atr2434 ATMEL Corporation, atr2434 Datasheet - Page 13

• Manufacturer Part Number: atr2434
• Description: Wirelessusb 2.4-ghz Dsss Radio Soc - Atmel Corporation
• Manufacturer: ATMEL Corporation

Table 7. Data Rate
4822C–ISM–09/04
Bit
7:3
2
1
0
Note:
(1)
(1)
(1)
7
Name
Reserved
Code
Width
Data Rate
Sample
Rate
1. The following Reg 0x04, bits 2:0 values are not valid:
Addr: 0x04
· 001-Not Valid
· 010-Not Valid
· 011-Not Valid
· 111-Not Valid
Description
These bits are reserved and should be written with zeros.
The Code Width bit is used to select between 32 chips/bit and 64 chips/bit PN codes.
1 = 32 chips/bit PN codes
0 = 64 chips/bit PN codes
The number of chips/bit used impacts a number of factors such as data throughput, range and robustness to
interference. By choosing a 32 chips/bit PN-code, the data throughput can be doubled or even quadrupled
(when double data rate is set). A 64 chips/bit PN code offers improved range over its 32 chips/bit counterpart as
well as more robustness to interference. By selecting to use a 32 chips/bit PN code a number of other register
bits are impacted and need to be addressed. These are PN Code Select (Reg 0x03, bit 5), Data Rate (Reg
0x04, bit 1), and Sample Rate (Reg 0x04, bit 0).
The Data Rate bit allows the user to select a Double Data Rate mode of operation which delivers a raw data rate
of 62.5 kbits/sec.
1 = Double Data Rate - 2 bits per PN code (No odd bit transmissions)
0 = Normal Data Rate - 1 bit per PN code
This bit is applicable only when using 32 chips/bit PN codes which can be selected by setting the Code Width bit
(Reg 0x04, bit 2 = 1). When using the Double Data Rate, the raw data throughput is 62.5 kbits/s because every
32 chips/bit PN code is interpreted as 2 bits of data. When using this mode a single 64 chips/bit PN code is
placed in the PN code register. This 64 chips/bit PN code is then split into two and used by the baseband to
offer the Double Data Rate capability. When using the Normal Data Rate, the raw data throughput is
32 kbits/sec. Additionally, Normal Data Rate enables the user to potentially correlate data using two differing 32
chips/bit PN codes.
The Sample Rate bit allows the use of the 12 ×sampling when using 32 chips/bit PN codes and the Normal Data
Rate.
1 = 12 × Oversampling
0 = 6 × Oversampling
Using 12 × oversampling improves the correlators receive sensitivity. When using 64 chips/bit PN codes or the
Double Data Rate this bit is do not care. When in the Normal Data Rate setting and choosing 12 ×
oversampling, eliminates the ability to receive from two different PN codes. Therefore the only time when 12 ×
oversampling is to be selected is when a 32 chips/bit PN code is being used and there is no need to receive
data from sources with two different PN codes.
6
Reserved
5
REG_DATA_RATE
4
3
ATR2434 [Preliminary]
Code Width
2
Data Rate
1
Default: 0x00
Sample Rate
0
13