HT9480 datasheet(21/47 Pages) HOLTEK

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HT9480

Rev. 1.20

July 31, 2002

The function bits (ON, RES) and indication bits (CT, STB, BF,OR,BL and DR) are all used to control the status of the

decoder which is operated through the pager control address as described in the following table.

Symbol

Bit

R/W

Description

R/W

On/Off control bit

This bit selects the ON or STANDBY state of the decoder.

0: ON state

1: STANDBY state

RES

R/W

Reset output for the decoder core

The MCU has to set the RES bit low and then high after the pager controller is turned on.

Call termination indication bit

This bit decides the call termination status, when a valid code-word is received

0: End of code-word receive

1: Receiving message code-word

STB

Standby indication bit

When the value of the ON bit is 1, the system goes into the STANDBY state. The

STANDBY state allows the MCU to execute the configuration RAM setting.

Battery fail indication bit

Once the decoder detects that the battery fail interrupt is low, the BF bit will be low but

unlatched.

Out-of-range indication bit

Whenever the decoder detects an out-of-range condition, this bit is cleared low after

end of the programmed out-of-range hold of time that is selected by the configuration

registers (SPF06 and SPF07). The out-of-range indication may be tested for an

out-of-range condition whenever the interface enable of the decoder is active; other-

wise the OR is normally high. The out-of-range indication is set high by detection of a

valid data transmission or by switching the decoder to be in the STANDBY state.

R/W

Battery low indication bit

The battery low indication is periodically tested for a battery low condition. If the decoder

encounters a battery low condition the battery low indication bit is cleared low. At this time,

the MCU should set the BL bit high.

R/W

Data ready interrupt indication bit

When a valid call is detected, data starts transfer. The DR bit becomes low when the se-

rial data is changed to parallel data (1FH). After reading the parallel data, the MCU soft-

ware has to set the DR bit high.

· Pager data address

The pager data address (1FH) are the parallel data lines for decoder data transfer.

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