diff --git a/F3:F303/MLX90640-allsky/allsky.bin b/F3:F303/MLX90640-allsky/allsky.bin
index 2ad859f..b8a8e40 100755
Binary files a/F3:F303/MLX90640-allsky/allsky.bin and b/F3:F303/MLX90640-allsky/allsky.bin differ
diff --git a/F3:F303/MLX90640-allsky/i2c.c b/F3:F303/MLX90640-allsky/i2c.c
index 32a115a..a6e822b 100644
--- a/F3:F303/MLX90640-allsky/i2c.c
+++ b/F3:F303/MLX90640-allsky/i2c.c
@@ -20,8 +20,6 @@
 #include <string.h>
 
 #include "i2c.h"
-#include "strfunc.h" // hexdump
-#include "usb_dev.h"
 
 i2c_speed_t i2c_curspeed = I2C_SPEED_AMOUNT;
 extern volatile uint32_t Tms;
@@ -45,7 +43,8 @@ static uint8_t dmaaddr = 0; // address to continuous read by DMA
 static inline int isI2Cbusy(){
     cntr = Tms;
     do{
-        if(Tms - cntr > I2C_TIMEOUT){ USND("Timeout, DMA transfer in progress?"); return 1;}
+        IWDG->KR = IWDG_REFRESH;
+        if(Tms - cntr > I2C_TIMEOUT) return 1;
     }while(I2Cbusy);
     return 0;
 }
@@ -90,7 +89,6 @@ void i2c_setup(i2c_speed_t speed){
             SCLL = 0x2;
         break;
         default:
-            USND("Wrong I2C speed!");
             return; // wrong speed
     }
     RCC->AHBENR |= RCC_AHBENR_GPIOBEN;
@@ -318,21 +316,8 @@ int i2c_scan_next_addr(uint8_t *addr){
     return 1;
 }
 
-// dump I2Cbuf
-void i2c_bufdudump(){
-    if(goterr){
-        USND("DMARDERR");
-        goterr = 0;
-    }
-    if(i2cbuflen < 1) return;
-    USND("DMARD=");
-    hexdump16(USB_sendstr, (uint16_t*)I2Cbuf, i2cbuflen);
-}
-
 // get DMA buffer with conversion to little-endian (if transfer was for 16-bit)
 uint16_t *i2c_dma_getbuf(uint16_t *len){
-    //if(i2c_got_DMA) USND("DMA GOT!");
-    //U("T="); U(u2str(Tms)); U("; cndtr: "); USND(u2str(DMA1_Channel7->CNDTR));
     if(!i2c_got_DMA || i2cbuflen < 1) return NULL;
     i2c_got_DMA = 0;
     i2cbuflen >>= 1; // for hexdump16 - now buffer have uint16_t!
diff --git a/F3:F303/MLX90640-allsky/i2c.h b/F3:F303/MLX90640-allsky/i2c.h
index f525880..5715a82 100644
--- a/F3:F303/MLX90640-allsky/i2c.h
+++ b/F3:F303/MLX90640-allsky/i2c.h
@@ -48,7 +48,6 @@ uint16_t *i2c_read_reg16(uint8_t addr, uint16_t reg16, uint16_t nwords, uint8_t
 uint8_t i2c_write(uint8_t addr, uint16_t *data, uint8_t nwords);
 uint8_t i2c_write_dma16(uint8_t addr, uint16_t *data, uint8_t nwords);
 
-void i2c_bufdudump();
 int i2c_dma_haderr();
 uint16_t *i2c_dma_getbuf(uint16_t *len);
 int i2c_getwords(uint16_t *buf, int bufsz);
diff --git a/F3:F303/MLX90640-allsky/ir-allsky.creator.user b/F3:F303/MLX90640-allsky/ir-allsky.creator.user
index 65f6698..bc2d899 100644
--- a/F3:F303/MLX90640-allsky/ir-allsky.creator.user
+++ b/F3:F303/MLX90640-allsky/ir-allsky.creator.user
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE QtCreatorProject>
-<!-- Written by QtCreator 17.0.1, 2025-09-28T20:36:21. -->
+<!-- Written by QtCreator 17.0.1, 2025-09-29T22:10:22. -->
 <qtcreator>
  <data>
   <variable>EnvironmentId</variable>
diff --git a/F3:F303/MLX90640-allsky/main.c b/F3:F303/MLX90640-allsky/main.c
index e4fc63c..c2fc250 100644
--- a/F3:F303/MLX90640-allsky/main.c
+++ b/F3:F303/MLX90640-allsky/main.c
@@ -32,6 +32,8 @@ void sys_tick_handler(void){
     ++Tms;
 }
 
