Added some MPSSE command definitions to decrease magic number usage.

iceprog/iceprog.c

@@ -42,6 +42,80 @@ static bool verbose = false;
 static bool ftdic_latency_set = false;
 static unsigned char ftdi_latency;
 
+/* MPSSE engine command definitions */
+enum mpsse_cmd
+{
+	/* Mode commands */
+	MC_SETB_LOW = 0x80, /* Set Data bits LowByte */
+	MC_READB_LOW = 0x81, /* Read Data bits LowByte */
+	MC_SETB_HIGH = 0x82, /* Set Data bits HighByte */
+	MC_READB_HIGH = 0x83, /* Read data bits HighByte */
+	MC_LOOPBACK_EN = 0x84, /* Enable loopback */
+	MC_LOOPBACK_DIS = 0x85, /* Disable loopback */
+	MC_SET_CLK_DIV = 0x86, /* Set clock divisor */
+	MC_FLUSH = 0x87, /* Flush buffer fifos to the PC. */
+	MC_WAIT_H = 0x88, /* Wait on GPIOL1 to go high. */
+	MC_WAIT_L = 0x89, /* Wait on GPIOL1 to go low. */
+	MC_TCK_X5 = 0x8A, /* Disable /5 div, enables 60MHz master clock */
+	MC_TCK_D5 = 0x8B, /* Enable /5 div, backward compat to FT2232D */
+	MC_EN_3PH_CLK = 0x8C, /* Enable 3 phase clk, DDR I2C */
+	MC_DIS_3PH_CLK = 0x8D, /* Disable 3 phase clk */
+	MC_CLK_N = 0x8E, /* Clock every bit, used for JTAG */
+	MC_CLK_N8 = 0x8F, /* Clock every byte, used for JTAG */
+	MC_CLK_TO_H = 0x94, /* Clock until GPIOL1 goes high */
+	MC_CLK_TO_L = 0x95, /* Clock until GPIOL1 goes low */
+	MC_EN_ADPT_CLK = 0x96, /* Enable adaptive clocking */
+	MC_DIS_ADPT_CLK = 0x97, /* Disable adaptive clocking */
+	MC_CLK8_TO_H = 0x9C, /* Clock until GPIOL1 goes high, count bytes */
+	MC_CLK8_TO_L = 0x9D, /* Clock until GPIOL1 goes low, count bytes */
+	MC_TRI = 0x9E, /* Set IO to only drive on 0 and tristate on 1 */
+	/* CPU mode commands */
+	MC_CPU_RS = 0x90, /* CPUMode read short address */
+	MC_CPU_RE = 0x91, /* CPUMode read extended address */
+	MC_CPU_WS = 0x92, /* CPUMode write short address */
+	MC_CPU_WE = 0x93, /* CPUMode write extended address */
+};
+
+/* Transfer Command bits */
+
+/* All byte based commands consist of:
+ * - Command byte
+ * - Length lsb
+ * - Length msb
+ *
+ * If data out is enabled the data follows after the above command bytes,
+ * otherwise no additional data is needed.
+ * - Data * n
+ *
+ * All bit based commands consist of:
+ * - Command byte
+ * - Length
+ *
+ * If data out is enabled a byte containing bitst to transfer follows.
+ * Otherwise no additional data is needed. Only up to 8 bits can be transferred
+ * per transaction when in bit mode.
+ */
+
+/* b 0000 0000
+ *   |||| |||`- Data out negative enable. Update DO on negative clock edge.
+ *   |||| ||`-- Bit count enable. When reset count represents bytes.
+ *   |||| |`--- Data in negative enable. Latch DI on negative clock edge.
+ *   |||| `---- LSB enable. When set clock data out LSB first.
+ *   ||||
+ *   |||`------ Data out enable
+ *   ||`------- Data in enable
+ *   |`-------- TMS mode enable
+ *   `--------- Special command mode enable. See mpsse_cmd enum.
+ */
+
+#define MC_DATA_TMS  (0x40) /* When set use TMS mode */
+#define MC_DATA_IN   (0x20) /* When set read data (Data IN) */
+#define MC_DATA_OUT  (0x10) /* When set write data (Data OUT) */
+#define MC_DATA_LSB  (0x08) /* When set input/output data LSB first. */
+#define MC_DATA_ICN  (0x04) /* When set receive data on negative clock edge */
+#define MC_DATA_BITS (0x02) /* When set count bits not bytes */
+#define MC_DATA_OCN  (0x01) /* When set update data on negative clock edge */
+
 static void check_rx()
 {
 	while (1) {
@@ -96,7 +170,8 @@ static void send_spi(uint8_t *data, int n)
 	if (n < 1)
 		return;
 
-	send_byte(0x11);
+	/* Output only, update data on negative clock edge. */
+	send_byte(MC_DATA_OUT | MC_DATA_OCN);
 	send_byte(n - 1);
 	send_byte((n - 1) >> 8);
 
@@ -112,7 +187,8 @@ static void xfer_spi(uint8_t *data, int n)
 	if (n < 1)
 		return;
 
-	send_byte(0x31);
+	/* Input and output, update data on negative edge read on positive. */
+	send_byte(MC_DATA_IN | MC_DATA_OUT | MC_DATA_OCN);
 	send_byte(n - 1);
 	send_byte((n - 1) >> 8);
 
@@ -140,15 +216,15 @@ static void set_gpio(int slavesel_b, int creset_b)
 		gpio |= 0x80;
 	}
 
-	send_byte(0x80);
-	send_byte(gpio);
-	send_byte(0x93);
+	send_byte(MC_SETB_LOW);
+	send_byte(gpio); /* Value */
+	send_byte(0x93); /* Direction */
 }
 
 static int get_cdone()
 {
 	uint8_t data;
-	send_byte(0x81);
+	send_byte(MC_READB_LOW);
 	data = recv_byte();
 	// ADBUS6 (GPIOL2)
 	return (data & 0x40) != 0;
@@ -641,16 +717,17 @@ int main(int argc, char **argv)
 
 	ftdic_latency_set = true;
 
+	/* Enter MPSSE (Multi-Protocol Synchronous Serial Engine) mode. Set all pins to output. */
 	if (ftdi_set_bitmode(&ftdic, 0xff, BITMODE_MPSSE) < 0) {
 		fprintf(stderr, "Failed to set BITMODE_MPSSE on iCE FTDI USB device.\n");
 		error(2);
 	}
 
 	// enable clock divide by 5
-	send_byte(0x8b);
+	send_byte(MC_TCK_D5);
 
 	// set 6 MHz clock
-	send_byte(0x86);
+	send_byte(MC_SET_CLK_DIV);
 	send_byte(0x00);
 	send_byte(0x00);
 
@@ -712,13 +789,13 @@ int main(int argc, char **argv)
 			send_spi(buffer, rc);
 		}
 
-		// add 48 dummy bits
-		send_byte(0x8f);
+		// add 48 dummy bits (aka 6 bytes)
+		send_byte(MC_CLK_N8);
 		send_byte(0x05);
 		send_byte(0x00);
 
 		// add 1 more dummy bit
-		send_byte(0x8e);
+		send_byte(MC_CLK_N);
 		send_byte(0x00);
 
 		fprintf(stderr, "cdone: %s\n", get_cdone() ? "high" : "low");