Chapter 1: Hardware Description

NOTE

Accesses from the CPM and the PowerSpan cannot go through the Memory Management Unit (MMU), unlike the core accesses. Therefore, the CPM and PowerSpan must use the physical addresses when accessing the SDRAMs (most significant bit = 0). Accesses to 0x8000 0000 will not address the SDRAMs.

Interrupts

The PCI bridge PowerSpan and the communication peripherals generate interrupt requests to the PowerQUICC II. These interrupts are level sensitive, active low.

Table 1-2. Local Interrupts

Source

MPC2860 Pin

MPC8260 IRQ

 

 

 

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Memory Controllers

The sophisticated memory controller units included in the PowerQUICC II are used on the 4538 boards to control all the external devices, except the PowerSpan, which is directly a 60x bus-compatible device. These units are a General Purpose Chip-select Machine (GPCM) for SRAM, FLASH, and peripherals control, three User Programmable Machines (UPM), and two SDRAM control machines (one used for Main SDRAM on 4538).

The memory controller unit to be used is defined bank per bank. Each bank is defined by its Base Register (BRx) and its Option Register (ORx). The memory machine selection is done in the Option register.

Table 1-3. PowerQUICC II Memory Controller Machine Usage

Element Accessed

Bank

Memory Controller

 

 

 

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4538 Hardware Reference Manual

7