MICRF219 datasheet(10/23 Pages) MICREL

10 / 23 page

Micrel

MICRF219

June 2011

M9999-060811

(408) 944-0800

low

the

circ

od.

regis

14 to set the

re used for control

re u

g, s

bits

p for the programmed timer du

data if it is present.

is se

ep peri

the

al re

r of bits to

be checked as good, before the receiver outputs data

at the DO pin. The bit-check window bits D9, D10,

D11 must also be set to match the data period. The

shortest default window time gives the least critical bit

check action. For better discrimination, the window

setting may be increased up towards the normal

minimum time expected between data edges. Note

an this will result in all

e device will remain in

n the serial command

go to sleep for the

e to receive and check

a again at DO as soon

f good RTZ bits have

seen, the device will

gain for good bits after

the sleep period.

Both high and low periods are

nable the device

e device to sleep.

er a programmable

rence frequency. If

the next pulse edge falls within this window the bit is

d and

sufficient pulses have

or a lack of pulses will

ep for a further sleep

od.

Squelch

During normal operation, if four or less out of eight bit

pulses are good, the DO output is squelched. If good

bit count increases to seven or more in any eight

sequential bits, squelch is disabled allowing data to

output at DO pin.

Auto-Polling

The auto-poll block (Figure 3) contains a

oscillator that drives the sleep timer when

the device is powered down. It also contains

check whether the received bits are go

polling is controlled by bit D15 in the serial

conjunction with bits D12, D13, D

power

rest of

uits to

Auto-

ter, in

sleep

of the

sed to

device will stay awake until serial bit D15

then set high again, to enable a further sle

The sleep duty cycle may be controlled by

of serial commands.

Auto-Polling with Bit-Checking

For auto-polling with bit-checking, the seri

bits D7and D8 need to be set for the numbe

that a window time set longer th

bits being tested as bad and th

sleep polling mode. Now, whe

sets bit D15 high, the device will

timer period and will then awak

bits. The device will output dat

as the programmed numbers o

been received. If a bad bit is

return to sleep mode and poll a

timer period. Bits D7, D8, a

bit-check operation and bits D9, D10, D11 a

adjust the sensitivity of the bit-check action.

Auto-Polling without Bit-Checking

For simple auto-polling without bit-checkin

serial command with bit D15 set high and

D13, D14 set to the desired sleep time. T

will go to slee

end a

D12,

device

ration

The

t low,

checked for each RTZ bit. The device will continue to

check bits until sufficient good bits e

to wake up, or bad bits return th

Operation

Received pulse edges trigg

window timer clocked by the refe

then wake up to receive

od.

timing

gister

flagged as bad. Detected good bits are counte

the device will wake up once

been received. Two bad pulses

cause the device to go to sle

timeout peri

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