Data Transfers

The SPI Receive control register, SPIRCON (9CH), controls the data receive operation. The receive buffer can be flushed with the write only RXFLUSH bit. A flush operation changes the SPI receive pointer so that it points to the same address as the FIFO IN pointer, and clears the receive counter. The receive counter indicates the number of bytes that have been received. An interrupt can be generated when the receive count equals or exceeds a chosen num- ber. If the interrupt is not masked in the AISTAT register, the SPI received inter- rupt will cause a AI interrupt. The PPIRQ register is used in the AI interrupt rou- tine to determine the source of the interrupt. The SPI receive interrupt can be monitored in the AISTAT register.

The SPI Transmit control register, SPITCON (9DH), controls the data transmit operation. The transmit buffer can be flushed with the write only TXFLUSH bit. A flush operation changes the SPI transmit pointer so that it points to the same address as the FIFO OUT pointer, and clears the transmit counter. The trans- mit counter indicates the number of bytes in the transmit buffer (FIFO and buff- er). An interrupt can be generated when the transmit count is less than or equal to a chosen number. If the interrupt is not masked in the AISTAT register, the SPI transmit interrupt with cause a auxiliary interrupt. The SPI transmit inter- rupt can be monitored in the AISTAT register.

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Texas Instruments MSC1210 manual 13-8