PXD20RM Datasheet, PDF (594/1628 Pages) Freescale Semiconductor, Inc – PXD20 Microcontroller

Address: Base + 0x0014
Access: User write-only
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
R0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset 0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
16
R0
W
Reset 0
Field
CMD
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
CMD
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Figure 13-12. Compact Command Register (DRAMC_CCMD)
Table 13-11. DRAMC_CCMD field descriptions
Description
The compact command register gives the option to send commands to the DRAM using 16-bit writes.
See Table 13-12.
Table 13-12. DRAMC_CCMD register options
CMD[15:14]
Description
00
Write DRAM attributes and wait (wait time = wait time till next command) Wait is executed
after writing attributes.
• CKE = CMD[13]
• Self Ref En = CMD[12]
• CLK ON = CMD[11]
• CMD MODE = CMD[10]
• If (CMD[7] == 1’b1)
• Wait time = (CMD[6:0] × 512) dram clock periods
Or
• Wait time = (CMD[6:0] × 32) dram clock periods
01
DRAM command
• DRAM_CS = CMD[12]
• DRAM_RAS = CMD[11]
• DRAM_CAS = CMD[10]
• DRAM_WEB = CMD[9]
• DRAM_BA[2:0] = CMD[8:6]
• DRAM_ADDRESS[10] = CMD[5]
• if(CMD[4] == 1’b1) turn off CKE DRAM attribute bit¹
1x
DRAM set mode registers
• DRAM_CS = 0
• DRAM_RAS = 0
• DRAM_CAS = 0
• DRAM_WEB = 0
• DRAM_ADDRESS[13] = 0
• DRAM_BA[2] = 0
• DRAM_ADDRESS[12:0] = CMD[12:0]
• DRAM_ADDRESS[14:13] = CMD[14:13]
1 _{CKE is turned off the clock cycle when sending the requested command to the DRAM.}
13-14
PXD20 Microcontroller Reference Manual, Rev. 1
Preliminary—Subject to Change Without Notice
Freescale Semiconductor