Engineer-To-Engineer Note EE-19 a
Contents
1. Phone 800 ANALOG D FAX 781 461 3010 FTP ftp analog com EMAIL dsp support analog com Below is a set of logic equations used in a Motorola S Record File Format programmable logic device that is between the DSP Bad thas boot memory devic The 8 bit Motorola S Record File Format is a printable ASCII format consisting of an optional Note any signals with a in front are negated header record and one or more data records followed by an end of file record Data records may appear in any order Values are represented as 2 or 4 hexadecimal digit values If an input or output signal has a in front it is negated when the signal enters or leaves the programmable logic device Definiti inputs Aid alo ane gt eddvees anes from the DSP Start of record mark letter S DMS PMS negated select lines from Record type field O for header 1 for data 9 for DSP end of record All other record types are ignored D22 D23 raava lines from pe Dee Length field Number of bytes to follow Address field Add f first byte output EAl1 EAl2 EA13 EAl4 All Data field A14 of boot memory device JES boot memory select CC Checksum field One s complement of the length address and data fields modulo 256 1 equations EA11 A13 BMS All PMS Table 3 Motorola S Record Format EA12 D22 BMS A12 PMS Example EA13 D23 BMS A13 PMS S0030000FC EA14 BMS PMS S12. and 32 boot pages e Mapping program memory and data memory into boot memory for large amounts of 8 bit wide storage e Modifying the boot memory image file e Description of an example system using all of the above concepts These methods can be complicated to implement yet can effectively streamline certain applications For more information on boot pages see section 10 4 of the ADSP 21xx Family User s Manual or the following Analog Devices Engineers Note Boot Paging I FAQ Boot Pages on the 21xx Family DSP s excluding 218x amp CSPO1 XXX Boot Memory Overview The Analog Devices ADSP 21xx family of Digital Signal Processors DSP have a built in booting routine that loads 24 bit program memory PM into internal RAM from an 8 bit boot memory device Booting can occur automatically when the DSP is reset and or while the DSP is running Boot memory is divided into eight pages Each page holds an entire memory image of the DSP s internal PM When configured to load PM from boot memory at reset the DSP automatically loads boot page 0 Each 24 bit program memory word is stored in 4 bytes of boot memory Therefore the length of a boot page in bytes is always 4 times the number of PM words stored within it This boot memory device is most commonly a ROM of some sort but can be any memory device FLASH RAM static RAM or another processor as long as it is fast enough and compatible with the DSP s external
3. is removed A DSP with 512 bytes of PM such as the ADSP 2105 2115 2163 and 2164 need only 2048 bytes to be read from each boot page because the internal PM is only 512 words long By removing pins A11 and A12 from the boot memory and reconnecting pins A13 D22 and D23 boot page select lines on the DSP to A11 A12 and A13 respectively on the boot memory the 6Kbytes per boot page that was previously unused is now eliminated and the pages are packed next to each other The result is 8 boot pages stored in 128 Kbits of boot memory as opposed to the original 512 Kbits In a system that uses a DSP with 1K of PM such as the ADSP 2101 2108 2161 2162 and 2111 each boot page is 4096 bytes in length because the internal PM is 1024 words long Only pin A12 is removed and pins A13 D22 and D23 move down one address line The result is 8 boot pages stored in 256 Kbits of boot memory verses the original 512 Kbits Table 1 summarizes these relationships For more information see Section 5 4 in the ADSP 2100 Assembler Tools and Simulator Manual Total PM Min Size Address in DSP of BM Lines Left words Kbits Disconnected Table 1 DSP Boot Memory Sizes Creating Multiple Boot Page Banks To create a system that uses more than 8 boot pages the boot memory must be an order of 2x larger than the minimum size of boot memory as defined in Table 1 A boot memory size of 2x yields 16 boot pages 4x yields 32 boot pages Every ti
4. memory interface Basic Boot Memory Interface The standard method used to connect an ADSP 21xx DSP to boot memory is to connect pins A0 A13 of the external DSP bus to pins A0 A13 of the boot memory and pins D22 and D23 of the DSP to pins A14 and A15 of the boot memory Pins A0 A12 cycle through the 8192 locations of each page Pins A138 D22 and D23 select the page This interface requires a minimum of 512 Kbits of boot memory The ADSP 21xx family DSPs built in boot page loading hardware assumes that the boot pages will be 8 Kbytes apart in boot memory For example boot page 0 starts at boot memory address 0 boot page 1 starts at boot memory address 0x2000 hex etc If your system uses a DSP that has less than 2Kwords of program memory there is unused memory within each boot page in the boot memory For instance the ADSP 2115 has only 512 words of PM and requires 2 Kbytes of boot memory space per boot page This leaves 6 Kbytes of boot memory unused per boot page If the ADSP 2115 system uses all eight boot pages with this addressing scheme the system requires 512 Kbits of boot ANALOG DEVICES memory This 512 Kbit boot memory has a maximum of 2K x 8 16 Kbytes worth of boot data and a minimum of 6K x 8 48 Kbytes of unused data Figure 2 shows a memory map of this allocation scheme Removing Unused Memory By rewiring the address lines from the DSP to the boot memory the unused memory a minimum of 6K x 8 48 Kbytes
