T5760 Ver la hoja de datos (PDF) - Atmel Corporation

Número de pieza

componentes Descripción

Fabricante

T5760

UHF ASK/FSK Receiver

Atmel Corporation 

T5760 / T5761

( Lim_min = 14, Lim_max = 24 )

IC_ACTIVE

Bit check ok

Bit check ok

Bit check

Dem_out

Bit–check–

counter

1/2 Bit

1/2 Bit

1/2 Bit

0

1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1 2 3 4

TStart–up

Start–up mode

TXClk

TBit–check

Bit–check mode

Figure 11. Timing diagram during bit check

( Lim_min = 14, Lim_max = 24 )

IC_ACTIVE

Bit check failed ( CV_Lim < Lim_min )

Bit check

Dem_out

Bit–check–

counter

1/2 Bit

0

1 2 3 4 5 6 1 2 3 4 5 6 7 8 9 10 11 12

TStart–up

TBit–check

Start–up mode

Bit–check mode

0

TSleep

Sleep mode

Figure 12. Timing diagram for failed bit check (condition: CV_Lim < Lim_min)

( Lim_min = 14, Lim_max = 24 )

Bit check failed ( CV_Lim >= Lim_max )

IC_ACTIVE

Bit check

Dem_out

Bit–check–

counter

1/2 Bit

0

TStart–up

1 2 3 4 5 6 7 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

TBit–check

Start–up mode

Bit–check mode

0

TSleep

Sleep mode

Figure 13. Timing diagram for failed bit check (condition: CV_Lim >= Lim_max)

Duration of the Bit Check

If no transmitter signal is present during the bit check, the

output of the ASK/ FSK demodulator delivers random

signals. The bit check is a statistical process and TBit-check

varies for each check. Therefore, an average value for

TBit-check is given in the electrical characteristics.

TBit-check depends on the selected baud-rate range and on

TClk. A higher baud-rate range causes a lower value for

TBit-check resulting in a lower current consumption in pol-

ling mode.

In the presence of a valid transmitter signal, TBit-check is

dependent on the frequency of that signal, fSig, and the

count of the checked bits, NBit-check. A higher value for

NBit-check thereby results in a longer period for TBit-check

requiring a higher value for the transmitter pre-burst

TPreburst.

Receiving Mode

If the bit check was successful for all bits specified by

NBit-check, the receiver switches to receiving mode. Ac-

cording to figure 9, the internal data signal is switched to

Pin DATA in that case and the data clock is available after

the start bit has been detected (figure 20). A connected µC

can be woken up by the negative edge at Pin DATA or by

the data clock at Pin DATA_CLK. The receiver stays in

that condition until it is switched back to polling mode ex-

plicitly.

10 (32)

Preliminary Information

Rev. A2, 19-Oct-00

Share Link: