2 files changed, 11 insertions, 15 deletions
diff --git a/firmware/zpu/lib/memory_map.h b/firmware/zpu/lib/memory_map.h
index 8568872d0..4290ee20a 100644
--- a/firmware/zpu/lib/memory_map.h
+++ b/firmware/zpu/lib/memory_map.h
@@ -122,6 +122,8 @@ typedef struct {
   volatile uint32_t irqs;
 } router_status_t;
 
+#define SPI_READY_IRQ (1 << 12)
+
 #define router_status ((router_status_t *) READBACK_BASE)
 #define readback_mux ((router_status_t *) READBACK_BASE) //alias with a better name
 
diff --git a/firmware/zpu/lib/spi.c b/firmware/zpu/lib/spi.c
index de3645fe3..190658d61 100644
--- a/firmware/zpu/lib/spi.c
+++ b/firmware/zpu/lib/spi.c
@@ -19,17 +19,17 @@
 #include "spi.h"
 #include "memory_map.h"
 #include "nonstdio.h"
-#include "mdelay.h"
 
 void spi_init(void)
 {
-  spi_core->divider = 100;
+    spi_core->divider = 10;
 }
 
 void spi_wait(void)
 {
-  //assumption that divider is reasonably small
-  mdelay(1);
+    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)
@@ -37,20 +37,14 @@ uint32_t spi_transact(bool readback, int slave, uint32_t data, int length, uint3
     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_IN_EDGE_SHIFT);
-    if ((flags & SPI_PUSH_FALL)  != 0) control_word |= (0 << SPI_CORE_DATA_IN_EDGE_SHIFT);
-    if ((flags & SPI_LATCH_RISE) != 0) control_word |= (1 << SPI_CORE_DATA_OUT_EDGE_SHIFT);
-    if ((flags & SPI_LATCH_FALL) != 0) control_word |= (0 << SPI_CORE_DATA_OUT_EDGE_SHIFT);
-
-    uint32_t data_out_rev = 0;
-    for (size_t i = 0; i < length; i++){
-        const int bit = ((data >> i) & 0x1);
-        data_out_rev |= (bit << (length - i - 1));
-    }
+    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);
 
     spi_wait();
     spi_core->control = control_word;
-    spi_core->data = data_out_rev;
+    spi_core->data = (data << (32 - length));
 
     if (readback) spi_wait();