SLAU723A October 2017 – October 2018 MSP432E401Y , MSP432E411Y
1-Wire Data Write (ONEWIREDATW), offset 0x008
The 1-Wire Data Write (ONEWIREDATW) and 1-Wire Data Read (ONEWIREDATR) registers are used to transmit or receive data. Data is processed LSB first, which means the lowest (and possibly only) byte is transferred first. Note that for normal processor use of writing and write/read, the ONEWIREDATW register must be written before the OP field of the ONEWIRECS register is programmed. If reading (or write/read), the ONEWIREDATR register is read after completion (when OP returns to value 0). When doing write/read ( OP =0x3), either register can be written. Because bits written as a 1 in the ONEWIREDATR register also act as a read, writing 0xFF is the same as a read of two bytes. Writing 0xF0 allows writing 0 for the lower nibble and reading the upper nibble. If the slave does not know it is a read, each written 1 reads back as 1.
ONEWIREDATW is shown in Figure 22-9 and described in Table 22-7.
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| 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| B3 | B2 | B1 | B0 | ||||||||||||||||||||||||||||
| R/W-0x0 | R/W-0x0 | R/W-0x0 | R/W-0x0 | ||||||||||||||||||||||||||||