Diff: MAX11410.cpp

Revision:

26:298726bd5a3f

Parent:

25:c4be3afbfafd

Child:

27:1cb6c42c6a93

--- a/MAX11410.cpp	Thu Apr 16 22:18:10 2020 -0700
+++ b/MAX11410.cpp	Mon Apr 20 00:52:36 2020 +0000
@@ -884,6 +884,14 @@
                 SPIwrite16bits(mosiData16);
                 SPIoutputCS(1);
                 //
+                if (commandByte == CMD_r000_1110_00ss_0ggg_PGA)
+                {
+                    // update pgaGain with 1, 2, 4, 8, 16, 32, 64, or 128 based on gain index
+                    static uint8_t pgaGainTable[8] = {1, 2, 4, 8, 16, 32, 64, 128};
+                    pgaGain = (((regData >> 4) & 2) == SIG_PATH_10_PGA) 
+                        ? pgaGainTable[(uint8_t)(regData & 7)] 
+                        : 1;
+                }
                 if (commandByte == CMD_r000_0011_xxxx_xddd_CAL_START)
                 {
                     // after RegWrite CMD_r000_0011_xxxx_xddd_CAL_START, poll status until 0x000004 CAL_RDY
@@ -896,17 +904,25 @@
                     // A bad SPI interface can cause bit slippage, which makes this loop get stuck. Expect *PART_ID? = 0x000F02
                     // while ((status &  /* MAX11410_STATUS_enum_t:: */ STATUS_000010_DATA_RDY) == 0) {
                     // possible infinite loop; need a timeout or futility countdown to escape
-                    for (int futility_countdown = loop_limit;
-                        ((futility_countdown > 0) &&
-                        ((status &  /* MAX11410_STATUS_enum_t:: */ STATUS_000004_CAL_RDY) == 0));
-                        futility_countdown--)
+                    // with one exception: skip the wait loop in the corner case where
+                    // cal_start=1 and pga is either buffer, bypass, or GAIN_000_1 -- 
+                    // these are effectively 1V/V gain path, and since it's already handled
+                    // by self calibration, the pga calibration command behaves as a no-operation.
+                    if ((regData != 1) || (pgaGain != 1))
                     {
-                        for (int futility_countdown_inner = 32767;
-                            ((futility_countdown_inner > 0) &&
+                        // wait for CAL_RDY unless (cal_start=1 and pgaGain==1)
+                        for (int futility_countdown = loop_limit;
+                            ((futility_countdown > 0) &&
                             ((status &  /* MAX11410_STATUS_enum_t:: */ STATUS_000004_CAL_RDY) == 0));
-                            futility_countdown_inner--)
+                            futility_countdown--)
                         {
-                            RegRead(CMD_r011_1000_dddd_dddd_dddd_dddd_dxxx_dddd_STATUS, &status);
+                            for (int futility_countdown_inner = 32767;
+                                ((futility_countdown_inner > 0) &&
+                                ((status &  /* MAX11410_STATUS_enum_t:: */ STATUS_000004_CAL_RDY) == 0));
+                                futility_countdown_inner--)
+                            {
+                                RegRead(CMD_r011_1000_dddd_dddd_dddd_dddd_dxxx_dddd_STATUS, &status);
+                            }
                         }
                     }
                 }
@@ -1374,11 +1390,6 @@
 {
     
     //----------------------------------------
-    // pga gain 1, 2, 4, 8, 16, 32, 64, or 128 based on gain index in register pga CMD_r000_1110_00ss_0ggg_PGA
-    static uint8_t pgaGainTable[8] = {1, 2, 4, 8, 16, 32, 64, 128};
-    pgaGain = (sigpath == SIG_PATH_10_PGA) ? pgaGainTable[(uint8_t)gain] : 1;
-    
-    //----------------------------------------
     // write8 0x0E PGA
     RegWrite(CMD_r000_1110_00ss_0ggg_PGA, (uint8_t)(0
         | (((uint8_t)sigpath & 2) << 4)