COBHAM GR740 User Manual

GR740-UM-DS, Nov 2017, Version 1.7 103 www.cobham.com/gaisler
GR740
10.4.9 Address bus connection
The SDRAM address bus should be connected to mem_addr[12:0], the bank address to mem_ba[1:0],
and the data bus to mem_dq[63:0] or mem_dq[31:0] if a 32-bit SDRAM data bus is used. Checkbits
should be tied to mem_dq[95:64] in full-width mode and mem_dq[79:64] in half-width mode.
10.4.10 Command sequences
Below illustrates the sequences of commands issued by the SDRAM controller for read and write
bursts at the minimum delay settings. CS and DQM in the table refers to the CS and DQM belonging
to the selected address and size, unused banks and byte lanes are kept at 1 throughout the access.
Note: * Dummy read while waiting for end of data, data not used
Table 87. Length-4 read access command sequence
Cycle 2T signaling disabled 2T signaling enabled
CSn CMD DQM BA Addr CSn CMD DQM BA Addr
- 1 (NOP) (1) - - 1 (NOP) 1 - -
0 0 RAS (1) Bank Row 1 (RAS) 1 (Bank) (Row)
1 0 NOP 1 (Bank) (Row) 0 RAS 1 Bank Row
2 0 READ 0 Bank Col 1 (READ) 1 (Bank) (Col)
3 0 READ 0 Bank Col+1 0 READ 0 Bank Col
4 0 READ 0 Bank Col+2 1 (READ) 0 (Bank) (Col+2)
5 0 READ 0 Bank Col+3 0 READ 0 Bank Col+2
6 0 READ* 0 Bank Col+4 1 (READ) 0 (Bank) (Col+4)
7 0 READ* 0 Bank Col+5 0 READ* 0 Bank Col+4
8 0 READ* 0 Bank Col+6 1 (READ) 0 (Bank) Col+6
9 0 PCH 1 Bank (Col+6) 0 READ* 0 Bank Col+6
10 1 (NOP) 1 (Bank) (Col+6) 1 (PCH) 1 (Bank) (Col+8)
11 1 (NOP) 1 (Bank) (Col+6) 0 PCH 1 Bank (Col+8)
12 ... 1 (NOP) 1 (Bank) (Col+6) 1 NOP 1 (Bank) (Col+8)
Table 88. Length-4 write access command sequence
Cycle 2T signaling disabled 2T signaling enabled
CSn CMD DQM BA Addr CSn CMD DQM BA Addr
- 1 (NOP) 1 - - 1 (NOP) 1 - -
0 0 RAS 1 Bank Row 1 (RAS) 1 Bank (Row)
1 0 NOP 1 (Bank) (Row) 0 RAS 1 Bank Row
2 0 WRITE 0 Bank Col 1 (WRITE) 1 Bank (Col)
3 0 WRITE 0 Bank Col+1 0 WRITE 0 Bank Col
4 0 WRITE 0 Bank Col+2 1 (WRITE) 0 Bank (Col+2)
5 0 WRITE 0 Bank Col+3 0 WRITE 0 Bank Col+2
6 0 WRITE 1 Bank Col+4 1 (WRITE) 0 Bank (Col+4)
7 0 PCH 1 Bank Col+5 1 (PCH) 1 Bank (Col+4)
8 1 NOP 1 (Bank) Col+6 0 PCH 1 Bank Col+6
9 1 NOP 1 (Bank) (Col+6) 1 NOP 1 Bank Col+6

COBHAM GR740 Specifications

General

Brand	COBHAM
Model	GR740
Category	Computer Hardware
Language	English