Example Of Protocol Using Autotransmit Mode - Texas Instruments OMAP5910 Technical Reference Manual

7.4.5

Example of Protocol Using Autotransmit Mode

8) Wait for the CSRB bit of the control and status register (CSR) to be reset.
9) Load the transmit data register (TDR) with:
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D7...D0 x x x x x x x x x: Don't care
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D7...D0: Data for special segment and control function
10) Set the following fields of the control and status register (CSR):
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NB_BITS_RD: 0
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NB_BITS_WR: 8 (decimal)
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INDEX: 01
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CS_CMD: 1
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START: 1
11) Wait for CSRB to go low, which indicates the CSR is ready to receive new
data. It is advised that you read the bit before and after every write access
to CSR to check the status.
12) Set the following fields of the control and status register (CSR):
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INDEX: 01
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CS_CMD: 0
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START: 0
The autotransmit mode is controlled by the setup 5 register (SR5). The follow-
ing example configures µWire for a read access on CS0 with serial clock out
inverted, CS autotoggle enabled, DMA request disabled, and interrupt
enabled:
1) SR5 = DMA_TX_EN: 0
IT_EN: 1
AUTO_TX_EN: 1
CS_TOGGLE_TX_EN: 1
2) SR1 = CS0_EDGE_RD: 0
CS0_EDGE_WR: 1
CS0CS_LVL: 0
CS0_FREQ: 00
CS0_CHK: 1
Note:
Data out is latched on falling edge of the serial clock. Data in is sampled on
rising edge.
MicroWire Interface
MPU Public Peripherals 7-43