User Manual

RA01
Version: 1.0 Date: 10/8/2008
Tel: [phone] Fax: [phone] E-mail: [e-mail] http://www.hoperf.com
14
10. Extended Features Command
bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 POR
1 0 1 1 0 0 0 0 exlp ctls 0 dcal bw1 bw0 f5 f4 B0CAh
Bit 7 < exlp >: Enables low power mode for the crystal oscillator.
Bit 6 <
ctls >: Clock tail selection bit. Setting this bit selects 512 bit long clock tail instead of the default 128 bit length.
Bit 4 <
dcal >: Disables the wake-up timer auto calibration.
Bit 3-2 <
bw1:bw0 >: Select the bandwidth of the PLL.
bw1 bw0 PLL bandwidth
0 0 15 kHz
0 1 30 kHz
1 0 60 kHz
1 1 120 kHz
Bit 1-0 < f5:f4 >: Upper two bits for selecting the 64 bit FIFO IT level together with the f3-f0 bits in the Output and
FIFO Mode Command.
11. Low Duty Cycle Command
bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 POR
1 0 1 1 0 0 0 0 d6 d5 d4 d3 d2 d1 d0 enld B0CAh
Bit 7-1 < d6:d1 >: The Duty-Cycle can be calculated by using D ( d6 to d0 ) and M. (M is parameter in a Wake-Up
Timer Command
.)
Duty-Cycle= (D * 2 +1) / M *100%
Bit 0 <
enld >: Enables the low duty cycle operation of the receiver.
12. Demodulator Setting Command
bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 POR
1 0 1 1 0 0 0 0 tc1 tc0 0 0 0 0 0 0 D000h
Bit 7-6 < tc1:tc0 >: Select the time constant of the demodulator
tc1 tc0 Time constant
0 0 Fast
1 1 Middle
1 0 Slow
1 1 Reserved
The table shows the optimal filter capacitor values for different popular data rates:
Data Rate [kbps] Manchester 2.4 4.8 9.6 19.2 38.4 >38.4
Data Rate [kbps] NRZ - 2.4 4.8 9.6 19.2 >19.2
Recommended Capacitor on pin15 ( FILC) [pF] 330 330 220 100 27 0
Optimal <tc1:tc0> setting Slow Slow Middle Middle Fast Fast
Note: Manchester coding doubles the bandwidth requirement compared to NRZ.