+const char *scanend = "SCANEND\n", *foundid = "FOUNDID=";
+
 int main(void){
     char inbuff[MAXSTRLEN+1];
     if(StartHSE()){
@@ -58,33 +60,40 @@ int main(void){
         int l = USB_receivestr(inbuff, MAXSTRLEN);
         if(l < 0) USB_sendstr("USBOVERFLOW\n");
         else if(l){
-            const char *ans = parse_cmd(inbuff);
+            const char *ans = parse_cmd(inbuff, SEND_USB);
             if(ans) USB_sendstr(ans);
         }
-        if(i2c_scanmode){
+        if(i2c_scanmode){ // send this to both
             uint8_t addr;
             int ok = i2c_scan_next_addr(&addr);
-            if(addr == I2C_ADDREND) USND("SCANEND");
-            else if(ok){
-                U("FOUNDID=");
-                USND(uhex2str(addr));
+            if(addr == I2C_ADDREND){
+                USB_sendstr(scanend); USB_putbyte('\n');
+                usart_sendstr(scanend); usart_putbyte('\n');
+            }else if(ok){
+                const char *straddr = uhex2str(addr);
+                USB_sendstr(foundid); USB_sendstr(straddr); USB_putbyte('\n');
+                usart_sendstr(foundid); usart_sendstr(straddr); usart_putbyte('\n');
             }
         }
         mlx_process();
-        if(cartoon) for(int i = 0; i < N_SESORS; ++i){
+        if(cartoon) for(int i = 0; i < N_SESORS; ++i){ // USB-only
             uint32_t Tnow = mlx_lastimT(i);
             if(Tnow != Tlastima[i]){
                 fp_t *im = mlx_getimage(i);
                 if(im){
-                    U(Sensno); USND(i2str(i));
-                    U(Timage); USND(u2str(Tnow)); drawIma(im);
+                    chsendfun(SEND_USB);
+                    U(Sensno); UN(i2str(i));
+                    U(Timage); UN(u2str(Tnow)); drawIma(im);
                     Tlastima[i] = Tnow;
                 }
             }
         }
         usart_process();
-        if(usart_ovr()) USND("USART_OVERFLOW\n");
+        if(usart_ovr()) usart_sendstr("USART_OVERFLOW\n");
         char *got = usart_getline(NULL);
-        if(got){ U("USART='"); U(got); USND("'"); }
+        if(got){
+            const char *ans = parse_cmd(got, SEND_USART);
+            if(ans) usart_sendstr(ans);
+        }
     }
 }
diff --git a/F3:F303/MLX90640-allsky/mlx90640.c b/F3:F303/MLX90640-allsky/mlx90640.c
index 7b974af..73b3a76 100644
--- a/F3:F303/MLX90640-allsky/mlx90640.c
+++ b/F3:F303/MLX90640-allsky/mlx90640.c
@@ -34,52 +34,6 @@ static fp_t mlx_image[MLX_PIXNO] = {0}; // ready image
 // 10100 bytes:
 static MLX90640_params params; // calculated parameters (in heap, not stack!) for other functions
 
