From f10da7082b580f74a354095452a3c28a88c13e78 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?King=20K=C3=A9vin?= <kingkevin@cuvoodoo.info>
Date: Thu, 11 Mar 2021 13:53:00 +0100
Subject: [PATCH] application: add pull detection to type

---
 application.c | 60 +++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 51 insertions(+), 9 deletions(-)

diff --git a/application.c b/application.c
index 2c2239a..ec77516 100644
--- a/application.c
+++ b/application.c
@@ -238,9 +238,9 @@ static void command_types(void* argument)
 {
 	(void)argument; // we won't use the argument
 	float* voltages;
-	print_voltage_target(); // print target voltage (also sets measurement conditions)
-	puts("signal voltage pulled pulled\n");
-	puts(" pin     raw    down    up  \n");
+	print_target(); // print target voltage (also sets measurement conditions)
+	puts("signal voltage  pulled  pull-up pulled pull-down signal\n");
+	puts(" name  raw (V) down (V) (kOhm)  up (V)  (kOhm)    type \n");
 
 	// just to be sure, reset measurement conditions
 	gpio_set(GPIO_PORT(SIGNAL_PD_PIN), GPIO_PIN(SIGNAL_PD_PIN)); // ensure pull-down is not active
@@ -252,17 +252,59 @@ static void command_types(void* argument)
 		puts("     ");
 		mux_select(i); // select the channel
 		voltages = measure_voltages(); // measure raw voltages
-		print_voltage(voltages[2], 2);
+		print_fpu(voltages[2], 2);
+		const float raw = voltages[2]; // remember un-pulled voltage
 		puts("    ");
-		gpio_clear(GPIO_PORT(SIGNAL_PD_PIN), GPIO_PIN(SIGNAL_PD_PIN)); // pull-down signal
+
+		gpio_clear(GPIO_PORT(SIGNAL_PD_PIN), GPIO_PIN(SIGNAL_PD_PIN)); // pull down signal
 		voltages = measure_voltages(); // measure pulled down voltages
-		print_voltage(voltages[2], 2);
 		gpio_set(GPIO_PORT(SIGNAL_PD_PIN), GPIO_PIN(SIGNAL_PD_PIN)); // remove pull-down
-		puts("   ");
-		gpio_clear(GPIO_PORT(SIGNAL_PU_PIN), GPIO_PIN(SIGNAL_PU_PIN)); // pull-up signal
+		voltages[2] *= 2.0; // pulling creates a voltage divider (to ground)
+		const bool low = (voltages[2] < 0.5); // remember if we were able to pull it down
+		const float pullup = (2000.0 * (raw - voltages[2]) / voltages[2]) / 1000.0; // estimate external pull-up
+		print_fpu(voltages[2], 2);
+		puts("     ");
+		if (pullup > 100.0) {
+			puts(">100");
+		} else if (pullup < 1.0) {
+			puts(" <1 ");
+		} else {
+			printf(" %02u ", (uint32_t)round(pullup));
+		}
+		puts("    ");
+
+		gpio_clear(GPIO_PORT(SIGNAL_PU_PIN), GPIO_PIN(SIGNAL_PU_PIN)); // pull up signal
 		voltages = measure_voltages(); // measure pulled up voltages
-		print_voltage(voltages[2], 2);
 		gpio_set(GPIO_PORT(SIGNAL_PU_PIN), GPIO_PIN(SIGNAL_PU_PIN)); // remove pull-up
+		voltages[2] = voltages[2] *  2.0 - voltages[1]; // pulling creates a voltage divider (to target)
+		const bool high = (voltages[2] > 3.2 || voltages[2] > voltages[1] * 0.5); // remember if we were able to pull it up
+		const float pulldown = (2000.0 * voltages[2] / (voltages[1] - voltages[2])) / 1000.0; // estimate external pull-down
+		print_fpu(voltages[2], 2);
+		puts("    ");
+		if (pulldown > 100.0) {
+			puts(">100");
+		} else if (pulldown < 1.0) {
+			puts(" <1 ");
+		} else {
+			printf(" %02u ", (uint32_t)round(pulldown));
+		}
+		puts("    ");
+
+		if (low && high) {
+			if (pullup > 1.0 && pullup < 100.0 && (pulldown < 1.0 || pulldown > 100.0)) {
+				puts("pulled-up");
+			} else if (pulldown > 1.0 && pulldown < 100.0 && (pullup < 1.0 || pullup > 100.0)) {
+				puts("pulled-down");
+			} else {
+				puts("floating");
+			}
+		} else if (low) {
+			puts("low");
+		} else if (high) {
+			puts("high");
+		} else {
+			puts("unknown");
+		}
 		putc('\n');
 	}
 	mux_select(-1); // disable multiplexer