From 7661170957df45c954fbdbc8d24cb9542986cf27 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?King=20K=C3=A9vin?= <kingkevin@cuvoodoo.info>
Date: Tue, 26 Jan 2016 10:16:14 +0100
Subject: [PATCH] vfd has how two lines

---
 main.c | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/main.c b/main.c
index 06e0e42..5bbebb2 100644
--- a/main.c
+++ b/main.c
@@ -123,6 +123,7 @@ int main(void)
 	uint8_t vfd_place = 0; // the place on which the next character will be displayed on the VFD
 	bool vfd_flag = false; // do something with the VFD
 	char c = 0; // the character to display
+	char previous_line[VFD_DIGITS] = {0};
 	while (true) {
 		while (usart_received) { // echo every received character
 			c = usart_getchar();
@@ -136,13 +137,26 @@ int main(void)
 			vfd_flag = false;
 			printf("%c", c); // transmit receive character
 			gpio_toggle(LED_PORT, LED_PIN); // toggle LED to show activity
-			if (c=='\r' || c=='\n') { // on newline
-				vfd_clear(); // clear display
-				vfd_place = 0; // restart from beginning
+			if (c=='\r' || c=='\n') { // on (new) newline
+				if (vfd_place>0) { // only on new newline
+					vfd_clear(); // clear display
+					vfd_place = 0; // restart from beginning
+					// show previous line on digits (and clear it
+					for (uint8_t i=0; i<LENGTH(previous_line) && i<VFD_DIGITS; i++) {
+						vfd_digit(i,previous_line[i]);
+						previous_line[i] = 0;
+					}
+				}
 			} else {
-				vfd_digit(vfd_place,c); // display character on digit
-				vfd_matrix(vfd_place,c); // display character on matrix
-				vfd_place++; // go to next place
+				// show typed character for current line on matrix
+				if (vfd_place < VFD_MATRIX) {
+					vfd_matrix(vfd_place,c); // display character on digit
+				}
+				// save character for the net previous line
+				if (vfd_place < LENGTH(previous_line)) {
+					previous_line[vfd_place] = c;
+				}
+				vfd_place++; // go to next place (you can overflow it and confuse the newline)
 			}
 		}	
 		__WFI(); // go to sleep