drive level is sent in the upper 4 bits

Fix from DL1YCF pihpsdr fork.

diff --git a/old_protocol.c b/old_protocol.c
index e84da5ce1b24588c6326dc00757bb1e1fe93d528..8d31e20aa3a5fed9bc035335b6fc6a33c4ca3fd6 100644 (file)
--- a/old_protocol.c
+++ b/old_protocol.c
@@ -1646,7 +1646,7 @@ void ozy_send_buffer() {
         {
         BAND *band=band_get_current_band();
         int power=0;
-static int last_power=0;
+       static int last_power=0;
        //
        // Some HPSDR apps for the RedPitaya generate CW inside the FPGA, but while
        // doing this, DriveLevel changes are processed by the server, but do not become effective.
@@ -1663,6 +1663,61 @@ static int last_power=0;
           } else {
             power=transmitter->drive_level;
           }
+
+         if (device == DEVICE_HERMES_LITE2) {
+             //
+             // from the "intended" drive level power, calculate the
+             // next lower TX attenuation which can be from 0.0 to -7.5 dB
+             // in 0.5 dB steps, encode the step in a four-bit word and shift
+             // it to the upper 4 bits.
+             // we always use the att level that produces a little bit *less* attenuation
+             // than required, and down-scale the IQ samples in transmitter.c
+             //
+             // NOTE: this down-scaling does not occur when connecting a CW key to the HL2
+             //       and using "internal" CW, because in this case the IQ samples are
+             //       generated in the FPGA. A typical symptom is that the CW signals are
+             //       stronger than the "TUNE" signal, and in the case of very low drive slider
+             //       values they can be *much* stronger.
+             //
+             // NOTE: When using predistortion (PURESIGNAL), the IQ scaling must be switched off.
+             //       In this case, the output  power can also be stronger than intended.
+             //
+             int hl2power;
+             if (power < 102) {
+                 hl2power=0;                   // -7.5 dB TX attenuation
+             } else if (power < 108) {
+                 hl2power=16;                  // -7.0 dB TX attenuation
+             } else if (power < 114) {
+                 hl2power=32;                  // -6.5 dB TX attenuation
+             } else if (power < 121) {
+                 hl2power=48;                  // -6.0 dB TX attenuation
+             } else if (power < 128) {
+                 hl2power=64;                  // -5.5 dB TX attenuation
+             } else if (power < 136) {
+                 hl2power=80;                  // -5.0 dB TX attenuation
+             } else if (power < 144) {
+                 hl2power=96;                  // -4.5 dB TX attenuation
+             } else if (power < 152) {
+                 hl2power=112;                 // -4.0 dB TX attenuation
+             } else if (power < 161) {
+                 hl2power=128;                 // -3.5 dB TX attenuation
+             } else if (power < 171) {
+                 hl2power=144;                 // -3.0 dB TX attenuation
+             } else if (power < 181) {
+                 hl2power=160;                 // -2.5 dB TX attenuation
+             } else if (power < 192) {
+                 hl2power=176;                 // -2.0 dB TX attenuation
+             } else if (power < 203) {
+                 hl2power=192;                 // -1.5 dB TX attenuation
+             } else if (power < 215) {
+                 hl2power=208;                 // -1.0 dB TX attenuation
+             } else if (power < 228) {
+                 hl2power=224;                 // -0.5 dB TX attenuation
+             } else {
+                 hl2power=240;                 // no      TX attenuation
+             }
+             power=hl2power;
+         }
         }
 
 //if(last_power!=power) {