Motorola MSC8101 ADS User's Guide download pdf (Page 62)

2-10 MSC8101 User’s Guide

Reset Configuration and Boot

The configuration master first reads a value from address 0x00 and then reads a value

from addresses 0x08, 0x10, and 0x18. These four bytes form the configuration word of the

configuration master, which then proceeds reading the bytes that form the configuration

word of the first slave device. The configuration master drives the whole configuration

word on

D[0–31] and toggles its A0 address line. Each configuration slave uses its RSTCONF

input as a strobe for latching the hard reset configuration word during

HRESET assertion

time. Thus, the first configuration slave whose

RSTCONF input connects to the

configuration master’s

A0 output latches the word driven on D[0–31] as its configuration

word. The configuration master continues to configure all MSC8101 devices in the

system. The configuration master always reads eight configuration words, regardless of

the number of MSC8101 devices in the system.

2.3.2 Reset Configuration Word Values

In the system described in Figure 2-4, one arbiter handles the system bus arbitration and

one memory controller controls the signals and attributes of all memory accesses. Any

MSC8101 in the system can handle the roles of system arbiter and memory controller. The

MSC8101 that serves as a system arbiter uses its internal arbiter, and the rest of the

MSC8101s are configured to work in an external arbitration mode. The MSC8101 that

serves as the memory controller for the system uses its memory controller, and the

remaining MSC8101s are configured to work with an external memory controller. The

arbitration mode and memory controller mode are set in the hard reset configuration word.

Each MSC8101 in the system must have a unique value in the IMMR. In the reset

configuration word, there can be up to eight different values for the first three bits of the

IMMR (ISB[0–2]). Each MSC8101 in the system must be configured to one of these

values. These values can be changed during boot.

MODCK is also configured in reset

configuration to choose the desired clock frequency.

Table 2-6. Configuration EPROM Addresses

Configured Device Byte 0 Address Byte 1 Address Byte 2 Address Byte 3 Address

Configuration master 0x00 0x08 0x10 0x18

First configuration slave 0x20 0x28 0x30 0x38

Second configuration slave 0x40 0x48 0x50 0x58

Third configuration slave 0x60 0x68 0x70 0x78

Fourth configuration slave 0x80 0x88 0x90 0x98

Fifth configuration slave 0xA0 0xA8 0xB0 0xB8

Sixth configuration slave 0xC0 0xC8 0xD0 0xD8

Seventh configuration slave 0xE0 0xE8 0xF0 0xF8

1 2 ... 57 58 59 60 61 62 63 64 65 66 67 ... 345 346

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Motorola MSC8101 ADS User's Guide Page 62