Data Sheet
AC4490
Datasheet
https://www.lairdconnect.com/
15
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Data Bits
Parity
Stop Bits
Transceiver Programming Requirements
7
E, O, M, S
1
Parity Disabled
9
N
1
Parity Enabled
8
N
2
Parity Enabled
8
E, O, M, S
1
Parity Enabled
7
E, O, M, S
2
Parity Enabled
Mark (M) corresponds to 1 & Space (S) corresponds to 0
6.4 Serial Interface Baud Rate
This two-byte value determines the baud rate used for communicating over the serial interface between the OEM Host and the
transceiver. This rate is independent of the RF baud rate, which is fixed at 76.8 Kbps. Table 6 lists values for some common
baud rates.
Note: Baud rates below 1200 baud are not supported.
For a baud rate to be valid, the calculated baud rate must be within ±3% of the OEM host baud rate. If the Test pin (pin 12) is
pulled Logic Low at reset, the baud rate will be forced to 9600. For baud rate values other than those shown in Table 6, the
following equations can be used:
Table 6: Baud Rate / Interface Timeout
Baud Rate
BaudL (0x42)
BaudH (0x43)
Minimum Interface Timeout
(0x58)
Stop Bit Delay
(0x3F)
115200
0xFE
0x00
0x02
0xFF
57600
1
0xFC
0x00
0x02
0x03
38400
0xFA
0x00
0x02
0x08
28800
0xF8
0x00
0x02
0x0E
19200
0xF4
0x00
0x03
0x19
14400
0xF0
0x00
0x04
0x23
9600
0xE8
0x00
0x05
0x39
4800
0xD0
0x00
0x09
0x7A
2400
0xA0
0x00
0x11
0xFC
1200
0x40
0x00
0x21
0x00
2
1. 57600 is the default baud rate
2. 0x00 yields a stop bit of 421 µSec. The stop bit at 1200 baud should be 833 µSec.
6.4.1 OEM Host Data Rate
The OEM host data rate is the rate with which the OEM host and transceiver communicate over the serial interface. This rate
is independent of the RF baud rate, which is fixed at 76.8 Kbps. Possible values range from 1200 bps to 115200 bps.