Service manual

RX-E200

Microprocessor peripheral circuit

Transmission

Reception

CPU

System cable

Description of data transmission and reception

q Although there is only 1 bus line, prepare special ports

for data transmission and reception at each CPU.

w The bus data consists of a header and data (8 bits).

CPU receives and transmits at a 0.5mS or less timer

interruption.

e The header is used to identify the model and to

prevent butting by changing the length for each unit.

r At each CPU, data transmission and reception are

carried out independently. Before transmitting the data,

be sure to check the reception status. If the data is being

received, wait until the data has been received and then

transmit the data.

t When the data transmission is completed, each CPU

also checks the received data. If the header of the

received data does not agree with its own head, the data

may have been overlapped by that of the other model. In

such case, stop the data transmission and restart it after

confirming that the the data transmission of other model

has been completed. This means that the unit with a

longer header has a higher priority.

Description of main system operation

1) POWER ON/OFF processing [(1) to (4)]

RX CDX MDX KX

• The power cord of each unit is connected to the AC outlet in series and switched on and off

through the RX relay.

• Turning off the RX power switch will turn off the power to other units (primary connection) but

turning off the power switch of any other unit will turn off the secondary connection of each unit

only (i.e., the microprocessor remains on).

• Each unit has a backup function to save the secondary connection status when unplugged

(taking use of a unit alone into consideration)

• The indicators of units are turned on after a dimmer level signal is fed from RX so that they light

up simultaneously when the RX power switch is turned on. However, as the indicator of a unit

does not light up when the unit is used alone in this setting, the indicator is forced to turn on when

2 seconds have elapsed without a dimmer level signal being fed (and the power for the backup

function is turned on). When the CD unit is used alone, the timer play mode is set regardless of

the backup function status.

• Make sure that the power off processing of each unit has been completed before turning off the

power by using the RX relay.

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