-void dumpIma(const fp_t im[MLX_PIXNO]){
-    for(int row = 0; row < MLX_H; ++row){
-        for(int col = 0; col < MLX_W; ++col){
-            printfl(*im++, 1);
-            USB_putbyte(' ');
-        }
-        newline();
-    }
-}
-
-#define GRAY_LEVELS     (16)
-// 16-level character set ordered by fill percentage (provided by user)
-static const char* CHARS_16 = " .':;+*oxX#&%B$@";
-void drawIma(const fp_t im[MLX_PIXNO]){
-    // Find min and max values
-    fp_t min_val = im[0], max_val = im[0];
-    const fp_t *iptr = im;
-    for(int row = 0; row < MLX_H; ++row){
-        for(int col = 0; col < MLX_W; ++col){
-            fp_t cur = *iptr++;
-            if(cur < min_val) min_val = cur;
-            else if(cur > max_val) max_val = cur;
-        }
-    }
-    fp_t range = max_val - min_val;
-    U("RANGE="); USND(float2str(range, 3));
-    U("MIN="); USND(float2str(min_val, 3));
-    U("MAX="); USND(float2str(max_val, 3));
-    if(fabsf(range) < 0.001) range = 1.; // solid fill -> blank
-    // Generate and print ASCII art
-    iptr = im;
-    for(int row = 0; row < MLX_H; ++row){
-        for(int col = 0; col < MLX_W; ++col){
-            fp_t normalized = ((*iptr++) - min_val) / range;
-            // Map to character index (0 to 15)
-            int index = (int)(normalized * GRAY_LEVELS);
-            // Ensure we stay within bounds
-            if(index < 0) index = 0;
-            else if(index > (GRAY_LEVELS-1)) index = (GRAY_LEVELS-1);
-            USB_putbyte(CHARS_16[index]);
-        }
-        newline();
-    }
-    newline();
-}
-
 /*****************************************************************************
                 Calculate parameters & values
  *****************************************************************************/
@@ -109,7 +63,7 @@ MLX90640_params *get_parameters(const uint16_t dataarray[MLX_DMA_MAXLEN]){
     uint16_t val = CREG_VAL(REG_VDD);
     i8 = (int8_t) (val >> 8);
     params.kVdd = i8 * 32; // keep sign
-    if(params.kVdd == 0){USND("kvdd=0"); return NULL;}
+    if(params.kVdd == 0){UN("kvdd=0"); return NULL;}
     i16 = val & 0xFF;
     params.vdd25 = ((i16 - 0x100) * 32) - (1<<13);
     val = CREG_VAL(REG_KVTPTAT);
@@ -123,7 +77,7 @@ MLX90640_params *get_parameters(const uint16_t dataarray[MLX_DMA_MAXLEN]){
     val = CREG_VAL(REG_APTATOCCS) >> 12;
     params.alphaPTAT = val / 4. + 8.;
     params.gainEE = (int16_t)CREG_VAL(REG_GAIN);
-    if(params.gainEE == 0){USND("gainee=0"); return NULL;}
+    if(params.gainEE == 0){UN("gainee=0"); return NULL;}
     int8_t occRow[MLX_H];
     int8_t occColumn[MLX_W];
     occacc(occRow, MLX_H, &CREG_VAL(REG_OCCROW14));
@@ -151,7 +105,7 @@ MLX90640_params *get_parameters(const uint16_t dataarray[MLX_DMA_MAXLEN]){
     // so index of ktaavg is 2*(row&1)+(col&1)
     val = CREG_VAL(REG_KTAVSCALE);
     uint8_t scale1 = ((val & 0xFF)>>4) + 8, scale2 = (val&0xF);
-    if(scale1 == 0 || scale2 == 0){USND("scale1/2=0"); return NULL;}
+    if(scale1 == 0 || scale2 == 0){UN("scale1/2=0"); return NULL;}
     fp_t mul = (fp_t)(1<<scale2), div = (fp_t)(1<<scale1); // kta_scales
     uint16_t a_r = CREG_VAL(REG_SENSIVITY); // alpha_ref
     val = CREG_VAL(REG_SCALEACC);
@@ -271,10 +225,10 @@ fp_t *process_image(const int16_t subpage1[REG_IMAGEDATA_LEN]){
     fp_t dvdd, dTa, Kgain, pixOS[2]; // values for both subpages
     // 11.2.2.2. Supply voltage value calculation
     i16a = (int16_t)IMD_VAL(REG_IVDDPIX);
-    //U("rval="); USND(i2str(i16a));
+    //U("rval="); UN(i2str(i16a));
     dvdd = resol_corr*i16a - params.vdd25;
     dvdd /= params.kVdd;
-    //U("dvdd="); USND(float2str(dvdd, 2));
+    //U("dvdd="); UN(float2str(dvdd, 2));
     fp_t dV = i16a - params.vdd25; // for next step
     dV /= params.kVdd;
     // 11.2.2.3. Ambient temperature calculation
diff --git a/F3:F303/MLX90640-allsky/mlx90640.h b/F3:F303/MLX90640-allsky/mlx90640.h
index 27a5308..355dffc 100644
--- a/F3:F303/MLX90640-allsky/mlx90640.h
+++ b/F3:F303/MLX90640-allsky/mlx90640.h
@@ -60,5 +60,3 @@ typedef struct{
 int ch_resolution(uint8_t newresol);
 MLX90640_params *get_parameters(const uint16_t dataarray[MLX_DMA_MAXLEN]);
 fp_t *process_image(const int16_t subpage1[REG_IMAGEDATA_LEN]);
-void dumpIma(const fp_t im[MLX_PIXNO]);
-void drawIma(const fp_t im[MLX_PIXNO]);
diff --git a/F3:F303/MLX90640-allsky/mlxproc.c b/F3:F303/MLX90640-allsky/mlxproc.c
index d44ce5c..1c36866 100644
--- a/F3:F303/MLX90640-allsky/mlxproc.c
+++ b/F3:F303/MLX90640-allsky/mlxproc.c
@@ -28,7 +28,7 @@
 #include "usb_dev.h"
 #include "strfunc.h"
 #define D(x)        U(x)
-#define DN(x)       USND(x)
+#define DN(x)       UN(x)
 #define DB(x)       USB_putbute(x)
 #else
 #define D(x)
diff --git a/F3:F303/MLX90640-allsky/proto.c b/F3:F303/MLX90640-allsky/proto.c
index 7857960..2805c6a 100644
--- a/F3:F303/MLX90640-allsky/proto.c
+++ b/F3:F303/MLX90640-allsky/proto.c
@@ -16,11 +16,13 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <math.h>
 #include <stm32f3.h>
 #include <string.h>
 
