diff options
Diffstat (limited to 'src/target/firmware/board/gta0x/rffe_gta0x_triband.c')
| -rw-r--r-- | src/target/firmware/board/gta0x/rffe_gta0x_triband.c | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/src/target/firmware/board/gta0x/rffe_gta0x_triband.c b/src/target/firmware/board/gta0x/rffe_gta0x_triband.c index b520f656..dcb9ca9d 100644 --- a/src/target/firmware/board/gta0x/rffe_gta0x_triband.c +++ b/src/target/firmware/board/gta0x/rffe_gta0x_triband.c @@ -7,10 +7,22 @@ #include <calypso/tsp.h> #include <rf/trf6151.h> -/* This is a value that has been measured on the C123 by Harald: 71dBm, - it is the difference between the input level at the antenna and what - the DSP reports, subtracted by the total gain of the TRF6151 */ -#define SYSTEM_INHERENT_GAIN 71 +/* + * OsmocomBB's definition of system inherent gain is similar to what is + * called "magic gain" (GMagic) in TI's architecture, except that TI's + * GMagic includes TRF6151 LNA gain whereas OBB's definition of system + * inherent gain does not. TI's GMagic is also reckoned in half-dB units + * instead of integral dB. The RF tract is identical between Openmoko + * GTA0x and FreeCalypso FCDEV3B boards, both manufacturers' devices + * have had their GMagic calibrated per unit at the center frequency + * of each supported downlink band at the respective factories, and all + * calibrated values on defect-free units fall in the range between 199 + * to 202, with 200 as the round median value. Setting OsmocomBB's notion + * of system inherent gain to 73 dB produces an equivalent of GMagic=200 + * in TI's universe, which is more correct than the previous setting of + * 71 dB copied from Compal/Motorola phones, which have a different RFFE. + */ +#define SYSTEM_INHERENT_GAIN 73 /* describe how the RF frontend is wired on the Openmoko GTA0x boards */ |