5. 090100010203040506E0 S9030000FC Intel Hex File Format Sas Note The first line in the above example Motorola The 8 bit Intel Hex File Format is a printable S Record header record The second line is a data ASCII format consisting of one or more data records record addressed at location 100 with data values 1 followed by an end of file record Each record to 6 The third line is the end of file record consists of one line of information Data records may appear in any order Address and data values are represented as 2 or 4 hexadecimal digit values Length field Number of data bytes Address field Address of first byte Record type field O0 for data and 01 for end of record Data field Checksum field One s complement of length address record type and data fields modulo 256 Table 2 Intel Hex Record Format Example gt 06010000010203040506E4 00000001FF EN 19 Page 4 Technical Notes on using Analog Devices DSP components and development tools Phone 800 ANALOG D FAX 781 461 3010 FTP ftp analog com EMAIL dsp support analog com Memory Maps For 2 ADSP 2115 Systems 512 words of program memory ROM DSP ROM DSP Address Address Address Address 0x0800 0x2000 0x1000 0x4000 0x1000 0x6000 0x2000 0x8000 0x2000 0x2000 Boot Boot Boot 0x3000 Page 6 0xC000 Page 7 0xE000 OxFFFF EE Bank 0x4000 JBoot Page 2 0x4000 0x0800 0x3800 0x4000 0x4800 External Pr
6. Engineer To Engineer Note FE 19 Technical Notes on using Analog Devices DSP components and development tools Phone 800 ANALOG D FAX 781 461 3010 EMAIL dsp support analog com FTP ftp analog com WEB www analog com dsp Copyright 1999 Analog Devices Inc All rights reserved Analog Devices assumes no responsibility for customer product design or the use or application of customers products or for any infringements of patents or rights of others which may result from Analog Devices assistance All trademarks and logos are property of their respective holders Information furnished by Analog Devices Applications and Development Tools Engineers is believed to be accurate and reliable however no responsibility is assumed by Analog Devices regarding the technical accuracy of the content provided in all Analog Devices Engineer to Engineer Notes Boot Paging II Maximizing Boot Memory Efficiency on the ADSP 21xx family DSP s excluding the ADSP 218x Contributed by Dan L Last Modified 10 20 97 Introduction This document provides various strategies to increase the efficiency and usefulness of standard boot memory in 21xx systems excluding the ADSP 218x The following topics are covered e Maximizing the efficiency of boot page allocation within the boot memory of your ADSP 21xx system e Selecting the smallest boot memory device possible for your ADSP 21xx system e Creating multi bank boot page systems with 16
7. me the boot memory is increased 2x there is one EN 19 unused address line added as the most significant unused address line of the boot memory These unused lines can be tied to a memory mapped flip flop in a DSP system To load a boot page from another bank first write to the flip flop and specify the bank then write to the System Control Register SYSCON and write the boot page number The unused bits may also be connected to hard switches or to an entirely separate system To connect these unused bits the actual boot memory image file s created by the 21xx splitter must be modified See Modifying the Boot Memory Image file section later in this article Mapping PM or DM Space into Boot Memory With a little logic between the ADSP 2115 and boot memory it is possible to map PM and or DM into unused portions of the boot memory Although this data is only 8 bits wide it can store other data such as function look up tables and or data constants To map PM and or DM into unused portions of the boot memory both the boot memory select pin BMSL and data or program memory select PMSL pins must logically select different sections of the boot memory In addition the 14 address lines from the DSP must connect directly to the 14 least significant address lines of the boot memory Less than 14 address lines can be used to allocate a smaller block of PM or DM but they should be contiguously connected on both the DSP and bo
