SDRAM/Flash Controller Interface
CS4953xx Hardware Users Manual
DS732UM7
Copyright 2008 Cirrus Logic, Inc
8-4
8.3.2 Configuring SDRAM/Flash Parameters
IMPORTANT NOTICE: External memory is enabled by default. On systems that do not use external
memory, the command, 0x8100005c 0x00000000 must be sent to the DSP before kickstart to disable external
memory.
Not all Flash and EEPROM manufacturers conform to the same timing specifications. Therefore, the CS4953xx
DSP must be configured to match the timing specifications for the Flash and EEPROM being used. The messages
shown in
must be sent prior to kickstarting downloaded application code.
Note: All External Memory Interface config messages must be sent to DSPB. For more details on sending
messages to DSP B refer to AN288, section 2.1.4
Refer to External Memory Interface in the CS4953xx data sheet for timing parameters that are summarized in
SD_D8/EXT_D8
SDRAM/Flash Bidirectional Data Bit 8
49
78
BiDir
SD_D9/EXT_D9
SDRAM/Flash Bidirectional Data Bit 9
48
77
BiDir
SD_D10/EXT_D10
SDRAM/Flash Bidirectional Data Bit 10
46
75
BiDir
SD_D11/EXT_D11
SDRAM/Flash Bidirectional Data Bit 11
45
74
BiDir
SD_D12/EXT_D12
SDRAM/Flash Bidirectional Data Bit 12
43
72
BiDir
SD_D13/EXT_D13
SDRAM/Flash Bidirectional Data Bit 13
42
71
BiDir
SD_D14/EXT_D14
SDRAM/Flash Bidirectional Data Bit 14
41
70
BiDir
SD_D15/EXT_D15
SDRAM/Flash Bidirectional Data Bit 15
40
69
BiDir
EXT_CS1
Flash Chip Select (active low)
90
119
Output
EXT_OE
Flash Output Enable (active low)
89
118
Output
EXT_WE
Flash Write Enable (active low)
38
66
Output
EXT_CS2
SRAM Chip Select (active low)
(CURRENTLY NOT SUPPORTED)
65
94
Output
a. For 16-Mbit parts, SD_BA0 is used as a bank select. For 64-Mbit and 128-Mbit parts SD_BA[1:0] is the 2-
bit bank select.
Table 8-2. SDRAM/Flash Controller Parameters
Mnemonic
Hex Message
Extmem_Setup_Control
Bit 31:5 = 0 = Reserved
Bit 4 = 0/1 = Disable/Enable Flash port
Bit 3:1 = 0 = Reserved
Bit 0 = 0/1 = Disable/Enable SDRAM port
0x8100005C
0xHHHHHHHH
Default: 0x00000011
Table 8-1. SDRAM Interface Signals (Continued)
Signal Name
Signal Description
LQFP-
144 Pin
#
LQFP-
128 Pin
#
Pin Type
Содержание CS4953xx
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