From d45aad4c74c73c327f0647e6c839d3c95ce63a02 Mon Sep 17 00:00:00 2001
From: Philipp Klaus <klaus@physik.uni-frankfurt.de>
Date: Thu, 13 Jul 2017 15:21:08 +0200
Subject: [PATCH] ADCuC: float output on USB w/ sprintf()

---
 atmega32u4/adcuc/Makefile |  2 +-
 atmega32u4/adcuc/main.c   | 24 +++++++++---------------
 2 files changed, 10 insertions(+), 16 deletions(-)

diff --git a/atmega32u4/adcuc/Makefile b/atmega32u4/adcuc/Makefile
index df1b1fc..3062ad7 100644
--- a/atmega32u4/adcuc/Makefile
+++ b/atmega32u4/adcuc/Makefile
@@ -37,7 +37,7 @@ CINCS =
 
 CDEBUG = -g$(DEBUG)
 CWARN = -Wall -Wstrict-prototypes 
-CTUNING = -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums  -Wl,--relax
+CTUNING = -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums  -Wl,--relax -Wl,-u,vfprintf -lprintf_flt -lm
 #CEXTRA = -Wa,-adhlns=$(<:.c=.lst)
 CFLAGS = $(CDEBUG) $(CDEFS) $(CINCS) -O$(OPT) $(CWARN) $(CSTANDARD) $(CEXTRA) $(CTUNING)
 
diff --git a/atmega32u4/adcuc/main.c b/atmega32u4/adcuc/main.c
index 491804b..039a67e 100644
--- a/atmega32u4/adcuc/main.c
+++ b/atmega32u4/adcuc/main.c
@@ -5,6 +5,7 @@
 #include <avr/io.h>
 #include <avr/eeprom.h>
 #include <string.h>
+#include <stdio.h>
 #include <usb_serial.h>
 
 #define FIRMWARE_VERSION 0x011
@@ -63,7 +64,7 @@ volatile uint16_t time = 0;
 
 uint8_t rxcnt = 0;
 uint8_t rxbuf[7];
-uint8_t txbuf[16];
+uint8_t txbuf[32];
 
 uint8_t conversion_active = 0;
 uint8_t channel = 0;
@@ -81,22 +82,13 @@ uint8_t hex_to_int(uint8_t h) { //assumes valid number
                 return h-0x61+10;
   }
 
-void send_answer_hex(uint8_t chan, uint16_t v) {
-  txbuf[0]='A';//ADC
-  txbuf[1]=nib_to_hex(chan,0);
-  txbuf[2]='-';//temperature or modi
-  txbuf[3]=nib_to_hex(v,3);
-  txbuf[4]=nib_to_hex(v,2);
-  txbuf[5]=nib_to_hex(v,1);
-  txbuf[6]=nib_to_hex(v,0);
-  txbuf[7]='\n';
-  txbuf[8] = 0;
-  usb_serial_write(txbuf,8);
+void send_answer(uint8_t chan, float v) {
+  int nbytes = sprintf(txbuf, "A%1d %.3f\n", chan, v);
+  usb_serial_write(txbuf, nbytes);
   usb_serial_flush_output();
   }
 
 
-
 ISR(TIMER0_OVF_vect) {
   time++;
   asm volatile("wdr");
@@ -119,8 +111,10 @@ void getdata(uint8_t buf) {
   }
 
 void original_value(uint8_t channel, uint8_t get_value_1, uint8_t get_value_2) {
-  uint16_t result = (get_value_1 << 8) | get_value_2;
-  send_answer_hex(channel+1,result);
+  uint16_t val = (get_value_1 << 8) | get_value_2;
+  float result = val;
+  result = result / 8.0 / 1000.;
+  send_answer(channel+1, result);
   }
 
 void update_eeprom(void) {
-- 
2.43.0