JAJSE97D June 2017 – May 2019 DAC8740H , DAC8741H
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 13.
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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 25-mVPP steps. Default value 00100 for 500-mVPP output amplitude. Amplitude may vary from 400 mVPP to 800 mVPP. |
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 |