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Intel® PXA255 Processor Developer’s Manual 6-47
Memory Controller
2:0 R/W RTx<2:0>
ROM type
000 - Nonburst ROM or Flash Memory
001 - SRAM
010 - Burst-of-four ROM or Flash (with non-burst writes)
011 - Burst-of-eight ROM or Flash (with non-burst writes)
100 - Variable Latency I/O (VLIO)
101 - reserved
110 - reserved
111 - reserved
Burst refers to the device’s timing. When the subsequent reads from the
device take less time than the first read from a device, it is referred to as
burst timing. The address bits must also be taken into account for burst
timing devices. For example, in a burst-of-four device, only the lower two
non-byte address bits can change for burst timing. For 32-bit devices, this is
MA[3:2]. The address order can go 00, 01, 10, 11 where the reads from 01,
10, and 11, take less time to come out of the device. For burst-of-eight
devices, the lower three non-byte address bits can change. Writes to these
devices are non-burst.
Table 6-21. MSC0/1/2 Bit Definitions (Sheet 3 of 3)
0x4800_0008
0x4800_000C
0x4800_0010
MSC0
MSC1
MSC2
Memory Controller
Bit
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
RBUFF1/3/5
RRR1/3/5 RDN1/3/5 RDF1/3/5
RBW1/3/5
RT1/3/5
RBUFF0/2/4
RRR0/2/4
RDN0/2/4 RDF0/2/4
RBW0/2/4
RT0/2/4
Reset
0 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 * 0 0 0
Bits Access Name Description