M48A Datasheet, PDF (1/9 Pages) Radiometrix Ltd – M48A modem chip - for narrow band wireless data link

Hartcran House, 231 Kenton Lane, Harrow, Middlesex, HA3 8RP, England
Tel: [phone], Fax: [phone], www.radiometrix.com
M48A MODEM
PRELIMINARY
07 September 2009
M48A modem chip – for narrow band wireless data link
The M48A is a half-duplex serial modem
controller suitable for use with narrow band
receivers, transmitters and transceivers. It
supports a maximum transparent data
throughput of 4800baud while baseband
modulation frequencies do not exceed 3.2KHz.
The device supports (programmable) long
startup/preamble durations sometimes
required for synthesized narrow band devices.
Figure 1: M48A-000-DIL modem IC
The M48 provides a half duplex link, but provided no two devices attempt to transmit at one time (a 'low' on
RX_flow may be used as a primitive 'CTS' indication) no further restrictions on data transmission need be
made, as all transmit timing, valid data identification and data stream buffering is conducted by the device.
This unit supports a range of user interface data rates, in asynchronous data format: 1 start bit, 8 data bits, 1
stop bit. The supplied default (and the maximum transparent throughput) is 4800 baud
To connect to a true RS232 device, inverting level shifters must be used (MAX232 type are ideal, but simple
NPN transistor switches often suffice). With typical microcontrollers and uarts, direct connection is usable.
Note that TXD has no internal pullup.
Features
! Operating voltage (temperature):
5V for standard version (-40°C to +85°C)
! Maximum usage of the range capability of an RF module
! Compatible with fast or slow transmitter power up timing requirements
! 5kbps pulse duration coded protocol
! Synchronisation codes and checksum to reduce false triggering on noise
! Programmable transmit address and four receive addresses
! Programmable timing parameters (preamble length, etc)
! Programmable auxiliary serial output (to program radio modules)
! Programmable serial modem baud rate (1200 - 76800 bps, half-duplex)
! Suitable to be used with Narrow Band FM radio modules
! Addressable point-to-point and point to multi point
! Packet acknowledge/resend (ACK) mode
! Store and forward repeater function
Applications
! PDAs, organisers & laptops
! Handheld / portable terminals
! Remote operated vehicles
! Data loggers
! In-building environmental monitoring and control
! Industrial (SCADA) telemetry and M2M systems
! Fleet management, vehicle data acquisition
Radiometrix Ltd
M48A Modem Data Sheet
page 1