User Manual

Data Sheet / User Manual RB-TW-2400

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There are AC initiated API commands without response (not further Data-Transfer required). In this

case, the indication line as shown in figure 2 will not occur.

RC initiated communication

Also the RC can trigger a communication cycle as shown in fig. 3. This is done by setting the

indication-line. On this indication (or Request) the AC is reading 5+2 Bytes, the Command Bytes.

After the transfer of this 7 Bytes, the AC and or RC may have to prepare the DMAs. The RC indicates

this, removing the ready line during this time. Normally the RC has not to do this, and the Ready line

will not change. When the ready line is set again, the AC can start the data-transfer by sending the

clocks until the communication is done.

After the Data-Transfer the RC resets the ready line again, and prepares the DMA for the next

communication cycle.

Figure 2: Frame structure (Communication triggered by RC)

5.2.2 Communication Cycles (UART)

The API communication can also be done using the UART instead of the SPI. In this case, the

transmitted commands and data are exactly the same as on the SPI. The main difference is the

communication control. As we have a real full duplex communication link, the Indication line and the

ready line are not necessary. The commands and data structures can be transmitted without further

separate lines. Nevertheless, the waiting and evaluation of the command has also to be done on both

sides.