ST7540TR STMicroelectronics, ST7540TR Datasheet - Page 20

• 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

Functional description
6.5.1
20/44
Figure 6.
ST7540 allows to interface the Host Controller using a five line interface (RxD,TxD,RxTx,
CLR/T, & REG_DATA) in case of Synchronous mains access or using a 3 line interface
(RxD,TxD & RxTx) in Asynchronous mains access. Since Control Register is not accessible
in Asynchronous mode, in this case REG_DATA pin must be tied to GND.
Communication between Host and ST7540
The Host can achieve the Mains access by selecting REG_DATA=”0” and the choice
between Data Transmission or Data Reception is performed by selecting RxTx line (if RxTx
=“1” ST7540 receives data from mains, if RxTx=”0” ST7540 transmits data over the mains).
Communication between Host and ST7540 is different in Asynchronous and Synchronous
mode:
●
Asynchronous mode:
In Asynchronous Mode, data are exchanged without any data Clock reference. The
host controller has to recover the clock reference in receiving Mode and control the Bit
time in transmission mode.
If RxTx line is set to “1” & REG_DATA=”0” (Data Reception), ST7540 enters in an Idle
State. After Tcc time the modem starts providing received data on RxD line.
If RxTx line is set to “0” & REG_DATA=”0” (Data Transmission), ST7540 enters in an
Idle State and transmission circuitry is switched on. After Tcc time the modem starts
transmitting data present on TxD line.
Host Controller
Synchronous and Asynchronous ST7540/Host Controller interfaces
UART/Asynchronous
Data Interface
ST7540
RxD
TxD
RxTx
CLR/T
REG_DATA
Host Controller
SPI/Synchronous
Data Interface
D03IN1415
ST7540
RxD
TxD
RxTx
CLR/T
REG_DATA
ST7540