demo: introduce graycode generator mode

[libsigrok.git] / src / hardware / demo / protocol.c

diff --git a/src/hardware/demo/protocol.c b/src/hardware/demo/protocol.c
index 53ae247726ab9af2382a084af10977b029f17c7a..05f3f9d33fd3f62715d83e674b3f6f829d1d0de0 100644 (file)
--- a/src/hardware/demo/protocol.c
+++ b/src/hardware/demo/protocol.c
@@ -245,6 +245,19 @@ SR_PRIV void demo_generate_analog_pattern(struct analog_gen *ag, uint64_t sample
        }
 }
 
+static uint64_t encode_number_to_gray(uint64_t nr)
+{
+       return nr ^ (nr >> 1);
+}
+
+static void set_logic_data(uint64_t bits, uint8_t *data, size_t len)
+{
+       while (len--) {
+               *data++ = bits & 0xff;
+               bits >>= 8;
+       }
+}
+
 static void logic_generator(struct sr_dev_inst *sdi, uint64_t size)
 {
        struct dev_context *devc;
@@ -253,6 +266,7 @@ static void logic_generator(struct sr_dev_inst *sdi, uint64_t size)
        uint8_t *sample;
        const uint8_t *image_col;
        size_t col_count, col_height;
+       uint64_t gray;
 
        devc = sdi->priv;
 
@@ -326,6 +340,15 @@ static void logic_generator(struct sr_dev_inst *sdi, uint64_t size)
                        devc->step %= col_count;
                }
                break;
+       case PATTERN_GRAYCODE:
+               for (i = 0; i < size; i += devc->logic_unitsize) {
+                       devc->step++;
+                       devc->step &= devc->all_logic_channels_mask;
+                       gray = encode_number_to_gray(devc->step);
+                       gray &= devc->all_logic_channels_mask;
+                       set_logic_data(gray, &devc->logic_data[i], devc->logic_unitsize);
+               }
+               break;
        default:
                sr_err("Unknown pattern: %d.", devc->logic_pattern);
                break;