19.10 Uart0, Uart1 Application Example - Fujitsu MB90390 Series Hardware Manual

CHAPTER 19 UART0, UART1

19.10 UART0, UART1 Application Example

Mode 2 is used when a number of slave CPUs are connected to a host CPU (see Figure
19.10-1.)
■ Application Example
SIN0 input
RBF
RDRF, PE, ORFE
As shown in Figure 19.10-2, communication starts with the host CPU transmitting address data. The ninth
bit (D8) of the address data is set to "1". The address selects the slave CPU with which communication will
be established. The selected slave CPU communicates with the host CPU using a protocol determined by
the user. In normal data, D8 is set to "0". Unselected slave CPUs wait in standby until the next
communication session starts. Figure 19.10-3 shows the communication flowchart for mode 2 operation.
Because the parity check function is not available in this mode, set the PEN bit in the UMC register to "0".
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Figure 19.10-1 RBF Set Timing (Mode 0)
ST D0 D1
ST: Start bit D0 to D7: Data bits
Figure 19.10-2 Example System Configuration Using Mode 2
SOT0
SIN0
Host CPU
SOT0 SIN0
Slave CPU #0
D2 D3 D4 D5 D6 D7
SP: Stop bit
SOT0 SIN0
Slave CPU #1
SP