turn output off when switching attenuator ranges

2 files changed, 21 insertions, 6 deletions

diff --git a/device-functions.c b/device-functions.c
index f79017c..ac4a9b4 100644
--- a/device-functions.c
+++ b/device-functions.c
@@ -316,22 +316,37 @@ int Set_Amplitude(int check_possible_only,int pol_override,int override_on,int w
 		}
 
 		// Are attenuators used?
+		int atten_ctl = 0;
+
 		if (attenuator_count(channel) == 1) {
 			// deal with attenuator range - haven't done for CH2 yet
 
 			if (atten_range == 0) {
-				set_shiftreg_bits(SR_2, XTR_POS + 1, ONE_BIT, BIT_HIGH);
+				atten_ctl = BIT_HIGH;
 			} else {
-				set_shiftreg_bits(SR_2, XTR_POS + 1, ONE_BIT, BIT_LOW);
+				atten_ctl = BIT_LOW;
 			}
+
+			set_shiftreg_bits(SR_2, XTR_POS + 1, ONE_BIT, atten_ctl);
+
 		} else if (attenuator_count(channel) > 1) {
 
 			// octal relay driver is inverted
 			if ((atten_range < 0) || (atten_range >= max_attens)) {
-				I2C_Write(PCF8574+Octal_Relay_Driver,0xff);
+				atten_ctl = 0xff;
 			} else {
-				int atten_ctl = ~((1 << (atten_range+1)) - 1);
-				I2C_Write(PCF8574+Octal_Relay_Driver, atten_ctl);
+				atten_ctl = ~((1 << (atten_range+1)) - 1);
+			}
+
+			I2C_Write(PCF8574+Octal_Relay_Driver, atten_ctl);
+		}
+
+		if (	(globals.Registers.last_relay_driver_settings[3] != atten_ctl)) {
+
+			globals.Registers.last_relay_driver_settings[3] = atten_ctl;
+
+			if (globals.ChannelState[channel].output_state==output_on) {
+				globals.Flags.force_output_fully_off=YES;
 			}
 		}
 
diff --git a/globals.h b/globals.h
index ac73e5d..fd8bb06 100644
--- a/globals.h
+++ b/globals.h
@@ -281,7 +281,7 @@ unsigned long long ms_timer (void);
 typedef struct {
 	int parallel_DAC_reg[8];
 	long shift_reg_out[num_out_SRs];
-	long last_relay_driver_settings[3];
+	long last_relay_driver_settings[4];
 	int oper_enable_register;       /* for stat:enable command */
 	int ques_enable_register;       /* for stat:enable command */
 	int avrq_reg;