Manual

SDRAM/Flash Controller Interface

CS4953xx Hardware User’s Manual

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