baudrate Detector measures the length of the
0x01 character from the positive edge of bit 0 to the
positive edge of stop bit.
Therefore the very first received character must always be
a 0x01.
The host can restrict itself to send only a 0x01 character
or also can send a command.
The host must flush the TX buffer within 50-100
milliseconds depend on clock frequency on the host
controller.
After 50-100 milliseconds the UART is about to be
initialized and short after the host should receive a “Await
Initialization” Event or an “Command Status” Event.
0
1
0
0
1
1
0
0
0
1
0
1
UART speed read from NVS
Clock and UART baudrate
detection
UART speed read from NVS
UART speed 9.6 kbps
UART speed 115.2 kbps
UART speed 921.6 kbps
Function
20180011