FreeCalypso > hg > fc-magnetite

annotate doc/FCDEV3B-hardware-bug @ 484:a1946652f71c

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
top README: update for the status of hybrid firmware
author Mychaela Falconia <falcon@freecalypso.org>
date Wed, 20 Jun 2018 08:18:48 +0000
parents 15c61c8f3166
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
474
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
1 Our current FCDEV3B boards exhibit a hardware bug: the reset input to the flash
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
2 chip is connected to Calypso's FDP output per both TI's Leonardo reference
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
3 schematics and Openmoko's working design, but this arrangement turns out to be
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
4 unsuitable for the high-capacity Spansion S71PL129NC0HFW4B flash+pSRAM chip we
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
5 are using, copied from Pirelli DP-L10. This hardware bug has manifested itself
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
6 in two different ways so far:
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
7
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
8 * Out of the 20 boards we've built so far, on just one board there was an issue
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
9 where our standard Magnetite fw would have trouble booting from flash, but
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
10 RAM-loaded fw booted fine. Interrupting the boot process serially and having
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
11 the serially loaded code jump to the image in flash also worked fine.
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
12 Eventually it was found that the flash boot problem on that one board occurs
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
13 only when flash boot mode 1 is used, whereas flash boot mode 0 works fine. I
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
14 (Mychaela) suspect that the problem has something to do with the watchdog
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
15 reset that happens as part of flash boot mode 1, the FDP output behaviour
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
16 during that watchdog reset, and the flash chip's reaction to the latter.
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
17
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
18 * On all of the boards there is a problem with sleep modes: when the firmware
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
19 is running from flash as opposed to RAM, certain sleep-wake sequences cause
483
15c61c8f3166 doc/FCDEV3B-hardware-bug: update on the investigation and the proposed fix
Mychaela Falconia <falcon@freecalypso.org>
parents: 474
diff changeset
20 an erratic self-reboot or a hang. Oscilloscope probing on a decased Pirelli
15c61c8f3166 doc/FCDEV3B-hardware-bug: update on the investigation and the proposed fix
Mychaela Falconia <falcon@freecalypso.org>
parents: 474
diff changeset
21 DP-L10 motherboard on which Calypso's FDP output is accessible seems to
15c61c8f3166 doc/FCDEV3B-hardware-bug: update on the investigation and the proposed fix
Mychaela Falconia <falcon@freecalypso.org>
parents: 474
diff changeset
22 confirm my (Mychaela's) suspicion that this FDP signal goes low during all
15c61c8f3166 doc/FCDEV3B-hardware-bug: update on the investigation and the proposed fix
Mychaela Falconia <falcon@freecalypso.org>
parents: 474
diff changeset
23 sleep modes, and the current working hypothesis is that our Spansion flash
15c61c8f3166 doc/FCDEV3B-hardware-bug: update on the investigation and the proposed fix
Mychaela Falconia <falcon@freecalypso.org>
parents: 474
diff changeset
24 chip gets unhappy with the reset timing it gets subjected to, and some flash
15c61c8f3166 doc/FCDEV3B-hardware-bug: update on the investigation and the proposed fix
Mychaela Falconia <falcon@freecalypso.org>
parents: 474
diff changeset
25 reads (instruction fetches) don't work after wakeup. So far the only workable
474
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
26 solution has been to disable all sleep modes in all FCDEV3B fw builds;
483
15c61c8f3166 doc/FCDEV3B-hardware-bug: update on the investigation and the proposed fix
Mychaela Falconia <falcon@freecalypso.org>
parents: 474
diff changeset
27 nothing else has been successful. However, re-enabling all of these sleep
15c61c8f3166 doc/FCDEV3B-hardware-bug: update on the investigation and the proposed fix
Mychaela Falconia <falcon@freecalypso.org>
parents: 474
diff changeset
28 modes with AT%SLEEP=4 works fine when the firmware image executes out of RAM
15c61c8f3166 doc/FCDEV3B-hardware-bug: update on the investigation and the proposed fix
Mychaela Falconia <falcon@freecalypso.org>
parents: 474
diff changeset
29 instead of flash, further supporting our current working hypothesis as to the
15c61c8f3166 doc/FCDEV3B-hardware-bug: update on the investigation and the proposed fix
Mychaela Falconia <falcon@freecalypso.org>
parents: 474
diff changeset
30 root cause.
