diff --git a/buspirate_spi.c b/buspirate_spi.c
index ae939e3..39b9c52 100644
--- a/buspirate_spi.c
+++ b/buspirate_spi.c
@@ -228,6 +228,7 @@
 	int serialspeed_index = -1;
 	int ret = 0;
 	int pullup = 0;
+	int psu = 0;
 
 	dev = extract_programmer_param("dev");
 	if (dev && !strlen(dev)) {
@@ -277,6 +278,17 @@
 	}
 	free(tmp);
 
+	tmp = extract_programmer_param("psus");
+	if (tmp) {
+		if (strcasecmp("on", tmp) == 0)
+			psu = 1;
+		else if (strcasecmp("off", tmp) == 0)
+			; // ignore
+		else
+			msg_perr("Invalid psus state, not enabling.\n");
+	}
+	free(tmp);
+
 	/* Default buffer size is 19: 16 bytes data, 3 bytes control. */
 #define DEFAULT_BUFSIZE (16 + 3)
 	bp_commbuf = malloc(DEFAULT_BUFSIZE);
@@ -527,6 +539,10 @@
 		bp_commbuf[0] |= (1 << 2);
 		msg_pdbg("Enabling pull-up resistors.\n");
 	}
+	if (psu == 1) {
+		bp_commbuf[0] |= (1 << 3);
+		msg_pdbg("Enabling PSUs.\n");
+	}
 	ret = buspirate_sendrecv(bp_commbuf, 1, 1);
 	if (ret) {
 		ret = 1;