diff frbl/README @ 337:814d3f24bed6

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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--- a/frbl/README	Sat Mar 07 06:54:17 2020 +0000
+++ b/frbl/README	Thu Mar 12 20:46:33 2020 +0000
@@ -19,7 +19,19 @@
 for L1 and GPF.
 
 The test subdirectory is intended to contain our frbl1test and frbl2test
-programs; only frbl2test has been written so far.
+programs; only frbl2test has been written so far.  frbl2test implements the
+host downloader side of the protocol we call FRBL2 in the same way how FLUID
+(the PC-side application) implements it, allowing tests at both 115200 and
+230400 baud as explained below.  You need to provide a FreeCalypso-style (not
+TI-style) S-record image to be fed to the target bootloader; helloapp from
+freecalypso-tools/target-utils works ideally for this purpose.  Because this
+boot path does not go through the Calypso boot ROM, you will need to manually
+select helloapp-irda.srec or helloapp-modem.srec, matching the Calypso UART you
+are going through.  frbl1test will work the same way if I ever get around to
+writing it.
+
+230400 baud bogosity
+====================
 
 Aside from implementing two different serial protocols, TI's FRBL as featured
 in their Calypso firmwares has one other major quirk: both FRBL1 and FRBL2 were
@@ -39,5 +51,10 @@
 was clearly never intended or officially supported - instead the officially
 supported way for Leonardo and Leonardo-based customer designs was to use
 fluid -oo mode, which works through the boot ROM just like fc-loadtool.
-However, there is a possibility that Openmoko may have tried to turn this FRBL
-bug into a feature - we are still investigating.
+
+There is, however, an inexplicable mystery in that Openmoko seem to have used
+fluid -oO mode somehow (at least with their version of FLUID that may have
+unknown changes relative to TI's original) even though it should have never
+worked at all.  See this FreeCalypso community mailing list thread:
+
+https://www.freecalypso.org/pipermail/community/2020-March/000743.html