Cirrus Logic CS4953xx - Manual (Page 82)

SDRAM/Flash Controller Interface
CS4953xx Hardware User’s Manual
DS732UM10 Copyright 2010 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
Table 8-2 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
SD_D3/EXT_D3 SDRAM/Flash Bidirectional Data Bit 3 34 63 BiDir
SD_D4/EXT_D4 SDRAM/Flash Bidirectional Data Bit 4 32 61 BiDir
SD_D5/EXT_D5 SDRAM/Flash Bidirectional Data Bit 5 31 60 BiDir
SD_D6/EXT_D6 SDRAM/Flash Bidirectional Data Bit 6 30 59 BiDir
SD_D7/EXT_D7 SDRAM/Flash Bidirectional Data Bit 7 29 58 BiDir
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 8-1. SDRAM Interface Signals (Continued)
Signal Name Signal Description
LQFP-144
Pin #
LQFP-128
Pin #
Pin Type