HT9480 datasheet(26/57 Pages) HOLTEK

26 / 57 page

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.

• Pager data address

The pager data address (1FH) are the parallel

data lines for decoder data transfer.

Symbol

Bit

R/W

Description

0R/W

On/Off control bit

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

0: ON state

1: STANDBY state

RES

1R/W

Reset output for the decoder core

The

µC 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

µC 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; otherwise 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.

6R/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

µC 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 serial data is changed to parallel data (1FH). After reading the

parallel data, the

µC software has to set the DR bit high.

HT9480

23th Feb ’98

HT9480 Datasheet(PDF) 26 Page - Holtek Semiconductor Inc

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