asix-sigma: rephrase some of the FPGA command exchange

[libsigrok.git] / src / hardware / asix-sigma / protocol.h

diff --git a/src/hardware/asix-sigma/protocol.h b/src/hardware/asix-sigma/protocol.h
index a32ee15e724f40b799246e28967beb4a6e2fc86e..edace1e54970492978d348b50e280730a745c1d4 100644 (file)
--- a/src/hardware/asix-sigma/protocol.h
+++ b/src/hardware/asix-sigma/protocol.h
@@ -85,22 +85,34 @@ enum sigma_read_register {
        READ_TEST               = 15,
 };
 
+/*
+ * FPGA commands are 8bits wide. The upper nibble is a command opcode,
+ * the lower nibble can carry operand values. 8bit register addresses
+ * and 8bit data values get communicated in two steps.
+ */
+
+/* Register access. */
 #define REG_ADDR_LOW           (0x0 << 4)
 #define REG_ADDR_HIGH          (0x1 << 4)
 #define REG_DATA_LOW           (0x2 << 4)
 #define REG_DATA_HIGH_WRITE    (0x3 << 4)
 #define REG_READ_ADDR          (0x4 << 4)
-#define REG_DRAM_WAIT_ACK      (0x5 << 4)
-
-/* Bit (1 << 4) can be low or high (double buffer / cache) */
-#define REG_DRAM_BLOCK         (0x6 << 4)
-#define REG_DRAM_BLOCK_BEGIN   (0x8 << 4)
-#define REG_DRAM_BLOCK_DATA    (0xa << 4)
+#define REG_ADDR_ADJUST                (1 << 0) /* Auto adjust register address. */
+#define REG_ADDR_DOWN          (1 << 1) /* 1 decrement, 0 increment. */
+#define REG_ADDR_INC           (REG_ADDR_ADJUST)
+#define REG_ADDR_DEC           (REG_ADDR_ADJUST | REG_ADDR_DOWN)
+
+/* Sample memory access. */
+#define REG_DRAM_WAIT_ACK      (0x5 << 4) /* Wait for completion. */
+#define REG_DRAM_BLOCK         (0x6 << 4) /* DRAM to BRAM, plus bank select. */
+#define REG_DRAM_BLOCK_BEGIN   (0x8 << 4) /* Read first BRAM bytes. */
+#define REG_DRAM_BLOCK_DATA    (0xa << 4) /* Read full BRAM block. */
+#define REG_DRAM_SEL_N         (0x1 << 4) /* Bank select, added to 6/8/a. */
+#define REG_DRAM_SEL_BOOL(b)   ((b) ? REG_DRAM_SEL_N : 0)
 
 #define LEDSEL0                        6
 #define LEDSEL1                        7
 
-#define NEXT_REG               1
 
 #define EVENTS_PER_CLUSTER     7