Computer Hardware User's Guide

Memory Interface Control Registers
9-7 TMS320C30 and TMS320C31 External-Memory Interface
9.3 Memory Interface Control Registers
Two memory interface control registers, the primary-bus control register and
the expansion-bus control register, are described in this section.
9.3.1 Primary-Bus Control Register
The primary bus control register is a 32-bit register that contains the control bits
for the primary bus (see Figure 9–2). Table 9–3 describes the register bits with
the bit names and functions.
Figure 9–2. Primary-Bus Control Register
21 0
SWWWTCNTBNKCMPxxxx
345678910111215–1331–16
HOLDSTNOHOLDHIZ
R/W
R/W R/W R
R/WR/W
Notes: 1) xx = reserved bit, read as 0
2) R = read, W = write
Note:
After changing the bit fields of the primary-bus control register, up to three
instructions are fetched before the primary bus is reconfigured because the
configuration change is performed in the execute stage of the pipeline.