4

IP2 Chip

Programming Model

This section defines the programming model for the control and status registers (CSRs) in the IP2 chip. The base address of the CSRs is hardwired to $FFFBC000.

The possible operations for each bit in the CSR are as follows:

RThis bit is a read-only status bit.

R/W

This bit is readable and writable.

R/C

This status bit is cleared by writing a one to it.

CWriting a zero to this bit clears this bit or another bit. This bit reads as zero.

SWriting a one to this bit sets this bit or another bit. This bit reads as zero.

The possible states of the bits after assertion of the RESET* pin (powerup reset or any local reset) are as defined below.

RThe bit is affected by reset.

XThe bit is not affected by reset.

A summary of the IP2 chip CSR registers is shown in Table 4-3. The CSR registers can be accessed as bytes, words, or longwords. They should not be accessed as lines. They are shown in the table as bytes, and the bits in most of the following register descriptions are labeled as bits 7 through 0.

4-10

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Motorola MVME172 manual This bit is readable and writable, This status bit is cleared by writing a one to it