24 May
2012
24 May
'12
8:42 a.m.
Fix selection of VCO band (needed for example to get to 166 MHz) for
the FC0012 tuner, and add a lot of register descriptions.
Signed-Off-by: Michael Karcher <osmosdr(a)mkarcher.dialup.fu-berlin.de>
---
src/tuner_fc0012.c | 49 +++++++++++++++++++++++++++++++++----------------
1 file changed, 33 insertions(+), 16 deletions(-)
diff --git a/src/tuner_fc0012.c b/src/tuner_fc0012.c
index 104a4f7..2d66f3c 100644
--- a/src/tuner_fc0012.c
+++ b/src/tuner_fc0012.c
@@ -20,21 +20,35 @@
/* Incomplete list of register settings:
*
* Name Reg Bits Desc
+ * CHIP_ID 0x00 0-7 Chip ID (constant 0xA1)
+ * RF_A 0x01 0-3 Number of count-to-9 cycles in RF
+ * divider (suggested: 2..9)
+ * RF_M 0x02 0-7 Total number of cycles (to-8 and to-9)
+ * in RF divider
+ * RF_K_HIGH 0x03 0-6 Bits 8..14 of fractional divider
+ * RF_K_LOW 0x04 0-7 Bits 0..7 of fractional RF divider
+ * RF_OUTDIV_A 0x05 3-7 Power of two required?
* LNA_POWER_DOWN 0x06 0 Set to 1 to switch off low noise amp
- * VCO_SPEED 0x06 3 Set the speed of the VCO. example
- * driver hardcodes to 1 for some reason
+ * RF_OUTDIV_B 0x06 1 Set to select 3 instead of 2 for the
+ * RF output divider
+ * VCO_SPEED 0x06 3 Select tuning range of VCO:
+ * 0 = Low range, (ca. 1.1 - 1.5GHz)
+ * 1 = High range (ca. 1.4 - 1.8GHz)
* BANDWIDTH 0x06 6-7 Set bandwidth. 6MHz = 0x80, 7MHz=0x40
* 8MHz=0x00
* XTAL_SPEED 0x07 5 Set to 1 for 28.8MHz Crystal input
* or 0 for 36MHz
+ * <agc params> 0x08 0-7
* EN_CAL_RSSI 0x09 4 Enable calibrate RSSI
* (Receive Signal Strength Indicator)
* LNA_FORCE 0x0d 0
* AGC_FORCE 0x0d ?
- * LNA_GAIN 0x13 0-4 Low noise amp gain
+ * LNA_GAIN 0x13 3-4 Low noise amp gain
* LNA_COMPS 0x15 3 ?
* VCO_CALIB 0x0e 7 Set high then low to calibrate VCO
- *
+ * (fast lock?)
+ * VCO_VOLTAGE 0x0e 0-6 Read Control voltage of VCO
+ * (big value -> low freq)
*/
/* glue functions to rtl-sdr code */
@@ -99,12 +113,11 @@ void FC0012_Dump_Registers()
DEBUGF("LNA Force:\t%s\n", (regBuf & 0x1) ? "Forced" : "Not
Forced");
FC0012_Read(pTuner, 0x13, ®Buf);
DEBUGF("LNA Gain:\t");
- switch (regBuf) {
- case (0x10): DEBUGF("19.7dB\n"); break;
- case (0x17): DEBUGF("17.9dB\n"); break;
- case (0x08): DEBUGF("7.1dB\n"); break;
- case (0x02): DEBUGF("-9.9dB\n"); break;
- default: DEBUGF("unknown gain value 0x02x\n");
+ switch (regBuf & 0x18) {
+ case (0x00): DEBUGF("Low\n"); break;
+ case (0x08): DEBUGF("Middle\n"); break;
+ case (0x10): DEBUGF("High\n"); break;
+ default: DEBUGF("unknown gain value 0x18\n");
}
#endif
}
@@ -173,7 +186,7 @@ void FC0012_Frequency_Control(unsigned int Frequency, unsigned short
Bandwidth)
int FC0012_SetFrequency(void *pTuner, unsigned long Frequency, unsigned short Bandwidth)
{
- int VCO1 = 0;
+ int VCO_band = 0;
unsigned long doubleVCO;
unsigned short xin, xdiv;
unsigned char reg[21], am, pm, multi;
@@ -230,7 +243,7 @@ int FC0012_SetFrequency(void *pTuner, unsigned long Frequency,
unsigned short Ba
doubleVCO = Frequency * multi;
reg[6] = reg[6] | 0x08;
- VCO1 = 1;
+ VCO_band = 1;
xdiv = (unsigned short)(doubleVCO / (CrystalFreqKhz / 2));
if( (doubleVCO - xdiv * (CrystalFreqKhz / 2)) >= (CrystalFreqKhz / 4) )
xdiv = xdiv + 1;
@@ -269,7 +282,6 @@ int FC0012_SetFrequency(void *pTuner, unsigned long Frequency,
unsigned short Ba
if (FC0012_Write(pTuner, 0x03, reg[3])) return -1;
if (FC0012_Write(pTuner, 0x04, reg[4])) return -1;
//reg[5] = reg[5] | 0x07; // This is really not cool. Why is it there?
- // Same with hardcoding VCO=1
if (FC0012_Write(pTuner, 0x05, reg[5])) return -1;
if (FC0012_Write(pTuner, 0x06, reg[6])) return -1;
@@ -277,16 +289,19 @@ int FC0012_SetFrequency(void *pTuner, unsigned long Frequency,
unsigned short Ba
if (FC0012_Write(pTuner, 0x0E, 0x80)) return -1;
if (FC0012_Write(pTuner, 0x0E, 0x00)) return -1;
- // VCO Re-Calibration if needed
+ // Read resulting VCO control voltage
if (FC0012_Write(pTuner, 0x0E, 0x00)) return -1;
if (FC0012_Read(pTuner, 0x0E, &read_byte)) return -1;
reg[14] = 0x3F & read_byte;
- if (VCO1)
+ // Adjust VCO range if control voltage is at the limit
+ if (VCO_band)
{
+ // high-band VCO hitting low frequency bound
if (reg[14] > 0x3C)
{
- reg[6] = 0x08 | reg[6];
+ // select low-band VCO
+ reg[6] = ~0x08 & reg[6];
if (FC0012_Write(pTuner, 0x06, reg[6])) return -1;
if (FC0012_Write(pTuner, 0x0E, 0x80)) return -1;
@@ -295,7 +310,9 @@ int FC0012_SetFrequency(void *pTuner, unsigned long Frequency,
unsigned short Ba
}
else
{
+ // low-band VCO hitting high frequency bound
if (reg[14] < 0x02) {
+ // select high-band VCO
reg[6] = 0x08 | reg[6];
if (FC0012_Write(pTuner, 0x06, reg[6])) return -1;
--
1.7.10