 #include "i2c.h"
 #include "mlxproc.h"
+#include "proto.h"
 #include "strfunc.h"
 #include "usart.h"
 #include "usb_dev.h"
@@ -33,6 +35,34 @@ static uint8_t I2Caddress = 0x33 << 1;
 extern volatile uint32_t Tms;
 uint8_t cartoon = 0; // "cartoon" mode: refresh image each time we get new
 
+// functions to send data over USB or USART: to change them use flag in `parse_cmd`
+typedef struct{
+    int (*S)(const char*);          // send string
+    int (*P)(uint8_t);              // put byte
+    int (*B)(const uint8_t*, int);  // send raw bytes
+} sendfun_t;
+
+static sendfun_t usbsend = {
+    .S = USB_sendstr, .P = USB_putbyte, .B = USB_send
+};
+static sendfun_t usartsend = {
+    .S = usart_sendstr, .P = usart_putbyte, .B = usart_send
+};
+
+static sendfun_t *sendfun = &usbsend;
+
+void chsendfun(int sendto){
+    if(sendto == SEND_USB) sendfun = &usbsend;
+    else sendfun = &usartsend;
+}
+
+// newline
+#define N() sendfun->P('\n')
+#define printu(x)       do{sendfun->S(u2str(x));}while(0)
+#define printi(x)       do{sendfun->S(i2str(x));}while(0)
+#define printuhex(x)    do{sendfun->S(uhex2str(x));}while(0)
+#define printfl(x,n)    do{sendfun->S(float2str(x, n));}while(0)
+
 // common names for frequent keys
 const char *Timage = "TIMAGE=";
 const char *Sensno = "SENSNO=";
@@ -47,11 +77,11 @@ const char *helpstring =
         "gn - get nth image 'as is' - float array of 768x4 bytes\n"
         "i0..4 - setup I2C with speed 10k, 100k, 400k, 1M or 2M (experimental!)\n"
         "l - list active sensors IDs\n"
-        "tn - show temperature map of nth image\n"
+        "mn - show temperature map of nth image\n"
         "p - pause MLX\n"
-        "s - stop MLX (and start from zero @ 'c'\n"
+        "s - stop MLX (and start from zero @ 'c')\n"
         "tn - show nth image aquisition time\n"
-        "C - \"cartoon\" mode on/off (show each new image)\n"
+        "C - \"cartoon\" mode on/off (show each new image) - USB only!!!\n"
         "Dn - dump MLX parameters for sensor number n\n"
         "G - get MLX state\n"
         "Ia addr [n] - set  device address for interactive work or (with n) change address of n'th sensor\n"
@@ -59,7 +89,7 @@ const char *helpstring =
         "Iw words - send words (hex/dec/oct/bin) to I2C\n"
         "Is - scan I2C bus\n"
         "T - print current Tms\n"
-        "Us - send string 's' to USART\n"
+        "Us - send string 's' to other interface\n"
 ;
 
 TRUE_INLINE const char *setupI2C(char *buf){
@@ -78,7 +108,7 @@ TRUE_INLINE const char *setupI2C(char *buf){
         }
         i2c_setup((i2c_speed_t)speed);
     }
-    U("I2CSPEED="); USND(speeds[i2c_curspeed]);
+    sendfun->S("I2CSPEED="); sendfun->S(speeds[i2c_curspeed]); N();
     return NULL;
 }
 
