Preliminary Technical Information

AD6426

This Information applies to a product under development. Its characteristics and specifications are subject to change without notice. Analog Devices assumes no

obligation regarding future manufacture unless otherwise agreed to in writing. No responsibility is assumed by Analog Devices for its use; nor for any

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Revision Preliminary 2.3 (June 9, ´98)

- 16 -

Confidential Information

Wait

The H8 microprocessor WAIT input signal can be controlled

externally by programming the FLASHPWD pin to switch to

the WAIT input function. Setting the flag FLASHPWD Disable

in CC Control Register 77 to 1 and GPO11 Select to 0,

transforms the FLASHPWD output pin into a WAIT input pin.

External devices driving WAIT must drive high on reset and

until the software has changed the FLASHPWD pin to the

WAIT function.

Automatic Booting

To allow download of FLASH memory code into the final

system, the AD6426 provides a small dedicated routine to

transfer code through the Data Interface into the FLASH

memory. This routine is activated by asserting the

BOOTCODE pin.

Power Control

The AD6426 and Layer 1 software is optimized to minimize

the mobile radio power consumption in all modes of operation.

Two power control registers are dedicated for activating and

deactivating functional modules:

Bit

POWER CONTROL INTERNAL CC Control

Register 44

2

Synthesizer Interface Power Enable

1

DSP Interface Power Enable

0

Encryption Power Enable

Bit

POWER CONTROL EXTERNAL CC Control

Register 45

5

Output Clock Enable (will reset to 1)

4

General Purpose Power Control

2

DSP Power Control

1

Radio Power Control

INTERFACES

The GSM Processor provides eleven external interfaces for

dedicated purposes:

1.

Memory Interface

2.

EEPROM Interface

3.

SIM Interface

4.

Accessory Interface

5.

Universal System Connector Interface

6.

Keypad / Backlight / Display Interface

7.

Battery ID Interface

8.

Voiceband/Baseband Converter (EVBC)

Interface

9.

Radio Interface

10. Test Interface

11. Debug Interface

Memory Interface

The memory interface of the AD6426 serves two purposes.

Primarily, it provides the data, address, and control lines for

the external memories (RAM and ROM / FLASH Memory).

Secondly, the data and address lines are used to interface with

the display. The pins of the memory interface are listed in

Table 5.

Table 5. Memory Interface

Name

I/O

Function

ADD20 : 0

O

Address bus

DATA15:0

I/O

Data bus

RD

O

Read strobe

HWR

O

High write strobe / Upper

Byte Strobe

LWR

O

Low write strobe / Lower

Byte Strobe

WR

O

Write Strobe

RAMCS

O

RAM chip select

ROMCS

O

FLASH / ROM chip select

FLASHPWD

O

FLASH Powerdown

The HWR and LWR pins can be configured to function as

UBS and LBS, respectively, by setting the SRAM16 bit (bit 0)

of the MEMIF H8 Peripheral Control Register 80. This bit is

reset at power-up. When configured as UBS and LBS, these

pins facilitate access of 16-bit SRAM in conjunction with the

Read/Write Strobes.

The pin FLASHPWD is automatically asserted low when the

H8 enters the Software Standby Mode, and de-asserted when

an interrupt causes the H8 to exit the Software Standby Mode.

This allows the use of “deep power down mode” for certain

FLASH memories. Also the entire data bus is driven low

during software standby mode.

EEPROM Interface

The AD6426 provides a 3-wire interface to an external

EEPROM by using three GPIOs of the control processor.

Table 6 shows the functionality of these three pins.

Table 6. EEPROM Interface

Name

I/O

Function

EEPROMDATA

I/O

EEPROM data

EEPROMCLK

O

EEPROM clock

EEPROMEN

O

EEPROM enable