Changeset 1614

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Timestamp:
08/08/09 04:32:20 (14 years ago)
Author:
jwoithe
Message:

RME: documentation corrections and minor updates

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  • trunk/libffado/doc/rme_notes/rme_config_register_map.txt

    r1612 r1614  
    22============================================ 
    33 
    4 Version: 0.14 
     4Version: 0.15 
    55Author: Jonathan Woithe 
    6 Date: 6 August 2009 
     6Date: 8 August 2009 
    77 
    88 
    …… 
    662662amplifiers can be set.  Mic channel gain is in steps of 1 dB from 10 dB up to 
    66366365 dB, with 0dB also available.  Instrument input gain ranges from 0 dB to 
    664 18 dB in 0.5 dB steps.  Output gains range from +6 dB down to -58 dB in 
    665 steps of 1 dB, with compete "mute" also available. 
     66418 dB in 0.5 dB steps.  Output gains range from +6 dB down to -53 dB (a 58 
     665dB range) in steps of 1 dB, with compete "mute" also available. 
    666666 
    667667The gains are set using the register at 0x801c0180. 
    668668 
    669   bits 31-24: 
     669  bits 31-24: unknown (set to 0) 
    670670  bits 23-16: channel being set (0=mic1, 1=mic2, 2=inst3, 4=inst4) 
    671   bits 15-8: 
     671  bits 15-8: unknown (set to 0) 
    672672  bits 7-0: the gain value 
    673673 
    …… 
    712712 
    713713Each fader control ranges from 0x00000000 (-inf) through 0x00008000 (0.0 dB) 
    714 up to a maximum of 0x00100000 (+6.0 dB).  The precise scale is still to be 
    715 worked out: -52.7 dB appears to correspond to a value of 0x0000004c, -46.6 dB  
    716 is 0x00000099. 
     714up to a maximum of 0x00010000 (+6.0 dB).  -52.7 dB appears to correspond to 
     715a value of 0x0000004c, -46.6 dB is 0x00000099.  From this we can see that if 
     716v is the value being written, the dB gain applied can be found using 
     717 
     718  dB = 20.log10(v/32768) 
     719 
     720Alternatively, to set the gain to G dB, one calculates the value to send to 
     721the device (v) using 
     722 
     723  v = 32768 * exp10(G/20) 
    717724 
    718725When setting the output fader controls, the associated output amplifier  
    …… 
    7467530x80081fec: maxtrix mixer ADAT2-8 output fader 
    747754 
    748 Each fader control ranges from 0x00000000 (-inf) through 0x00008000 (0.0dB) 
    749 and up to a maximum setting of 0x00010000 (+6.5dB). 
     755Each fader control ranges from 0x00000000 (-inf) through 0x00008000 (0.0 dB) 
     756and up to a maximum setting of 0x00010000 (+6.0 dB).  As for the 
     757Fireface-400, if v is the value being written, the dB gain applied can be 
     758found using 
     759 
     760  dB = 20.log(v/32768) 
    750761 
    751762Mute is synthesised by setting the respective send value to -inf (0).