@@ -89,11 +119,11 @@ TRUE_INLINE const char *chhwaddr(const char *buf){
         if(nxt && nxt != buf){
             if(!mlx_sethwaddr(I2Caddress, a)) return ERR;
         }else{
-            USND("Wrong number");
+            sendfun->S("Wrong number"); N();
             return ERR;
         }
     }else{
-        USND("Need address");
+        sendfun->S("Need address"); N();
         return ERR;
     }
     return OK;
@@ -117,7 +147,7 @@ TRUE_INLINE const char *chaddr(const char *buf){
         int n = getsensnum(nxt);
         if(n > -1) mlx_setaddr(n, addr);
     }else addr = I2Caddress >> 1;
-    U("I2CADDR="); USND(uhex2str(addr));
+    sendfun->S("I2CADDR="); sendfun->S(uhex2str(addr)); N();
     return NULL;
 }
 
@@ -135,8 +165,8 @@ static const char *rdI2C(const char *buf){
         char b[5];
         u16s(*b16, b);
         b[4] = 0;
-        USND(b);
-    }else hexdump16(USB_sendstr, b16, N);
+        sendfun->S(b); N();
+    }else hexdump16(sendfun->S, b16, N);
     return NULL;
 }
 
@@ -156,7 +186,8 @@ static const char *wrI2C(const char *buf){
     uint16_t N = readNnumbers(buf);
     if(N == 0) return ERR;
     for(int i = 0; i < N; ++i){
-        U("byte "); U(u2str(i)); U(" :"); USND(uhex2str(locBuffer[i]));
+        sendfun->S("byte "); sendfun->S(u2str(i));
+        sendfun->S(" :"); sendfun->S(uhex2str(locBuffer[i])); N();
     }
     if(!i2c_write(I2Caddress, locBuffer, N)) return ERR;
     return OK;
@@ -165,58 +196,58 @@ static const char *wrI2C(const char *buf){
 static void dumpfarr(float *arr){
     for(int row = 0; row < 24; ++row){
         for(int col = 0; col < 32; ++col){
-            printfl(*arr++, 2); USB_putbyte(' ');
+            printfl(*arr++, 2); sendfun->P(' ');
         }
-        newline();
+        N();
     }
 }
 // dump MLX parameters
 TRUE_INLINE void dumpparams(const char *buf){
     int N = getsensnum(buf);
-    if(N < 0){ U(ERR); return; }
+    if(N < 0){ sendfun->S(ERR); return; }
     MLX90640_params *params = mlx_getparams(N);
-    if(!params){ U(ERR); return; }
-    U(Sensno); USND(i2str(N));
-    U("\nkVdd="); printi(params->kVdd);
-    U("\nvdd25="); printi(params->vdd25);
-    U("\nKvPTAT="); printfl(params->KvPTAT, 4);
-    U("\nKtPTAT="); printfl(params->KtPTAT, 4);
-    U("\nvPTAT25="); printi(params->vPTAT25);
-    U("\nalphaPTAT="); printfl(params->alphaPTAT, 2);
-    U("\ngainEE="); printi(params->gainEE);
-    U("\nPixel offset parameters:\n");
+    if(!params){ sendfun->S(ERR); return; }
+    sendfun->S(Sensno); sendfun->S(i2str(N)); N();
+    sendfun->S("\nkVdd="); printi(params->kVdd);
+    sendfun->S("\nvdd25="); printi(params->vdd25);
+    sendfun->S("\nKvPTAT="); printfl(params->KvPTAT, 4);
+    sendfun->S("\nKtPTAT="); printfl(params->KtPTAT, 4);
+    sendfun->S("\nvPTAT25="); printi(params->vPTAT25);
+    sendfun->S("\nalphaPTAT="); printfl(params->alphaPTAT, 2);
+    sendfun->S("\ngainEE="); printi(params->gainEE);
+    sendfun->S("\nPixel offset parameters:\n");
     float *offset = params->offset;
     for(int row = 0; row < 24; ++row){
         for(int col = 0; col < 32; ++col){
-            printfl(*offset++, 2); USB_putbyte(' ');
+            printfl(*offset++, 2); sendfun->P(' ');
         }
-        newline();
+        N();
     }
-    U("K_talpha:\n");
+    sendfun->S("K_talpha:\n");
     dumpfarr(params->kta);
-    U("Kv: ");
+    sendfun->S("Kv: ");
     for(int i = 0; i < 4; ++i){
-        printfl(params->kv[i], 2); USB_putbyte(' ');
+        printfl(params->kv[i], 2); sendfun->P(' ');
     }
-    U("\ncpOffset=");
-    printi(params->cpOffset[0]); U(", "); printi(params->cpOffset[1]);
-    U("\ncpKta="); printfl(params->cpKta, 2);
-    U("\ncpKv="); printfl(params->cpKv, 2);
-    U("\ntgc="); printfl(params->tgc, 2);
-    U("\ncpALpha="); printfl(params->cpAlpha[0], 2);
-    U(", "); printfl(params->cpAlpha[1], 2);
-    U("\nKsTa="); printfl(params->KsTa, 2);
-    U("\nAlpha:\n");
+    sendfun->S("\ncpOffset=");
+    printi(params->cpOffset[0]); sendfun->S(", "); printi(params->cpOffset[1]);
+    sendfun->S("\ncpKta="); printfl(params->cpKta, 2);
+    sendfun->S("\ncpKv="); printfl(params->cpKv, 2);
+    sendfun->S("\ntgc="); printfl(params->tgc, 2);
+    sendfun->S("\ncpALpha="); printfl(params->cpAlpha[0], 2);
+    sendfun->S(", "); printfl(params->cpAlpha[1], 2);
+    sendfun->S("\nKsTa="); printfl(params->KsTa, 2);
+    sendfun->S("\nAlpha:\n");
     dumpfarr(params->alpha);
-    U("\nCT3="); printfl(params->CT[1], 2);
-    U("\nCT4="); printfl(params->CT[2], 2);
+    sendfun->S("\nCT3="); printfl(params->CT[1], 2);
+    sendfun->S("\nCT4="); printfl(params->CT[2], 2);
     for(int i = 0; i < 4; ++i){
-        U("\nKsTo"); USB_putbyte('0'+i); USB_putbyte('=');
+        sendfun->S("\nKsTo"); sendfun->P('0'+i); sendfun->P('=');
         printfl(params->KsTo[i], 2);
-        U("\nalphacorr"); USB_putbyte('0'+i); USB_putbyte('=');
+        sendfun->S("\nalphacorr"); sendfun->P('0'+i); sendfun->P('=');
         printfl(params->alphacorr[i], 2);
     }
-    newline();
+    N();
 }
 // get MLX state
 TRUE_INLINE void getst(){
@@ -228,8 +259,8 @@ TRUE_INLINE void getst(){
         [MLX_RELAX] = "do nothing"
     };
     mlx_state_t s = mlx_state();
-    U("MLXSTATE=");
-    USND(states[s]);
+    sendfun->S("MLXSTATE=");
+    sendfun->S(states[s]); N();
 }
 
