Sierra Semiconductor Corp, San Jose has come up with a new analogue system on a chip, the SC11370 NMT/PMR, for mobile telephones and radios; and its first digital offerings the SC14400 and SC14401 for handsets and base stations. The company also has a single-chip Super VGA graphics offering for personal computers and is offering free software links to its SC11390 NMT/PMR ‘PABX on a chip’. Integrating the circuitry in devices helps reduce size, weight and power consumption – which is particularly important for portable devices. The new SC11370 analogue processor for cellular telephone and mobile radio applications integrates audio filtering; Dual Tone Multiple Frequency transmission and reception; and control tone filtering and Fast Frequency Shift Keying data modem functions all in a 44 PQFP. The device is compliant with the Nordic Mobile Telephone protocol, which operates across Northern Europe, and the closed loop PMR protocol for the mobile radio systems used in lorries and vans. Each functional block within the chip is partitioned to help control power usage. It also includes a microphone amplifier and earpiece driver and can be connected to an external microphone and high power speaker for ‘hands-free’ applications. Signal levels can be controlled through an I2C interface. The chip is available now, priced $20 for 1000 up. Sierra expects it to fare well – for the short term at least because of the remaining mileage left in the analogue market but is nevertheless preparing for a boom in digital communications which it predicts will happen in 1996. And so it has come up with the SC14400 Digital European Cordless Telecoms standard terminal processor and SC14401 analogue front end provide audio processing, ADPCM compression and burst mode control for handsets and base stations.
Base stations
Both have been designed using 3V CMOS technology to reduce the power needed in the handset, and are divided internally into sections that function only when needed. The SC14400 can handle four simultaneous conversations, with seamless switch-over between base stations, and provides advanced PABX facilities like call holding. It enables voice and user data – such as billing signals – to be accessed across eight programmable outputs. A microprocessor port provides access. It can also be programmed to control the system’s burst and frame timing, so bypassing the microprocessor. Two of the output pins have a 12mA capacity for driving PIN diode switches. An ADC is included on chip for automatic Received Signal Strength Indication; the ADC value can be read throught the microprocessor port. The chip can also control a radio frequency front end, including those with National Semiconductor Corp’s ARil interface. It comes in an 80-pin QFP package and will be available around the middle of February for below $10 in volume. The SC14401 is a 20-pin SOIC; its cost has not been fixed. For personal computer and board makers, Sierra has a new Super VGA Windows Integrated Fast Technology, or Swift, for Windows-based computers integrates a Super VGA graphics controller, HiColor-24 palette, dual clock generator and graphics accelerator.
By Lynn Stratton
When combined with a Video RAM or Dynamic oRAM display, the company says, Swift serves as a graphics adaptor capable of 80MHz video rates. It can also support Super VGA in motherboards and add-in graphics boards, from 640 by 480 to 1,024 by 768 with up to 16.8m colours. It handles all input-output, memory and video control communications to and from the host processor, VRAM or DRAM frame buffer and output to the colour palette and display. The subsystem supports all VGA modes and can use an unmodified VGA BIOS RAM. The graphics accelerater performs line-drawing, screen-to-screen bit block-transfer and block copy operations which can boost the speed of some Windows functions by between between four to ten times when compared with non-accelerated applications. Swift design includes a dual programmable clock generator on-chip. This creates all of the high-speed clock signals for the colour palette
, graphics controller and graphics coprocessor. Frequencies between 25MHz and 80MHz can be generated depending on the VGA mode selected. Clock programmability is useful, Sierra says, for tailoring Swift to specific cost and performance targets. It can be used either to match the display memory bandwidth to the colour palette bandwidth to get the best system performance – or can be optimised for cheaper and slower memory devices when peak performance is not needed. A development kit is provided with the chip set, containing device numbers SC15010 and SC15012. The two are housed in 160-pin PQFP packages. The SC1510 takes DRAM; the SC15012 supports VRAM display memory. They cost between $30 for the SC15010 and $40 for the SC15012 for 10,000-up. For those wanting to convert PABX functions for personal computers, Sierra is now providing free software that connects Windows-based personal computers to boards containing its SC11390 ‘PABX on a chip’. The application, called Phone Home, gives users a visual representation of the PABX demo board and enables users to call up and control PABX functions by simply moving or clicking an icon. To transfer a call for example, users need simply to drag their icons to the icon with which they want to connect; to set up a conference they need to drag additional callers to their icon.
Screen menus
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Screen menus also enable the user to set up the PABX such as which extensions faxes are sent to. The source code for the application, written in Microsoft’s Visual Basic is available as an example of how to interface to the SC11930. A packaged application program will also be available for licensing soon for those SC11390 PABX manufacturers not wishing to write their own version. Meantime, Sierra has also reported an early success for another personal computer product – the 5V ST4743XCTT voice-data-fax modem which is being used by New Media Corp in the US in PCMCIA I cards. The device, which Sierra says is ideal for notebook and palmtop computers, combines a controller, DSP and fax and data modem analogue processor in a TQFP package. It is a full-featured Class 2 fax modem that can transmit and receive at 9600bps. It supports Bell 103/212A, CCITT V.21, V22, V.22bis, V.23, V.27ter and V29 standards with error correction and data compression supported through MNP2-5, V.42 and V.42bis standards. It has an accompanying FastTrack developers kit and has been shipping since December for $24 per 10,000 up. Sierra says it also has the industry’s cheapest send-receive fax modem chipset. It can send a fax at 9600bps and receive at 4800bps. Transmission rate is 2400bps with available data compression up to 9600bps. It supports the Bell 103/212A, CCITT V.21, V.22, V.22bis, V.23, V27ter and V.29 standards with the choice of software or hardware MNP and V.42bis error correction and data compression. The company expects modems based on the low-cost-fax to retail for less than $50, and is hoping that a large proportion of customers for its existing Sendfax modem products will convert to its new technology and is offering full chip set documentation, modem solution schematics, demo boards and source codes to developers by way of encouragement. The modem comes in a PLCC and PQFP package and costs $13 for 10,000 up.
