Baseband Block Introduction

This document specifies the BB section of the GX8 RF/system module for RPE-1 Transceiver Card The BB section of the GX8 employs the MAD2 ASIC from DCT-3, RFI2 (RF/BB interface ASIC) from DCT-2, and a new ASIC named as SMART to interface to a PCMCIA slot, and to a GSM phase I SIM reader. The main guideline for the baseband block is the PC Card '95 release, which contains considerable hardware and software enhancements compared to the earlier versions of the PCMCIA standard. Another important set of proposals is included in the ExCA specification that provides a more narrow definition of PC Card technology for PC architecture machines. The current revision of the ExCA standard is Release 1.50 .

Modes of Operation

The Baseband in RPE-1 operates in one of the several operating modes. All modes except one are normal PCMCIA modes. One mode is for use in nonPCMCIA environments. The diagram below presents both physical operating and logical sub operating modes.

RPE-1 can be used in systems where standard PCMCIA host controller is not available. In non-PCMCIA mode the PCMCIA interface is bypassed inside the interface ASIC so that the MBUS, FBUS and PCM speech data signals are brought directly to the PCMCIA connector.

Operating modes and interface signals of the RPE-1






-FBUS (to DAI box) -PCM speech


-FBUS -PCM speech


-Flow control signals

System Module Technical Documentation

Normal operation mode

In the normal operating mode the RPE-1 acts as a cellular telephone without built-in UI. After power-up the PCMCIA interface is first in memory mode, during which the host computer reads the PC CARD standard CIS information from the RPE-1 card. The CIS is stored in the internal ROM of the SMART interface ASIC. After reading the CIS the interface goes into I/O mode for runtime operation. One bit in the SMART operation control register determines which mode is being used.

In normal operation the card looks like a modem card to the host computer. The operation interface emulates a 16C550 UART. Control data for the RPE -1 goes through the UART to the internal FBUS of system ASIC MAD2. In addition there is an USRT through which speech data flows. It has its own control and data registers in the interface ASIC. All this is implemented in the SMART ASIC.

Flash programming mode

The Flash programming mode is used in updating the card software. The host computer and the RPE-1 control software in it control the Flash download procedure.

During Flash programming the FBUS operates in synchronous mode with the MBUS signal acting as a clock. The data to be downloaded to the RPE-1 goes through the FBUS. The SMART ASIC generates the clock. The Flash mode is selected with a bit in SMART operation mode control register.

Non-PCMCIA mode

RPE-1 can be used in applications where standard PCMCIA interface is not available. Non-PCMCIA mode offers a simple interface for controlling it. The controller thus does not have to be a personal computer but a simple microcontroller is enough.

Non-PCMCIA mode is activated by connecting pin "BVD2/SPKR#" to the ground on the host side of the PCMCIA connector. When this signal is 0 the interface ASIC enters the non-PCMCIA mode and routes FBUS, flow control signals and PCM speech data bus directly to the PCMCIA connector. Also A8 should be pulled down with 100k resistor to enable SMART ASIC sleep clock feature. Internal registers of the interface ASIC are not accessible, so the ASIC takes care of proper startup of the card. The external system must give a proper RESET signal.

In the non-PCMCIA mode MBUS is routed via a bidirectional switch directly to the PCMCIA connector pin 29 A0. This switch is controlled by BVD2/SPKR#. This allows user to control MAD2 with MBUS.

Technical Documentation System Module

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