JAJSGM3 December 2018 DAC8742H
PRODUCTION DATA.
This register controls various modem features including: FF/PA Manchester data polarity, number of FF/PA preamble bits, analog output amplitude, modem enable, duplex mode, and request to send.
MODEM_CONTROL is shown in Figure 27 and described in Table 8.
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15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 |
FFPA_POL | FFPA_PREAMBLE | RESERVED | TX_AMP | ||||
R/W | R/W | R | R/W | ||||
7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
TX_AMP | MOD_EN | DUP_EN | RESERVED | RTS | |||
R/W | R/W | R/W | R | R/W | |||
Bit | Field | Type | Reset | Description |
---|---|---|---|---|
15 | FFPA_POL | R/W | 0 | Sets the transmitted polarity of the Manchester encoded data
0 = Logical 1 is transmitted as a transition from high-to-low (default) 1 = Logical 1 is transmitted as a transition from low-to-high |
14-12 | FFPA_PREAMBLE | R/W | 0 | Number of preamble bytes sent is the value programmed in this register plus 1 |
11-9 | RESERVED | R | 0 | Reserved |
8-4 | TX_AMP | R/W | 00100 | Unsigned binary value that controls the amplitude (HART mode only) of the transmitted waveform in 25mVpp steps. Default value 00100 for 500mVpp output amplitude. Amplitude may vary from 400mVpp to 800mVpp. |
3 | MOD_EN | R/W | 1 | 0 = Disables TX/RX of the modem
1 = Enables TX/RX of the modem (default) |
2 | DUP_EN | R/W | 0 | 0 – TX FIFO is not connected to RX FIFO (default)
1 = Connects TX FIFO to RX FIFO |
1 | RESERVED | R | 0 | Reserved |
0 | RTS | R/W | 0 | 0 = No active request to send in HART mode (default)
1 = Active request to send in HART mode |