Memory and PCMCIA Control Module

Table 10-1.

SA-1100 Transactions

 

 

 

 

 

 

 

 

 

 

 

 

Burst

Starting

Description

 

Bus Operation

 

Address

 

 

 

Size

 

 

 

 

Bits <4:2>

 

 

 

 

 

 

 

 

 

 

 

 

 

Read single

1

 

Any

Generated by core, DMA, or read buffer request.

 

 

 

 

 

 

 

Read burst

4

 

0

Generated by read buffer or DMA request.

 

 

 

 

4

 

 

 

 

 

 

 

 

Read burst

8

 

0

Generated by cacheline fills or read buffer request.

 

 

 

 

 

 

 

Write single

1

 

Any

1..4 bytes are written as specified by the byte mask.

 

 

 

 

 

Generated by write buffer or DMA request.

 

 

 

 

 

 

 

Write burst

2

 

0, 1, 2

All 4 bytes of each word are written. Generated by

 

 

 

 

4, 5, 6

write buffer or DMA request.

 

 

 

 

 

 

 

 

 

 

 

 

Write burst

3

 

0, 1

All 4 bytes of each word are written. Generated by

 

 

 

 

4, 5

write buffer or DMA request.

 

 

 

 

 

 

 

 

 

 

 

 

Write burst

4

 

0

All 4 bytes of each word are written. Generated by

 

 

 

 

4

write buffer or DMA request.

 

 

 

 

 

 

 

 

 

 

 

 

Write burst

8

 

0

Cacheline copyback. All 32 bytes are written.

 

 

 

 

 

Generated by write buffer.

 

 

 

 

 

 

10.1.6Read-Lock-Write

The read-lock-write sequence is generated by an SWP instruction to a noncacheable/nonbufferable location. Locked access to memory is ensured through internal arbitration of accesses to the memory controller.

10.1.7Aborts and Nonexistent Memory

Reads from reserved address locations (as specified in the memory map) will result in a data abort exception. Writes to reserved address space will have no effect.

Reads and writes from or to nonexistent memory are not detected in hardware. In case no memory is selected on a read, the value last driven on the data bus is returned.

A single access to a disabled DRAM bank (MDCNFG:DEx=0) will cause a CBR refresh cycle to all banks. Zeros are returned to the register file on reads and writes are dropped. A burst read access to a disabled DRAM bank will result in a data abort exception.

SA-1100 Developer’s Manual

10-5

Page 119
Image 119
Intel manual Read-Lock-Write, Aborts and Nonexistent Memory, SA-1100 Transactions, Bus Operation, Bits