# HG changeset patch # User Mychaela Falconia # Date 1552804239 0 # Node ID 7cecc3dadbe7fccc0e75631bfe7287f0b7a6bf83 # Parent 9327935d854953dad6e720a9507f6f7aaed8e78a doc/SE-J100-target article written diff -r 9327935d8549 -r 7cecc3dadbe7 doc/SE-J100-target --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/doc/SE-J100-target Sun Mar 17 06:30:39 2019 +0000 @@ -0,0 +1,112 @@ +Sony Ericsson J100 target support in FreeCalypso +================================================ + +SE J100 is the last Calypso device target of OsmocomBB origin to be added to +FreeCalypso, joining the already-supported Mot C1xx and Pirelli DP-L10. This +target is really not interesting at all on its own merit, instead it has been +added to FC Magnetite for testing purposes: to verify that we are able to drive +this J100 variant of Compal's RFFE and produce correct RF Tx output as observed +with our CMU200 instrument. + +Despite being a Sony Ericsson rather than Motorola product (slightly different +case design, totally different battery and accessory connectors), in core +technical terms this SE J100 phone is still Compal, same as Mot C1xx. It is +technically closest to Mot C139, with only a few differences: + +* The display is different: same 96x64 pixel color, but a different model + requiring a different driver; + +* A ringtone player chip is used instead of the Calypso-driven buzzer; + +* There are a few differences in GPIO setup, in TSPACT signal usage for RF Tx + and in some RF Tx parameters (APC offset and Tx ramp templates) stemming from + the use of a slightly newer RF PA, such that a firmware image built for Mot + C139 or C11x should not be run on the J100, even if the LCD and the buzzer + are don't-cares. + +If you have one of these phones and wish to run FreeCalypso on it, follow the +procedure for Mot C139 in C1xx-Howto, with the following differences: + +* You need to build a firmware image specifically for the j100 target + (./configure.sh j100 hybrid-vpm), don't flash a c139 or c11x build. + +* Only the VPM configuration is available, not the proof-of-concept UI - the + LCD driver for the latter configuration exists only for the Mot C139 LCD, + not for SE J100 or any other C1xx. + +* It is not certain at all whether the battery charging configuration we have + for Mot C1xx is correct or not for SE J100 - see further below. + +Serial connection difficulty +============================ + +Connecting the serial interface (the obvious prerequisite before one can do any +kind of firmware hacking) is a lot more difficult on the SE J100 compared to +Mot C1xx. Following Sony Ericsson's product line, this J100 phone does not have +round-jack headset or charger connectors, instead all accessories (charger, +headsets, Calypso UART access) are connected through a multi-pin connector (12 +pins to be exact) that was used by SE across their product line. While there +exist a number of "cottage industry" vendors who make ready-to-use serial cables +for the kind of headset jack found in Mot C1xx phones, there does not appear to +be anyone making comparable cables for SE J100, thus the only way to play with +one of these phones is to construct the necessary serial cable yourself. + +The pins on SE's proprietary accessory connector which carry Calypso UART RxD +and TxD on the J100 are the same pins which carry USB data lines on some other +SE phones which (unlike J100) have an official data services / computer +connection function, thus there are two ways to hack together Calypso UART +access on the J100: + +Option 1: you can take a Sony Ericsson (or clone) USB-to-phone data cable and +mutilate it: cut off the USB end, split out the little wires and solder them to +your choice of 3.3 V USB-serial adapter. This is the route that was taken by +this author (Mother Mychaela), and when I did it, I ran into a nasty little +problem: the wires inside the cut-apart SE-clone USB-to-phone cable are +extremely thin (can't be any thicker than 28 AWG, and seemed to be even thinner +than that), and the solder contraption feels like it is barely holding, like it +is going to fall apart at any moment. + +Option 2: you can take the same SE (or clone) USB-to-phone data cable, but +instead of mutilating it, connect it to another custom contraption: if you can +find a USB female-A connector part to which you can solder your own wires (or +cut apart some other cable that terminates in a USB female-A socket), make a +cable contraption consisting of this USB female-A on one side (into which you +insert the unmodified SE cable) and your choice of 3.3 V USB-serial adapter on +the other end. I still have one more SE-clone data cable which I haven't cut, +so I might try this approach. + +For your choice of 3.3 V USB-serial adapter, you should definitely pick either +FT232R or CP2102, so you can use GSM-specific high baud rates (GSM-specific +because they derive from the 13 MHz clock) to transfer flash dumps and firmware +images. + +Battery charging problem +======================== + +Another problem stemming directly from SE's accessory connector arrangement is +that it is very difficult to connect both a charging power source and Calypso +UART access at the same time. At first I thought it was completely impossible +(there is only one accessory connector on the bottom of the phone), but then by +pure luck I acquired an unusual kind of SE charging adapter: this rare adapter +has a pass-through mechanical design, such that one can plug this charging +adapter into the phone and then piggy-back another accessory into it! However, +this kind of SE charging adapter is super-rare, and I haven't played with mine +yet because it has Europlug pins (not USA plug) on the AC power end, and I +haven't got around yet to acquiring the requisite AC plug adapter. + +Connecting both the charging power source and the Calypso UART at the same time +is important for two reasons: + +1) For me as the FreeCalypso developer, that is the only way I can develop and +test the charging configuration for this phone model. + +2) For "end users" of the voice pseudo-modem FreeCalypso fw configuration on +this target, if you have no serial connection, you have no way of seeing how +your charging progresses, as there is no LCD driver and the display stays dark +and non-functional. + +Because we don't have working battery charging on this SE J100 target yet, the +only safe way to play with this target at the present moment is to have two of +these phones (or another phone of a different model that takes the same +batteries), and keep one phone fully intact with its original fw so it can be +used to charge batteries when the FC-converted phone runs its battery down.