ST7540TR STMicroelectronics, ST7540TR Datasheet - Page 19

• Manufacturer Part Number: ST7540TR
• Description: IC TXRX FSK POWER LINE 28-TSSOP
• Manufacturer: STMicroelectronics
• Type: Transceiverr

Specifications of ST7540TR

• Number Of Drivers/receivers: 1/1
• Voltage - Supply: 5 V ~ 9 V
• Mounting Type: Surface Mount
• Package / Case: 28-TSSOP Exposed Pad, 28-eTSSOP, 28-HTSSOP
• For Use With: 497-5485 - BOARD EVAL ST7540 PWR LINE TXRX
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Protocol: -
• Lead Free Status / Rohs Status: Compliant
• Other names: 497-5528-2

ST7540
6.5
Host processor interface
ST7540 exchanges data with the host processor through a serial interface.
The data transfer is managed by REG_DATA and RxTx Lines, while data are exchanged
using RxD, TxD and CLR/T lines.
Four are the ST7540 working modes:
●
●
●
●
REG_DATA and RxTx lines are level sensitive inputs.
Table 9. Data and Control register access bits configuration
ST7540 features two type of Host Communication Interfaces:
●
●
The selection can be done through the UART/SPI pin. If UART/SPI pin is forced to “0” SPI
interface is selected while if UART/SPI pin is forced to “1” UART interface is selected. The
type of interface affects the Data Reception by setting the idle state of RxD line. When
ST7540 is in Receiving mode (REG_DATA=”0” and RxTx =“1”) and no data are available on
mains (or RxD is forced to an idle state, i.e. with a conditioned Detection Method), the RxD
line is forced to “0” when UART/SPI pin is forced to ”0” or it is forced to “1” when UART/SPI
pin is forced to ”1”.
The UART interface allows to connect an UART compatible device while SPI interface
allows to connect an SPI compatible device. The allowed combinations of Host
Interface/ST7540 Mains Access are:
Table 10. Host interface / ST7540 mains access combinations
Data Transmission
Data Reception
Control Register Read
Control Register Write
UART
UART
SPI
SPI
interface type
Host device
Data Reception
Data Transmission
Control Register Read
Control Register Write
SPI
UART
“1”
“1”
“0”
“0”
UART/SPI pin
REG_DATA
Transmission
Reception
Transmission
Reception
Communication
0
0
1
1
mode
Asynchronous
X
X
Functional description
Mains access
RxTx
1
1
0
0
Synchronous
X
X
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