 // `draw`==1 - draw, ==0 - show T map, 2 - send raw float array with prefix 'SENSNO=x\nTimage=y\n' and postfix "ENDIMAGE\n"
@@ -239,8 +270,8 @@ static const char *drawimg(const char *buf, int draw){
         uint32_t T = mlx_lastimT(sensno);
         fp_t *img = mlx_getimage(sensno);
         if(img){
-            U(Sensno); USND(u2str(sensno));
-            U(Timage); USND(u2str(T));
+            sendfun->S(Sensno); sendfun->S(u2str(sensno)); N();
+            sendfun->S(Timage); sendfun->S(u2str(T)); N();
             switch(draw){
                 case 0:
                     dumpIma(img);
@@ -255,12 +286,12 @@ static const char *drawimg(const char *buf, int draw){
                     // send by portions of 256 bytes (as image is larger than ringbuffer)
                     while(_2send){
                         uint32_t portion = (_2send > 256) ? 256 : _2send;
-                        USB_send(d, portion);
+                        sendfun->B(d, portion);
                         _2send -= portion;
                         d += portion;
                     }
                 }
-                    USND("ENDIMAGE");
+                    sendfun->S("ENDIMAGE"); N();
             }
             return NULL;
         }
@@ -270,26 +301,35 @@ static const char *drawimg(const char *buf, int draw){
 
 TRUE_INLINE void listactive(){
     int N =  mlx_nactive();
-    if(!N){ USND("No active sensors found!"); return; }
+    if(!N){ sendfun->S("No active sensors found!\n"); return; }
     uint8_t *ids = mlx_activeids();
-    U("Found "); USB_putbyte('0'+N); USND(" active sensors:");
+    sendfun->S("Found "); sendfun->P('0'+N);
+    sendfun->S(" active sensors:"); N();
     for(int i = 0; i < N_SESORS; ++i)
         if(ids[i]){
-            U("SENSID"); U(u2str(i)); USB_putbyte('=');
-            U(uhex2str(ids[i] >> 1));
-            newline();
+            sendfun->S("SENSID");
+            sendfun->S(u2str(i)); sendfun->P('=');
+            sendfun->S(uhex2str(ids[i] >> 1));
+            N();
         }
 }
 
 static void getimt(const char *buf){
     int sensno = getsensnum(buf);
     if(sensno > -1){
-        U(Timage); USND(u2str(mlx_lastimT(sensno)));
-    }else U(ERR);
+        sendfun->S(Timage); sendfun->S(u2str(mlx_lastimT(sensno))); N();
+    }else sendfun->S(ERR);
 }
 