474
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
31
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
32 The fcdev3b-hacks directory contains two hacks that can be applied to FCDEV3B
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
33 firmware images (fwimage.bin builds) as xxd binary patches:
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
34
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
35 * The first hack dating from 2017-05 patches the fw to use flash boot mode 0
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
36 instead of TI's original flash boot mode 1, but after boot the FFFF:FB10
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
37 register is set to put the flash and not the internal ROM at address 0, so
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
38 the interrupt and exception vectors go to the flash like in TI's original fw,
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
39 not through the internal ROM. This hack was put together for the purpose of
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
40 producing flashable fw images that boot without problems on that one board on
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
41 which flash boot mode 1 didn't work, and worked successfully for that purpose.
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
42
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
43 * The second hack dating from 2018-03 patches the fw to not only use flash boot
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
44 mode 0, but also route the interrupt and exception vectors through Calypso's
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
45 internal ROM. I was hoping that this hack would make the sleep mode problem
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
46 go away by having the Calypso execute some cycles out of its internal ROM and
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
47 RAM before hitting the flash after wakeup, but nope, bringing up the SIM
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
48 interface with AT+CFUN=1 in the l1reconst config when running from flash with
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
49 small sleep enabled still triggers erratic misbehaviour even with this patch.
8fbf3c0ea8b6 doc: Flash-boot-mode-hack article replaced with FCDEV3B-hardware-bug
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
50
483
15c61c8f3166 doc/FCDEV3B-hardware-bug: update on the investigation and the proposed fix
Mychaela Falconia <falcon@freecalypso.org>
parents: 474
diff changeset
51 The proper fix will require a new PCB spin to change the flash reset wiring:
15c61c8f3166 doc/FCDEV3B-hardware-bug: update on the investigation and the proposed fix
Mychaela Falconia <falcon@freecalypso.org>
parents: 474
diff changeset
52 instead of driving it with Calypso's FDP output, use the ON_nOFF master reset
15c61c8f3166 doc/FCDEV3B-hardware-bug: update on the investigation and the proposed fix
Mychaela Falconia <falcon@freecalypso.org>
parents: 474
diff changeset
53 signal from Iota's VRPC block, fed through a logic voltage level translating
15c61c8f3166 doc/FCDEV3B-hardware-bug: update on the investigation and the proposed fix
Mychaela Falconia <falcon@freecalypso.org>
parents: 474
diff changeset
54 buffer to change it from 1.5 V to 2.8 V logic. The flash chip we are using has
15c61c8f3166 doc/FCDEV3B-hardware-bug: update on the investigation and the proposed fix
Mychaela Falconia <falcon@freecalypso.org>
parents: 474
diff changeset
55 lower power consumption when it is NOT held in reset, hence unlike TI's intent
15c61c8f3166 doc/FCDEV3B-hardware-bug: update on the investigation and the proposed fix
Mychaela Falconia <falcon@freecalypso.org>
parents: 474
diff changeset
56 with FDP, we don't want our flash chip to go into reset during any sleep at all.
15c61c8f3166 doc/FCDEV3B-hardware-bug: update on the investigation and the proposed fix
Mychaela Falconia <falcon@freecalypso.org>
parents: 474
diff changeset
57
15c61c8f3166 doc/FCDEV3B-hardware-bug: update on the investigation and the proposed fix
Mychaela Falconia <falcon@freecalypso.org>
parents: 474
diff changeset
58 The new PCB revision with this change is now in the process of being finalized,
15c61c8f3166 doc/FCDEV3B-hardware-bug: update on the investigation and the proposed fix
Mychaela Falconia <falcon@freecalypso.org>
parents: 474
diff changeset
59 and we will soon need the funding to produce the new boards. Anyone who is
15c61c8f3166 doc/FCDEV3B-hardware-bug: update on the investigation and the proposed fix
Mychaela Falconia <falcon@freecalypso.org>
parents: 474
diff changeset
60 interested in helping to make FCDEV3B V2 a reality should email Mychaela.