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comparison frbl/README @ 337:814d3f24bed6

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frbl/README: minor updates
author Mychaela Falconia <falcon@freecalypso.org>
date Thu, 12 Mar 2020 20:46:33 +0000
parents 9805020b6834
children
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336:9805020b6834 337:814d3f24bed6
17 poor quality because these particular COFF objects have only minimal symbolic 17 poor quality because these particular COFF objects have only minimal symbolic
18 information required for linking, as opposed to the much richer -g kind we got 18 information required for linking, as opposed to the much richer -g kind we got
19 for L1 and GPF. 19 for L1 and GPF.
20 20
21 The test subdirectory is intended to contain our frbl1test and frbl2test 21 The test subdirectory is intended to contain our frbl1test and frbl2test
22 programs; only frbl2test has been written so far. 22 programs; only frbl2test has been written so far. frbl2test implements the
23 host downloader side of the protocol we call FRBL2 in the same way how FLUID
24 (the PC-side application) implements it, allowing tests at both 115200 and
25 230400 baud as explained below. You need to provide a FreeCalypso-style (not
26 TI-style) S-record image to be fed to the target bootloader; helloapp from
27 freecalypso-tools/target-utils works ideally for this purpose. Because this
28 boot path does not go through the Calypso boot ROM, you will need to manually
29 select helloapp-irda.srec or helloapp-modem.srec, matching the Calypso UART you
30 are going through. frbl1test will work the same way if I ever get around to
31 writing it.
32
33 230400 baud bogosity
34 ====================
23 35
24 Aside from implementing two different serial protocols, TI's FRBL as featured 36 Aside from implementing two different serial protocols, TI's FRBL as featured
25 in their Calypso firmwares has one other major quirk: both FRBL1 and FRBL2 were 37 in their Calypso firmwares has one other major quirk: both FRBL1 and FRBL2 were
26 implemented on 13 MHz platforms (the original purpose was to facilitate fw 38 implemented on 13 MHz platforms (the original purpose was to facilitate fw
27 loading on TI's earlier DBB chips before Calypso that didn't have the boot ROM 39 loading on TI's earlier DBB chips before Calypso that didn't have the boot ROM
37 to it at 230400 baud instead of TI's intended 115200 baud. TI's official 49 to it at 230400 baud instead of TI's intended 115200 baud. TI's official
38 version of FLUID does not support FRBL entry at 230400 baud and such operation 50 version of FLUID does not support FRBL entry at 230400 baud and such operation
39 was clearly never intended or officially supported - instead the officially 51 was clearly never intended or officially supported - instead the officially
40 supported way for Leonardo and Leonardo-based customer designs was to use 52 supported way for Leonardo and Leonardo-based customer designs was to use
41 fluid -oo mode, which works through the boot ROM just like fc-loadtool. 53 fluid -oo mode, which works through the boot ROM just like fc-loadtool.
42 However, there is a possibility that Openmoko may have tried to turn this FRBL 54
43 bug into a feature - we are still investigating. 55 There is, however, an inexplicable mystery in that Openmoko seem to have used
56 fluid -oO mode somehow (at least with their version of FLUID that may have
57 unknown changes relative to TI's original) even though it should have never
58 worked at all. See this FreeCalypso community mailing list thread:
59
60 https://www.freecalypso.org/pipermail/community/2020-March/000743.html