SMC Networks PL241, AHB SRAM/NOR manual SMC Direct Command Register at

Models: AHB SRAM/NOR PL241

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3.3.5SMC Direct Command Register at 0x1010

Programmer’s Model

3.3.5SMC Direct Command Register at 0x1010

The write-only smc_direct_cmd Register passes commands to the external memory, and controls the updating of the chip configuration registers with values held in the set_opmode and set_cycles registers.

This register cannot be written to in either the Reset or Low-power state. Figure 3-10shows the register bit assignments.



 

    



 

8QGHILQHG

 

$GGU

Manual background VHWBFUH

FPGBW\SH

FKLSBVHOHFW

 

 

 

Figure 3-10 smc_direct_cmd Register bit assignments

 

 

 

Table 3-6lists the register bit assignments.

 

 

 

Table 3-6 smc_direct_cmd Register bit assignments

 

 

 

 

Bits

Name

Function

 

 

 

 

[31:26]

-

Reserved, undefined. Write as zero.

 

 

 

 

[25:23]

chip_select

Selects chip configuration register bank to update and enables chip mode register access depending

 

 

 

on cmd_type. The encoding is:

 

 

 

b000-b011 = chip selects 1-4 on interface 0

 

 

 

b100-b111 = reserved.

 

 

 

 

[22:21]

cmd_type

Determines the current command. The encoding is:

 

 

 

b00 = UpdateRegs and AHB command

 

 

 

b01 = ModeReg access

 

 

 

b10 = UpdateRegs

 

 

 

b11 = ModeReg and UpdateRegs.

 

 

 

 

[20]

set_cre

Maps to configuration register enable, smc_cre, output, when a ModeReg command is issued. The

 

 

 

encoding is:

 

 

 

b0 = smc_cre is LOW

 

 

 

b1 = smc_cre is HIGH when ModeReg write occurs.

 

 

 

 

[19:0]

addr

Bits mapped to external memory address bits [19:0] when command is ModeReg access.

 

 

 

Addr[19:16] are undefined.

 

 

 

Addr[15:0] matches wdata[15:0] when the commands are UpdateRegs and AHB command access.

 

 

 

 

 

 

 

 

3-10

Copyright © 2006 ARM Limited. All rights reserved.

ARM DDI 0389B

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SMC Networks PL241, AHB SRAM/NOR manual SMC Direct Command Register at