changeset 11:f57f29dcc6d6

FCDEV3B-repackaging: updates for working MCSI and flash autodetect
author Mychaela Falconia <falcon@freecalypso.org>
date Thu, 28 Mar 2019 08:56:27 +0000
parents 17003ecbb9fc
children 9baf6215285b
files FCDEV3B-repackaging
diffstat 1 files changed, 14 insertions(+), 0 deletions(-) [+]
line wrap: on
line diff
--- a/FCDEV3B-repackaging	Thu Mar 28 08:04:00 2019 +0000
+++ b/FCDEV3B-repackaging	Thu Mar 28 08:56:27 2019 +0000
@@ -1,6 +1,9 @@
 Repackaging FreeCalypso modem into different physical form factors
 ==================================================================
 
+[This document was originally written in 2018-10; subsequent updates
+ are noted inline in the same bracketed form as this note.]
+
 As of this writing, our FreeCalypso Triband Modem Solution has reached the
 status of a finished product: it is no longer experimental or developmental,
 it is now fully fit for operational use on live public GSM networks in end user
@@ -65,6 +68,10 @@
   introduce a configuration management burden which we are not willing to
   take on.
 
+[2019-03 update: we now have working flash chip type autodetection, and
+ commercial modem products can use a smaller flash+RAM chip, specifically
+ Samsung K5A3240CTM or K5A3281CTM as used by Openmoko.]
+
 * Calypso's unused DSR_MODEM/LPG pin was left unconnected in Openmoko's version
   but on our FCDEV3B it is tied to GND on the board.  Other boards seeking to
   be FreeCalypso-compatible need to have this pin tied to GND as well because
@@ -141,6 +148,10 @@
 * A logic voltage level translating buffer to provide a reset to the flash chip
   that meets its timing requirements;
 
+[2019-03 update: the above is no longer required, you can now use one of the
+ smaller flash chips which are compatible with TI's silly FDP scheme and thus
+ don't need the extra translating buffer IC for reset.]
+
 * 3 pull-down resistors on GPIO3, MCSI_CLK and MCSI_FSYNCH;
 
 * Direct connections to GND on DSR_MODEM and MCSI_RXD pins.
@@ -169,6 +180,9 @@
 situation, the alternative way of tapping into VSP needs to be given
 consideration.
 
+[2019-03 update: we got MCSI working now, please read the Calypso-digital-voice
+ article for more info about both MCSI and VSP options.]
+
 Tapping into VSP is absolutely not possible on our current FCDEV3B, as the
 signals in question are currently routed directly from one BGA to another and
 do not come up to the surface at any accessible point.  The same situation holds