Datasheet

891
32142D–06/2013
ATUC64/128/256L3/4U
1. The size of the data field: 7 (size and starting address + read length indicator) in the
length field.
2. The size of the transfer: Words, halfwords, or bytes.
3. The starting address of the transfer.
4. The number of
bytes to read (max 65532).
The 4 MSB of the 36 bit SAB address are submitted together with the size field (2 bits). The 4
remaining address bytes are submitted before the number of bytes to read. The size of the
transfer is specified using the values from the following table:
Below is an example read command:
1. 0x55 (sync)
2. 0x81 (command)
3. 0x00 (length MSB)
4. 0x07 (length LSB)
5. 0x25 (size and address MSB, the two MSB of this byte are unused and set to zero)
6. 0x00
7. 0x00
8. 0x00
9. 0x04 (address LSB)
10. 0x00
11. 0x04
12. 0xXX (CRC MSB)
13. 0xXX (CRC LSB)
The length field is set to 0x0007 because there are 7 bytes of additional data: 5 bytes of address
and size and 2 bytes with the number of bytes to read. The address and size field indicates one
word (four bytes) should be read from address 0x500000004.
Table 34-43. Size Field Decoding
Size field Description
00 Byte transfer
01 Halfword transfer
10 Word transfer
11 Reserved
Table 34-44. MEMORY_READ Details
Command Details
Command value 0x81
Additional data Size, Address and Length
Possible responses
0xC1: MEMDATA (Section 34.6.8.4)
0xC2: MEMORY_READWRITE_STATUS (Section 34.6.8.5)
0x41: NACK (Section 34.6.8.2)