8. n the BNM generated by the splitter must be edited manually see Tables 2 and 3 for a description of both Intel Hex and Motorola S data formats Using a text editor 1 load each BNM file and 2 patch them together The address fields of each bnm file must be modified to reflect the new location in boot memory except for bank 0 which always begins at zero Mapping Program and Data Memory into Boot Memory Space To place data into the data and program memory mapped areas of boot memory the bnm file created by the splitter must be edited manually with a text editor The following steps describe this procedure 1 Determine the boot memory address where the data begins 2 Create an addendum containing the data and paste it onto the end of the bnm file 3 Save the original The following is an example demonstrating this process The original bnm file created by the splitter in Motorola S format SOO030000FC S 12500001806203421 9A00FF S9030000FC EN 19 Original Data to be stored in memory mapped program memory follows 00 O1 03 04 06 O7 08 OA OC OE The following data is put into Motorola S format starting at address 4800 S 1254800000103040607080A0COE Insert the following into the original bnm file SOO30000FC 12500001806203421 9A00FFE S 1254800000103040607080A0COE S9030000FC In this example system PM is mapped to the boot memory address 0x4800 see Figure 1 A seq
9. ogram Pata 0x6000 Boot Page 3 0x6000 Memory Ox3FFF 0x8000 SE ODOR 0x8000 Boot Page 4 0x8000 0x8800 0x2000 0x9000 0x4000 0x9800 0x6000 0xA000 0x8000 0xA000 JBoot Page 5 0xA000 0xA800 0xA000 0xB000 0xC000 0xB800 0xE000 B k 0xC000 an 0xC000 JBoot Page 6 0xC000 0xC800 0x4800 i External Program Rete 0xE000 JBoot Page 7 0xE000 Memory Figure 1 Memory Map Highly Excellent Boot Memor s OxFF RE Gee oa Ox3FFF Y OxFFFF OxFFFF Mapped into BM m Mapped into PM amp DM Unused L Mapped into BM Unused Figure 2 Memory Map Basic Boot Memory Interface with 2048 byte boot pages EN 19 Page 5 Technical Notes on using Analog Devices DSP components and development tools Phone 800 ANALOG D FAX 781 461 3010 FTP ftp analog com EMAIL dsp support analog com
10. ot memory If no memory efficient allocation scheme is used this method is not necessary page packing If this scheme is used additional logic is needed to allow BM DM and PM accesses to function correctly Modifying the Boot Memory Image file If you alter the configuration of the address lines between the DSP and the boot memory the ASCII boot memory image file bnm created by the splitter must also be modified to reflect these changes In many cases a simple text editor macro can perform all of the required modifications Below are descriptions of the various boot memory image file modifications required for the various schemes described throughout this document Page 2 Technical Notes on using Analog Devices DSP components and development tools Phone 800 ANALOG D FAX 781 461 3010 FTP ftp analog com EMAIL dsp support analog com Removing address lines to pack boot pages next to each other The following switch must be used in the splitter s command line to set the boot boundary between pages e For boot pages 4096 bytes apart DSP s with 1Kwords of program memory bb 1024 e For boot pages 2048 bytes apart for DSP s with 512 words of program memory bb S12 although this is not listed as an option for the splitter it will work Using Multiple Boot Page Banks To use Multiple Boot Page Banks each bank of boot pages is generated separately by the splitter The
11. uence of 8 bit values located in this range must be manually inserted into the bnn file Describing An Example System The example system described here uses an ADSP 2115 with 512 bytes of PM a 512 Kbit boot memory device and a programmable logic device The system has 2 banks of 8 boot pages each 2048 bytes long since there is only 512 program memory words to load and 2 x 14K banks of 8 bit wide PM See Figure 1 Because you need only 2048 bytes per boot page pins AO A10 of the DSP cycle through the 2048 locations of each boot page To select the boot pages connect pins A13 D22 and D23 of the DSP to pins A11 A13 of the boot memory only while accessing boot memory This packs the boot pages next to each other so they are all 2048 bytes apart vs 8192 bytes apart Pin A14 of the boot memory device is used to select access of the boot pages or the 8 bit PM in boot memory Pin A15 of the boot memory device can be set high or low to yield two banks of boot page and PM blocks In the example system pin A15 is connected to a memory mapped D flip flop located in data memory space providing a total of 16 boot pages in the system To load a page from bank 1 into memory after page 0 has been loaded into PM set A15 to a logical high by writing to the memory mapped flip flop and initiate the automated boot page loading procedure Page 3 Technical Notes on using Analog Devices DSP components and development tools
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