
SCI to SPI Peripheral Communication in V850ES Microcontrollers
Figure 2. Positive-Edge Data Capture
Data Out
Clock
Data-In
Data Capture Strobe
Master/Slave
Data Drive Strobe
Master/Slave
Figure 3. Timing Specifications for Transmit and Receive Operations
2.2 SPI Communication
A typical MCU master with an SPI unit takes a form similar to NEC Electronics CSI units (Figure 4).
The SPI Mode Control Register specifies the transfer operation (Figure 5). When CPHA = 0, the first
edge of SCK is the data capture strobe for the first bit. Therefore, the slave unit must begin driving its
data before the first edge of SCK. The falling edge of SS_B (slave Chip Select) is used to indicate the
start of transmission. The SS_B must toggle high and then low between transmissions.
5
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