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doc/C155-target article written
author Mychaela Falconia <falcon@freecalypso.org>
date Sat, 13 Oct 2018 20:01:28 +0000
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8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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1 In the early years of FreeCalypso, when we made our first attempt at FC GSM
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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2 firmware that was eventually retired under the name Citrine, we supported
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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3 running that fw on the Mot C155/156 target in addition to the other two C1xx
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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4 subfamilies. However, that C155 target support in not available in our current
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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5 Magnetite and Selenite firmwares. We are not doing any work to support that
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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6 target in our current fw because it does not provide anything of value that is
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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7 not better provided by other targets:
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Mychaela Falconia <falcon@freecalypso.org>
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8
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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9 * If your goal is to have a practically usable phone, the simpler C139/140 is a
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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10 better choice than C155/156: C155 uses a ringtone generator chip for which no
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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11 docs could be found, thus we may not be able to make it ring (in contrast,
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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12 C139 uses a piezoelectric buzzer driven by the Calypso itself), and C155's
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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13 LCD controller is much less obvious than the one in the C139 - the latter
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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14 already works the way we like.
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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15
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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16 * If instead you would like a platform for playing with non-UI modem firmware
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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17 (which is all that our previous Citrine fw provided), then the only platform
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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18 which we officially support and endorse for that purpose is our own FCDEV3B.
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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19 It is not reasonable at this point to ask us to expend unpaid volunteer time
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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20 to support a hardware platform that is not made or sold by us when instead
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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21 you should be supporting our work by buying the hardware which we do make.
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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22
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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23 If you wish to strike out on your own and try to resurrect C155 target support
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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24 in FC Selenite or Magnetite, your first difficulty will be that you won't be
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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25 able to run our fw entirely out of RAM without flashing like we did when running
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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26 Citrine on this target. FC Citrine implemented an FFS-in-RAM hack as an
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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27 alternative to using a real FFS in flash, but this hack is not present in
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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28 Magnetite or Selenite, thus unless you go even further out and resurrect that
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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29 hack as well, you will have to flash your firmware. If you take the route of
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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30 flashing your fw, you will have to decide between one of two possible
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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31 approaches:
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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32
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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33 Approach 1: you can keep this target's original bootloader that expects the
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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34 main fw image to begin at 0x20000 with a hand-off interface that is new to the
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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35 C155 (different from the more basic C1xx subfamilies), and build your fw to fit
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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36 this C155 boot interface. This approach was supported in Citrine (although not
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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37 actually used because it was much easier to run via fc-xram w/o flashing) and
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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38 can be easily resurrected in the gcc build of Selenite. However, it would be a
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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39 lot more difficult to get this approach to work with TI's original TMS470
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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40 environment: doing so would require major surgery on their assembly code and
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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41 linker script magic, which I am not comfortable with because we have no docs or
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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42 sources for those assembler and linker tools. You will also face the same
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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43 problem if you resurrect our old FFS-in-RAM hack and try to build a fw image
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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44 that runs entirely out of RAM w/o flashing: it is easy to do in the gcc
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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45 environment, but not in TMS470.
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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46
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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47 Approach 2: you can replace the bootloader with the one we use on the more
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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48 basic C1xx phones (compal-flash-boot-for-fc.bin), in which case you will have
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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49 complications with loadtools (the ARM vs. Thumb entry point difference for
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Mychaela Falconia <falcon@freecalypso.org>
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50 serially loaded code), but you can work around that issue by running fc-loadtool
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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51 and fc-xram with -h c155 -c plain instead of just -h c155 after you change the
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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52 bootloader, or you can create yet another patched bootloader version that does
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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53 the Thumb entry point for serially loaded code like C155 original but hands off
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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54 to the main fw in flash in the older C1xx fashion. Either way you will then be
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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55 able to build flashable fw images for this boot-modified C155 in the same manner
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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56 as how we do it for the more basic C1xx targets, and thus have both TMS470 and
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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57 gcc environments.
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58
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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59 As you can see from the above, it will be messy and unpleasant no matter which
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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60 way you lick it, and we (FreeCalypso Central) are not going to do this work for
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Mychaela Falconia <falcon@freecalypso.org>
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61 free, whereas doing it on a commercial consulting basis would cost a lot more
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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62 than the $500 USD retail price of our own FreeCalypso development board
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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63 (FCDEV3B) that avoids all of these problems and is a much nicer platform for
8a15878740c1 doc/C155-target article written
Mychaela Falconia <falcon@freecalypso.org>
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64 Calypso sw/fw development.