Got the DMA to work! (That was surprisingly easy).

3 files changed, 64 insertions, 9 deletions

diff --git a/include/spi.h b/include/spi.h
index 65e3a9d..a3ed89b 100644
--- a/include/spi.h
+++ b/include/spi.h
@@ -1,5 +1,11 @@
 #pragma once
 
+#include <stdlib.h>
+
 void enable_spi(void);
 
 void run_spi(void);
+
+void dma_transfer(void* output_buffer, size_t len);
+
+void wait_for_dma();
diff --git a/src/main.c b/src/main.c
index 8bf8e15..5f883f9 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,6 +1,7 @@
 #include <stdint.h>
 #include <stdio.h>
 
+#include "string.h"
 #include "ch573/gpio.h"
 #include "ch573/pwr.h"
 #include "ch573/uart.h"
@@ -127,9 +128,24 @@ int main(void)
 {
   printf("Running SPI.\n");
 
+  set_system_clock_60Mhz();
+
   enable_spi();
 
-  run_spi();
+  char buf[1024];
+  memset(buf, 0xf0, sizeof(buf));
+  for (int i = 0; i < 50; ++ i) {
+    buf[i] = 0xaa;
+    buf[sizeof(buf) - i] = 0xaa;
+  }
+
+  while (1) {
+    printf("Xfer.\n");
+    dma_transfer(buf, sizeof(buf));
+    wait_for_dma();
+  }
+
+  // run_spi();
 
   // GPIO_PORT.dir.set(GPIO_PORT_A, DIR_OUT, 8);
   // GPIO_PORT.pd_drv.set(GPIO_PORT_A, 0, 8);
diff --git a/src/spi.c b/src/spi.c
index 3105f1b..6d9fb2a 100644
--- a/src/spi.c
+++ b/src/spi.c
@@ -5,6 +5,8 @@
 #include "ch573/gpio.h"
 #include "ch573/spi.h"
 
+#define MAX_SPI_FIFO 8
+
 #define SPI CH573_SPI__SPI_T_INTF
 #define SPI0 ch573_spi__spi0
 
@@ -37,7 +39,7 @@ void enable_spi(void)
   GPIO_PORT.dir.set(GPIO_PORT_A, DIR_IN, 13);
   GPIO_PORT.dir.set(GPIO_PORT_A, DIR_IN, 15);
 
-  SPI.clock_div.set(SPI0, 16);
+  SPI.clock_div.set(SPI0, 25);
   SPI.ctrl_mod.all_clear.set(SPI0, 1);
   // SPI.ctrl_mod.set(SPI0, 0xe0);  // Set mosi and sck
 
@@ -47,16 +49,47 @@ void enable_spi(void)
   SPI.ctrl_cfg.dma_enable.set(SPI0, OFF);
 }
 
+// void write_color(uint8_t r, uint8_t g, uint8_t b)
+// {
+//
+//
+//   while (!SPI.int_flag.if_fifo_hf.get(SPI0));
+//   SPI.fifo.set(SPI0, r);
+//   SPI.fifo.set(SPI0, g);
+//   SPI.fifo.set(SPI0, b);
+// }
+
+void dma_transfer(void* output_buffer, size_t len)
+{
+  // Clear everything.
+  SPI.ctrl_mod.all_clear.set(SPI0, 1);
+  SPI.ctrl_mod.all_clear.set(SPI0, 0);
+
+  SPI.ctrl_mod.fifo_dir.set(SPI0, FIFO_DIR_OUTPUT);
+  SPI.dma_beg.set(SPI0, (uint32_t)output_buffer);
+  SPI.dma_end.set(SPI0, (uint32_t)(output_buffer + len));
+
+  SPI.total_count.set(SPI0, len);
+
+  // Start DMA.
+  SPI.ctrl_cfg.dma_enable.set(SPI0, ON);
+}
+
+void wait_for_dma()
+{
+  while (SPI.total_count.get(SPI0) > 0);
+}
+
 void run_spi(void)
 {
   GPIO_PORT.out.set(GPIO_PORT_A, ON, 12);
   while (1) {
-    GPIO_PORT_A->clr |= 1 << 12;
-    SPI.ctrl_mod.fifo_dir.set(SPI0, FIFO_DIR_OUTPUT);
-    // R8_SPI0_CTRL_MOD &= ~RB_SPI_FIFO_DIR;
-    SPI.data_buf.set(SPI0, 0xaa);
-    // R8_SPI0_BUFFER = 0xaa;
-    while (!SPI.int_flag.free.get(SPI0));
-    GPIO_PORT.out.set(GPIO_PORT_A, ON, 12);
+    SPI.total_count.set(SPI0, 1024);
+    // GPIO_PORT_A->clr |= 1 << 12;
+
+    while (SPI.fifo_count.get(SPI0) == 8);
+
+    SPI.fifo.set(SPI0, 0xaa);
+    SPI.total_count.set(SPI0, 1024);
   }
 }