-const char *parse_cmd(char *buf){
+/**
+ * @brief parse_cmd - user string parser
+ * @param buf - user data
+ * @param isusb - ==1 to send answer over usb, else send over USART1
+ * @return answer OK/ERR or NULL
+ */
+const char *parse_cmd(char *buf, int sendto){
     if(!buf || !*buf) return NULL;
+    chsendfun(sendto);
     if(buf[1]){
         switch(*buf){ // "long" commands
             case 'a':
@@ -325,7 +365,9 @@ const char *parse_cmd(char *buf){
                 }
                 break;
             case 'U':
-                if(usart_sendstr(buf + 1) && usart_putchar('\n')) return OK;
+                if(sendto == SEND_USB) chsendfun(SEND_USART);
+                else chsendfun(SEND_USB);
+                if(sendfun->S(buf + 1) && N()) return OK;
                 return ERR;
             default:
                 return ERR;
@@ -345,18 +387,18 @@ const char *parse_cmd(char *buf){
         case 's':
             mlx_stop(); return OK;
         case 'C':
+            if(sendto != SEND_USB) return ERR;
             cartoon = !cartoon; return OK;
         case 'G':
             getst();
         break;
         case 'T':
-            U("T=");
-            USND(u2str(Tms));
+            sendfun->S("T="); sendfun->S(u2str(Tms)); N();
         break;
         case '?': // help
         case 'h':
         case 'H':
-            U(helpstring);
+            sendfun->S(helpstring);
         break;
         default:
             return ERR;
@@ -364,3 +406,52 @@ const char *parse_cmd(char *buf){
     }
     return NULL;
 }
+
+// dump image as temperature matrix
+void dumpIma(const fp_t im[MLX_PIXNO]){
+    for(int row = 0; row < MLX_H; ++row){
+        for(int col = 0; col < MLX_W; ++col){
+            printfl(*im++, 1);
+            sendfun->P(' ');
+        }
+        N();
+    }
+}
+
+#define GRAY_LEVELS     (16)
+// 16-level character set ordered by fill percentage (provided by user)
+static const char* CHARS_16 = " .':;+*oxX#&%B$@";
+// draw image in ASCII-art
+void drawIma(const fp_t im[MLX_PIXNO]){
+    // Find min and max values
+    fp_t min_val = im[0], max_val = im[0];
+    const fp_t *iptr = im;
+    for(int row = 0; row < MLX_H; ++row){
+        for(int col = 0; col < MLX_W; ++col){
+            fp_t cur = *iptr++;
+            if(cur < min_val) min_val = cur;
+            else if(cur > max_val) max_val = cur;
+        }
+    }
+    fp_t range = max_val - min_val;
+    sendfun->S("RANGE="); sendfun->S(float2str(range, 3));
+    sendfun->S("\nMIN="); sendfun->S(float2str(min_val, 3));
+    sendfun->S("\nMAX="); sendfun->S(float2str(max_val, 3)); N();
+    if(fabsf(range) < 0.001) range = 1.; // solid fill -> blank
+    // Generate and print ASCII art
+    iptr = im;
+    for(int row = 0; row < MLX_H; ++row){
+        for(int col = 0; col < MLX_W; ++col){
+            fp_t normalized = ((*iptr++) - min_val) / range;
+            // Map to character index (0 to 15)
+            int index = (int)(normalized * GRAY_LEVELS);
+            // Ensure we stay within bounds
+            if(index < 0) index = 0;
+            else if(index > (GRAY_LEVELS-1)) index = (GRAY_LEVELS-1);
+            sendfun->P(CHARS_16[index]);
+        }
+        N();
+    }
+    N();
+}
+
diff --git a/F3:F303/MLX90640-allsky/proto.h b/F3:F303/MLX90640-allsky/proto.h
index c65b78d..398ba7a 100644
--- a/F3:F303/MLX90640-allsky/proto.h
+++ b/F3:F303/MLX90640-allsky/proto.h
@@ -20,5 +20,11 @@
 
 extern const char *Timage, *Sensno;
 
