Rainbow-electronics DS1339 Manual de usuario descargar pdf (Pagina 12)

DS1339

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Figure 7. DATA TRANSFER ON 2-WIRE SERIAL BUS

Depending upon the state of the R/ W bit, two types of data transfer are possible:

1) Data Transfer from a Master Transmitter to a Slave Receiver. The first byte transmitted by the

master is the slave address. Next follows a number of data bytes. The slave returns an acknowledge

bit after each received byte. Data is transferred with the most significant bit (MSB) first.

2) Data Transfer from a Slave Transmitter to a Master Receiver. The first byte (the slave address) is

transmitted by the master. The slave then returns an acknowledge bit. This is followed by the slave

transmitting a number of data bytes. The master returns an acknowledge bit after all received bytes

other than the last byte. At the end of the last received byte, a “not acknowledge” is returned. The

master device generates all of the serial clock pulses and the START and STOP conditions. A transfer

is ended with a STOP condition or with a repeated START condition. Since a repeated START

condition is also the beginning of the next serial transfer, the bus is not released. Data is transferred

with the MSB first.

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Rainbow-electronics DS1339 Manual de usuario Pagina 12