1 files changed, 55 insertions, 0 deletions
diff --git a/firmware/usrp2/lib/spi.c b/firmware/usrp2/lib/spi.c
new file mode 100644
index 000000000..6f2f74899
--- /dev/null
+++ b/firmware/usrp2/lib/spi.c
@@ -0,0 +1,55 @@
+/*
+ * Copyright 2012 Ettus Research LLC
+ * Copyright 2007,2008 Free Software Foundation, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "spi.h"
+#include "memory_map.h"
+#include "nonstdio.h"
+
+void spi_init(void)
+{
+    spi_core->divider = 10;
+}
+
+void spi_wait(void)
+{
+    while ((readback_mux->irqs & SPI_READY_IRQ) == 0){
+        //NOP
+    }
+}
+
+uint32_t spi_transact(bool readback, int slave, uint32_t data, int length, uint32_t flags)
+{
+    uint32_t control_word = 0;
+    control_word |= (slave << SPI_CORE_SLAVE_SELECT_SHIFT);
+    control_word |= (length << SPI_CORE_NUM_BITS_SHIFT);
+    if ((flags & SPI_PUSH_RISE)  != 0) control_word |= (1 << SPI_CORE_DATA_OUT_EDGE_SHIFT);
+    if ((flags & SPI_PUSH_FALL)  != 0) control_word |= (0 << SPI_CORE_DATA_OUT_EDGE_SHIFT);
+    if ((flags & SPI_LATCH_RISE) != 0) control_word |= (1 << SPI_CORE_DATA_IN_EDGE_SHIFT);
+    if ((flags & SPI_LATCH_FALL) != 0) control_word |= (0 << SPI_CORE_DATA_IN_EDGE_SHIFT);
+
+    const uint32_t data_out = data << (32 - length);
+
+    spi_wait();
+    spi_core->control = control_word;
+    spi_core->data = data_out;
+
+    if (!readback) return 0;
+
+    spi_wait();
+    return readback_mux->spi;
+}