MVME177 Functional Description

 

Table 4-1. EPROM and Flash Control and Configuration

 

 

 

 

 

 

Jumper or Control Bit

Control Condition

Memory ConÞguration

 

 

 

 

 

FLASHJP jumper J8

Jumper in (= low)

2MB EPROM (lower) and 2MB Flash

 

 

 

(upper)

 

 

 

 

 

 

Jumper out (= high)

All 4MB Flash

 

 

 

 

 

VMEchip2 bit GPIO2

GPIO2 bit low (and

First 2MB Flash accessible (Note)

 

 

with J8 jumper in)

 

 

 

 

 

 

 

 

GPIO2 bit high (and

Second 2MB Flash accessible (Note)

 

 

with J8 jumper in)

 

 

 

 

 

 

 

Note: These 2MB of Flash will be following the EPROMs in memory if the FLASHJP (J8) jumper is in, and could be read or write depending on the Flash write protect control.

Because only 1M x 8-bit Flash chips are used, there is no user- configured jumper selection block required to pick the Flash chip size.

The memory map for the Flash devices is controlled by the

VMEchip2 ASIC. The 32-bit wide Flash can support:

8 bit

16 bit, and

32 bit access

Flash write protection is programmable through the VMEchip2 GPIO register. The address map location of Flash is at $000000 through $3FFFFF at local reset if the FLASHJP jumper (J8) is in, providing for the all-Flash mode. In the mixed EPROM/Flash mode, half of the Flash is accessable at addresses $200000 through $3FFFFF, depending on the condition of the VMEchip2 GPIO2 bit.

Because the MVME177 uses 1M x 8-bit Flash memory devices and EPROMs with no download ROM, the software programs the VMEchip2 ROM0 and REV EROM bits properly so that the Flash/EPROM appears at address $0 after powerup. The hardware is implemented so that the EPROM/Flash appears at address $00000000 following a local bus reset.

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Motorola MVME177 Eprom and Flash Control and Configuration, Jumper or Control Bit Control Condition Memory ConÞguration