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annotate Flash-boot-modes @ 23:14391ad53281

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FCDEV3B-repackaging article removed for legal reasons The idea expressed in that article, namely the idea that some party other than Mother Mychaela could be permitted to create a derived work based on FCDEV3B board design and have it be accepted into the FreeCalypso family, is no longer allowed by our current stance on the matters of intellectual property, particularly Falconia IP. For technical content, the new FC-modem-family and Quadband-ideas articles should fully supplant this old FCDEV3B-repackaging article.
author Mychaela Falconia <falcon@freecalypso.org>
date Wed, 23 Oct 2019 00:43:21 +0000
parents dc0e9c91d54a
children
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dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
parents:
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1 The Calypso chip includes an on-die boot ROM that allows the boot process to be
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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2 interrupted and diverted by an external host sending some special characters
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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3 into either of the two UARTs; this mechanism is what allows us to load code into
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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4 RAM and to reload the flash on Calypso GSM devices without having to resort to
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
parents:
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5 JTAG or chip desoldering or other extreme measures. In normal operation, when
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
parents:
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6 the boot path is NOT being diverted by an external serial download, the boot ROM
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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7 transfers control to the regular firmware in the flash - but there are two
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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8 different modes in which the flash fw image may be booted.
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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9
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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10 In order for the flash fw image to be considered bootable by the Calypso boot
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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11 ROM, the 32-bit word at flash address 0x2000 must equal either 0 or 1; if it
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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12 equals any other value, the boot ROM will consider the flash fw image to be
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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13 invalid (e.g., blank flash) and will wait forever for a serial download instead
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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14 of proceeding with flash boot. Depending on whether this word at 0x2000 equals
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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15 0 or 1, the flash fw image will be booted in one of two very different ways;
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
parents:
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16 we shall call them flash boot mode 0 and flash boot mode 1, respectively.
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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17
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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18 In flash boot mode 0 the following 32-bit word at flash address 0x2004 must
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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19 contain the address of the flash fw image entry point (ARM/Thumb selection in
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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20 the least-significant bit); the boot ROM will simply jump to this address with
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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21 a BX instruction. When the flash fw image is booted in this manner, the boot
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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22 ROM is still mapped at address 0 and the first 8 KiB of flash are inaccessible
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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23 except via the 0x03000000 alternate mapping, unless the firmware later changes
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
parents:
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24 the FFFF:FB10 register. This boot mode is intended for flash fw images that
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
parents:
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25 use the interrupt and exception vectors in the ROM (branching to IRAM addresses
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
parents:
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26 0x80001C-0x800034) for their interrupt and exception handling.
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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27
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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28 Flash boot mode 1 is different: instead of jumping directly to the flash fw
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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29 image, the boot ROM copies a small piece of its code into IRAM and jumps to that
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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30 code; the copied code disables the boot ROM via the FFFF:FB10 register (puts
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
parents:
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31 the external flash at address 0) and induces a processor reset through the
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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32 watchdog timer. It is not clear to us exactly what blocks are affected by the
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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33 watchdog reset, but bits 9:8 of the FFFF:FB10 register are not reset, hence
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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34 the ARM processor now boots from the reset vector in the flash as if the boot
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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35 ROM weren't there - and the latter really is not there after having disabled
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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36 itself.
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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37
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
parents:
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38 Flash boot mode 0 is only usable on Calypso C035 silicon (the "new" kind);
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
parents:
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39 while all commercial Calypso GSM devices targeted by FreeCalypso feature Calypso
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
parents:
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40 chips of the correct "new" kind, the people at TI who wrote and maintained their
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
parents:
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41 official firmware also had to work with older Calypso C05 chips featured on the
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
parents:
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42 early D-Sample and Leonardo boards. The earlier boot ROM code version in those
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
parents:
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43 early Calypso chips also implements the two boot modes which we call mode 0 and
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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44 mode 1, but its implementation of mode 0 is broken and unusable, therefore TI's
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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45 firmware people only used flash boot mode 1. On the other hand, newer firmware
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
parents:
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46 designs made for current rather than historical hardware will probably find
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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47 mode 0 to be cleaner, more intuitive and more convenient.
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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48
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
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49 All TI official firmwares use flash boot mode 1, our FreeCalypso Magnetite
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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50 firmware does likewise, being a direct derivative of TI's TCS211 fw, but our
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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51 gcc-built FC Selenite firmware uses flash boot mode 0, as the assembly code
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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52 pieces and linker script magic are entirely new (our own original design) in
dc0e9c91d54a Flash-boot-modes article added (migrated from freecalypso-tools)
Mychaela Falconia <falcon@freecalypso.org>
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53 the gcc-built version.