allow arbitrary value input

git-svn-id: https://bucket.mit.edu/svn/nilm/zoom@7173 ddd99763-3ecb-0310-9145-efcb8ce7c51f

firmware/util.c

@@ -25,3 +25,20 @@ uint8_t from_hex(uint8_t ch)
 const uint8_t hex[16]={'0','1','2','3','4','5','6','7',
 		       '8','9','a','b','c','d','e','f'};
 
+/* Convert 4 ASCII hex digits into a 16-bit unsigned number.
+   Returns the number, or -1 if there's an error */
+int32_t hex_to_u16(char x[4])
+{
+	uint16_t v = 0;
+	uint8_t t;
+	int i;
+
+	for (i = 0; i < 4; i++) {
+		t = from_hex(x[i]);
+		if (t >= 16)
+			return -1;
+		v = (v << 4) | t;
+	}
+	return v;
+}
+

firmware/util.h

@@ -6,6 +6,7 @@
 /* Convert from ascii hex digit to number */
 uint8_t from_hex(uint8_t ch);
 extern const uint8_t hex[16];
+int32_t hex_to_u16(char x[4])
 
 /* Array length */
 #define array_len(x) (sizeof(x)/sizeof(x[0]))

firmware/zoom.c

@@ -94,6 +94,8 @@ void run_debug(void)
 {
 	uint16_t dac = 32768;
 	int16_t adc;
+	int32_t v;
+	char buf[4];
 	uart1_init(115200);	
 
 	uart1_put_string("Zoom NILM Debug\r\n");
@@ -101,10 +103,10 @@ void run_debug(void)
 	while (1) {
 		dac_write(dac);
 		uart1_put_dec(dac);
-	    uart1_put(' ');
+		uart1_put(' ');
 		adc = adc_get();
 		uart1_put_hex16(adc);
-	    uart1_put(' ');
+		uart1_put(' ');
 		uart1_put_dec(adc);
 		uart1_crlf();
 		switch (uart1_get()) {
@@ -138,6 +140,18 @@ void run_debug(void)
 			uart1_crlf();
 			dac = 32768;
 			break;
+		case 'v':
+		case 'V':
+			buf[0] = uart1_get();
+			buf[1] = uart1_get();
+			buf[2] = uart1_get();
+			buf[3] = uart1_get();
+			v = hex_to_u16(buf);
+			if (v < 0)
+				uart1_put_string("bad value\r\n");
+			else
+				dac = v;
+			break;
 		}
 	}
 }