+#define SEND_USB    (1)
+#define SEND_USART  (0)
+
 extern uint8_t cartoon;
-char *parse_cmd(char *buf);
+void chsendfun(int sendto);
+const char *parse_cmd(char *buf, int sendto);
+void dumpIma(const fp_t im[MLX_PIXNO]);
+void drawIma(const fp_t im[MLX_PIXNO]);
diff --git a/F3:F303/MLX90640-allsky/strfunc.h b/F3:F303/MLX90640-allsky/strfunc.h
index 899d713..960eb73 100644
--- a/F3:F303/MLX90640-allsky/strfunc.h
+++ b/F3:F303/MLX90640-allsky/strfunc.h
@@ -23,11 +23,6 @@
 
 #include "usb_dev.h"
 
-#define printu(x)       do{USB_sendstr(u2str(x));}while(0)
-#define printi(x)       do{USB_sendstr(i2str(x));}while(0)
-#define printuhex(x)    do{USB_sendstr(uhex2str(x));}while(0)
-#define printfl(x,n)    do{USB_sendstr(float2str(x, n));}while(0)
-
 void u16s(uint16_t n, char *buf);
 void hexdump16(int (*sendfun)(const char *s), uint16_t *arr, uint16_t len);
 void hexdump(int (*sendfun)(const char *s), uint8_t *arr, uint16_t len);
diff --git a/F3:F303/MLX90640-allsky/usart.c b/F3:F303/MLX90640-allsky/usart.c
index 239539f..8e766e0 100644
--- a/F3:F303/MLX90640-allsky/usart.c
+++ b/F3:F303/MLX90640-allsky/usart.c
@@ -85,11 +85,12 @@ static int transmit_tbuf(){
 }
 
 // return 0 if can't write to ringbuffer
-int usart_putchar(const char ch){
-    int r = RB_write(&dmarb, (uint8_t*)&ch, 1);
+int usart_putbyte(uint8_t ch){
+    int r = RB_write(&dmarb, &ch, 1);
     if(r != 1){
-        if(transmit_tbuf()) r = RB_write(&dmarb, (uint8_t*)&ch, 1);
+        if(transmit_tbuf()) r = RB_write(&dmarb, &ch, 1);
     }
+    if(r < 0) r = 0;
     return r;
 }
 
@@ -163,7 +164,7 @@ void usart1_exti25_isr(){
     USART1->ICR = USART_ICR_CMCF; // clear character match flag
     register int l = UARTBUFSZI - DMA1_Channel5->CNDTR - 1; // substitute '\n' with '\0', omit empty strings!
     if(l > 0){
-        if(recvdata){ // user didn't read old data - mark as buffer overflow
+        if(recvdatalen){ // user didn't read old data - mark as buffer overflow
             bufovr = 1;
         }
         recvdata = rbuf[rbufno];
diff --git a/F3:F303/MLX90640-allsky/usart.h b/F3:F303/MLX90640-allsky/usart.h
index 1b1907d..b9f2dbc 100644
--- a/F3:F303/MLX90640-allsky/usart.h
+++ b/F3:F303/MLX90640-allsky/usart.h
@@ -32,6 +32,7 @@ int usart_ovr(); // RX overfull occured
 void usart_process(); // send next data portion
 int usart_setup(uint32_t speed); // set USART1 with given speed
 char *usart_getline(int *len); // read from rbin to buf
+int usart_send(const uint8_t *data, int len);
 int usart_sendstr(const char *str);
-int usart_putchar(const char ch);
+int usart_putbyte(uint8_t ch);
 void usart_stop();
diff --git a/F3:F303/MLX90640-allsky/usb_dev.h b/F3:F303/MLX90640-allsky/usb_dev.h
index b8a0808..a85227c 100644
--- a/F3:F303/MLX90640-allsky/usb_dev.h
+++ b/F3:F303/MLX90640-allsky/usb_dev.h
@@ -47,7 +47,7 @@ void linecoding_handler(usb_LineCoding *lc);
 #define RBINSZ      (128)
 
 #define newline()   USB_putbyte('\n')
-#define USND(s)     do{USB_sendstr(s); USB_putbyte('\n');}while(0)
+#define UN(s)     do{USB_sendstr(s); USB_putbyte('\n');}while(0)
 #define U(s)        USB_sendstr(s)
 
 int USB_sendall();
diff --git a/F3:F303/MLX90640-allsky/version.inc b/F3:F303/MLX90640-allsky/version.inc
index 7b1ccba..3b34625 100644
--- a/F3:F303/MLX90640-allsky/version.inc
+++ b/F3:F303/MLX90640-allsky/version.inc
@@ -1,2 +1,2 @@
-#define BUILD_NUMBER "1"
-#define BUILD_DATE "2025-09-28"
+#define BUILD_NUMBER "15"
+#define BUILD_DATE "2025-09-29"