Figure 4.5-1.Controller Memory Interface - Motorola ASTRO XTS 2500 Service Manual

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900 MHz Detailed Theories of Operation: VOCON Functional Blocks

The RESET_OUT of the Patriot IC (U800) is at the GPIO voltage logic level (see section 4.5.6.1.1.).

Components CR800 and R812 are used to convert the voltage down to a 1.8-volt logic level, and this

1.8 volt reset signal is fed to the Flash RESET pin. When this pin is asserted (active low logic), the

Flash is in reset mode. In this mode, the internal circuitry powers down and the outputs become high

impedance connections.

The Flash active low chip select pin, EN_CE, is connected to the active low CS0 pin (TP_CS0 test

point) of the EIM. When the EN_CE is not asserted, the Flash is in standby mode which reduces the

current consumption.

Several other active low controls pins determine what mode the Flash memory is in:

• the address valid pin ADV which is connected to the EIM LBA signal

• the output enable pin EN_OE that is connected to the EIM OE signal, and

• the write enable pin EN_WE which connected to the EIM EB1 signal.

For read mode, the ADV and EN_OE pins would be asserted while the EN_WE pin would not be

asserted. When the EN_WE is asserted and the EN_OE pin is non-asserted, the Flash would

operate in the write mode.

6816985H01-B

Figure 4.5-1. Controller Memory Interface

August 16, 2007

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