ST7540 Datasheet, PDF (18/44 Pages) STMicroelectronics – FSK power line transceiver

Functional description
Table 8. ST7540 synthesized frequencies
--
600
1
75684 76335
0.5
75684 76335
1200
1
75358 76660
76
0.5
75358 76660
2400
1
74870 77148
0.5
74870 77148
4800
1
73568 78451
ST7540
--
600
1
132161 132813
0.5
132161 132813
1200
1
131836 133138
132.5
0.5
131836 133138
2400
1
131348 133626
0.5
131348 133626
4800
1
130046 134928
6.4
ST7540 Mains access
ST7540 can access the Mains in two different ways:
● Synchronous access
● Asynchronous access
The choice between the two types of access can be performed by means of Control
Register bit 14(see Table 12) and affects the ST7540 data flow in Transmission Mode as in
Reception Mode (for how to set the communication Mode, see Section 6.5).
In data transmission mode:
● Synchronous Mains access: on clock signal provided by ST7540 (CLR/T line) rising
edge, data transmission line (TxD line) value is read and sent to the FSK Modulator.
ST7540 manages the Transmission timing according to the BaudRate Selected.
● Asynchronous Mains access: data transmission line (TxD line) value enters directly to
the FSK Modulator. The Host Controller manages the Transmission timing (CLR/T line
should be neglected).
In data reception mode:
● Synchronous Mains access: on clock signal recovered by a PLL from ST7540 (CLR/T
line) rising edge, value on FSK Demodulator is read and put to the data reception line
(RxD line). ST7540 recovers the bit timing timing according to the BaudRate Selected.
● Asynchronous Mains access: Value on FSK Demodulator is sent directly to the data
reception line (RxD line). The Host Controller recovers the communication timing
(CLR/T line should be neglected).
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