Debug config for vs code ide

.vscode/launch.json

@@ -0,0 +1,27 @@
+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "(gdb) Launch",
+            "type": "cppdbg",
+            "request": "launch",
+            "program": "${workspaceFolder}/bin/test",
+            "args": [],
+            "stopAtEntry": false,
+            "cwd": "${workspaceFolder}",
+            "environment": [],
+            "externalConsole": false,
+            "MIMode": "gdb",
+            "setupCommands": [
+                {
+                    "description": "Enable pretty-printing for gdb",
+                    "text": "-enable-pretty-printing",
+                    "ignoreFailures": true
+                }
+            ]
+        }
+    ]
+}

src/gpio.c

@@ -41,6 +41,24 @@ static int ftdi_open(void)
     return EXIT_SUCCESS;
 }
 
+static int gpio_read_mask(const struct gpio *gpio, unsigned char *mask)
+{
+    int res;
+
+    if(NULL == gpio || NULL == mask) {
+        return EXIT_FAILURE;
+    }
+
+    res = ftdi_read_data(ftdi_obj.ftdi, mask, 1);
+    if(res < 0) {
+        syslog(LOG_ERR, "unable to readfrom ftdi device: %d (%s)\n", res,
+               ftdi_get_error_string(ftdi_obj.ftdi));
+        return EXIT_FAILURE;
+    }
+
+    return EXIT_SUCCESS;
+}
+
 int gpio_open(const struct gpio *gpio)
 {
     int res;
@@ -62,6 +80,7 @@ int gpio_open(const struct gpio *gpio)
     }
 
     ftdi_obj.bit_mask |= (unsigned char)gpio->pin;
+    syslog(LOG_DEBUG, "bitmask: 0x%02x\n", ftdi_obj.bit_mask);
     res = ftdi_set_bitmode(ftdi_obj.ftdi, ftdi_obj.bit_mask, BITMODE_BITBANG);
     if(res < 0) {
         syslog(LOG_ERR, "unable to set bit bang mode: %d (%s)\n", res,
@@ -103,8 +122,8 @@ int gpio_read(const struct gpio *gpio, unsigned int *value)
         return EXIT_FAILURE;
     }
 
-    res = ftdi_read_data(ftdi_obj.ftdi, &buf, 1);
-    if(res < 0) {
+    res = gpio_read_mask(gpio, &buf);
+    if(res != EXIT_SUCCESS) {
         syslog(LOG_ERR, "unable to readfrom ftdi device: %d (%s)\n", res,
                ftdi_get_error_string(ftdi_obj.ftdi));
         return EXIT_FAILURE;
@@ -122,27 +141,27 @@ int gpio_read(const struct gpio *gpio, unsigned int *value)
 int gpio_write(const struct gpio *gpio, unsigned int value)
 {
     int res;
-    unsigned int current_state;
     unsigned char buf;
 
     if(NULL == gpio) {
         return EXIT_FAILURE;
     }
 
-    res = gpio_read(gpio, &current_state);
+    res = gpio_read_mask(gpio, &buf);
     if(res != EXIT_SUCCESS) {
-        syslog(LOG_ERR, "write failed for 0x%x, error %d (%s)\n", value, res,
+        syslog(LOG_ERR, "write failed for 0x%02x, error %d (%s)\n", buf, res,
                ftdi_get_error_string(ftdi_obj.ftdi));
         return EXIT_FAILURE;
     }
 
-    buf = (unsigned char)current_state;
+    syslog(LOG_DEBUG, "current state: 0x%02x\n", buf);
     if(value == 0) {
         buf &= ~(unsigned char)(gpio->pin);
     }
     else {
         buf |= (unsigned char)(gpio->pin);
     }
+    syslog(LOG_DEBUG, "new state: 0x%02x\n", buf);
 
     res = ftdi_write_data(ftdi_obj.ftdi, &buf, 1);
     if(res < 0) {

src/main.c

@@ -5,39 +5,66 @@
 
 #include <gpio.h>
 
-static const struct gpio gpio = {
-    .pin = 0x08,
+/*
+#define GPIO1 0x08  // TX  (brown)
+#define GPIO2 0x01  // TX  (orange)
+#define GPIO3 0x02  // RX  (yellow)
+#define GPIO4 0x14  // RTS (green on FTDI) + DTR (on SparkFun breakout)
+*/
+
+static const struct gpio gpio_1 = {
+    .pin = 0x08, /* CTS (brown wire on FTDI cable) */
+};
+static const struct gpio gpio_2 = {
+    .pin = 0x01, /* TX (orange wire on FTDI cable) */
 };
 
 int main(int argc, char *argv[])
 {
-    int res;
+    int res, cnt;
     unsigned int value;
 
     openlog("ftdi_gpio", LOG_CONS | LOG_PID | LOG_NDELAY, LOG_LOCAL1);
 
-    res = gpio_open(&gpio);
+    res = gpio_open(&gpio_1);
+    res |= gpio_open(&gpio_2);
     if(res != EXIT_SUCCESS) {
-        syslog(LOG_ERR, "Unable to open gpio pin %u\n", gpio.pin);
+        syslog(LOG_ERR, "Unable to open gpio\n");
         return res;
     }
 
-    res = gpio_write(&gpio, 0x00);
+    for(cnt = 0; cnt < 10; cnt++) {
+        value = cnt & 0x01;
+        res = gpio_write(&gpio_1, value);
+        if(cnt % 2) {
+            res |= gpio_write(&gpio_2, value);
+        }
         if(res != EXIT_SUCCESS) {
-        syslog(LOG_ERR, "Unable to write to gpio pin %u\n", gpio.pin);
-        gpio_close(&gpio);
+            syslog(LOG_ERR, "Unable to write to gpio\n");
+            gpio_close(&gpio_1);
+            gpio_close(&gpio_2);
             return res;
         }
 
-    res = gpio_read(&gpio, &value);
+        res = gpio_read(&gpio_1, &value);
         if(res != EXIT_SUCCESS) {
-        syslog(LOG_ERR, "Unable to read from gpio pin %u\n", gpio.pin);
-        gpio_close(&gpio);
+            syslog(LOG_ERR, "Unable to read from gpio pin %u\n", gpio_1.pin);
+            gpio_close(&gpio_1);
             return res;
         }
-    printf("read value: 0x%02x\n", value);
-
-    gpio_close(&gpio);
+        printf("read 1 value: 0x%02x\n", value);
+        if(cnt % 2) {
+            res = gpio_read(&gpio_2, &value);
+            if(res != EXIT_SUCCESS) {
+                syslog(LOG_ERR, "Unable to read from gpio pin %u\n", gpio_2.pin);
+                gpio_close(&gpio_2);
+                return res;
+            }
+            printf("read 2 value: 0x%02x\n", value);
+        }
+        sleep(1);
+    }
+    gpio_close(&gpio_1);
 
     return EXIT_SUCCESS;
 }