Board bringup: talk to the chip and read IDs.

- atusd/ERRATA: mention that the reset circuit can go, as expected
- atusd/tools/Makefile: add include path to at86rf230.h
- atusd/tools/lib/atusd.c: include atusd.h, for consistency checking
- atusd/tools/lib/atusd.c (spi_begin, spi_end, spi_data_in, spi_data_out,
  spi_send_partial, spi_recv, spi_finish, spi_send): low-level functions
  to access our modified SPI
- atusd/tools/lib/atusd.h, atusd/tools/lib/atusd.c (atusd_reg_write,
  atusd_reg_read): register read and write access
- atusd/tools/try.c: read and print chip IDs

atusd/ERRATA

@@ -6,3 +6,7 @@
 
 - the footprint of the transistor (Q1) is reversed :-( It works after
   converting the chip from SOT to PLCC.
+
+- not an erratum, but with experiments showing power-on reset to be
+  reliable, we can consider removing the hardware reset circuit. This will
+  also simplify the layout.

atusd/tools/Makefile

@@ -1,5 +1,5 @@
 CC=mipsel-openwrt-linux-gcc
-CFLAGS=-Wall
+CFLAGS=-Wall -I../../atrf/fw/include
 
 MAIN = try
 OBJS = $(MAIN).c lib/atusd.o

atusd/tools/lib/atusd.c

@@ -5,6 +5,9 @@
 #include <fcntl.h>
 #include <sys/mman.h>
 
+#include "at86rf230.h"
+#include "atusd.h"
+
 
 enum {
 	VDD_OFF	= 1 << 6,	/* VDD disable, PD06 */
@@ -25,6 +28,7 @@ enum {
 #define GPIO(n)	REG(0x10000+(n))
 #define MSC(n)	REG(0x21000+(n))
 
+#define	PDPIN	GPIO(0x300)	/* port D pin level */
 #define PDDATS	GPIO(0x314)	/* port D data set */
 #define PDDATC	GPIO(0x318)	/* port D data clear */
 #define PDFUNS	GPIO(0x344)	/* port D function set */
@@ -142,6 +146,12 @@ void atusd_cycle(struct atusd_dsc *dsc)
 
 	/* start MMC clock output */
 	MSC_STRPCL = 2;
+
+	/*
+	 * Give power time to stabilize and the chip time to reset.
+	 * Experiments show that even usleep(0) is long enough.
+	 */
+	usleep(10*1000);
 }
 
 
@@ -161,3 +171,101 @@ void atusd_reset(struct atusd_dsc *dsc)
 	PDDATS = nSEL;
 	PDDATC = SLP_TR;
 }
+
+
+static void spi_begin(struct atusd_dsc *dsc)
+{
+	PDDATC = nSEL;
+}
+
+
+static void spi_end(struct atusd_dsc *dsc)
+{
+	PDDATS = nSEL;
+}
+
+
+static void spi_data_in(struct atusd_dsc *dsc)
+{
+	PDDIRC = MxSx;
+}
+
+
+static void spi_data_out(struct atusd_dsc *dsc)
+{
+	PDDIRS = MxSx;
+}
+
+
+
+/*
+ * Send a sequence of bytes but leave the clock high on the last bit, so that
+ * we can turn around the data line for reads.
+ */
+
+static void spi_send_partial(struct atusd_dsc *dsc, uint8_t v)
+{
+	uint8_t mask;
+
+	for (mask = 0x80; mask; mask >>= 1) {
+		PDDATC = SCLK;
+		if (v & mask)
+			PDDATS = MxSx;
+		else
+			PDDATC = MxSx;
+		PDDATS = SCLK;
+	}
+}
+
+
+static uint8_t spi_recv(struct atusd_dsc *dsc)
+{
+	uint8_t res = 0;
+        uint8_t mask;
+
+	for (mask = 0x80; mask; mask >>= 1) {
+		PDDATC = SCLK;
+		if (PDPIN & MxSx)
+			res |= mask;
+		PDDATS = SCLK;
+	}
+	PDDATC = SCLK;
+        return res;
+}
+
+
+static void spi_finish(struct atusd_dsc *dsc)
+{
+	PDDATC = SCLK;
+}
+
+
+static void spi_send(struct atusd_dsc *dsc, uint8_t v)
+{
+	spi_send_partial(dsc, v);
+	spi_finish(dsc);
+}
+
+
+void atusd_reg_write(struct atusd_dsc *dsc, uint8_t reg, uint8_t v)
+{
+	spi_begin(dsc);
+	spi_send(dsc, AT86RF230_REG_WRITE | reg);
+	spi_send(dsc, v);
+	spi_end(dsc);
+}
+
+
+uint8_t atusd_reg_read(struct atusd_dsc *dsc, uint8_t reg)
+{
+	uint8_t res;
+
+	spi_begin(dsc);
+	spi_send_partial(dsc, AT86RF230_REG_READ| reg);
+	spi_data_in(dsc);
+	res = spi_recv(dsc);
+	spi_finish(dsc);
+	spi_data_out(dsc);
+	spi_end(dsc);
+	return res;
+}

atusd/tools/lib/atusd.h

@@ -1,3 +1,9 @@
+#ifndef ATUSD_H
+#define	ATUSD_H
+
+#include <stdint.h>
+
+
 struct atusd_dsc;
 
 
@@ -5,3 +11,7 @@ struct atusd_dsc *atusd_open(void);
 void atusd_close(struct atusd_dsc *dsc);
 void atusd_cycle(struct atusd_dsc *dsc);
 void atusd_reset(struct atusd_dsc *dsc);
+void atusd_reg_write(struct atusd_dsc *dsc, uint8_t reg, uint8_t v);
+uint8_t atusd_reg_read(struct atusd_dsc *dsc, uint8_t reg);
+
+#endif /* ATUSD_H */

atusd/tools/try.c

@@ -1,19 +1,28 @@
+#include <stdint.h>
 #include <stdio.h>
 #include <unistd.h>
 
+#include "at86rf230.h"
 #include "lib/atusd.h"
 
 
 int main(void)
 {
 	struct atusd_dsc *dsc;
-	char tmp;
+	uint8_t part, version, man_id_0, man_id_1;
 
 	dsc = atusd_open();
-	read(1, &tmp, 1);
-fprintf(stderr, "cycling\n");
+
 	atusd_cycle(dsc);
-	read(1, &tmp, 1);
+//	atusd_reset(dsc);
+
+        part = atusd_reg_read(dsc, REG_PART_NUM);
+        version = atusd_reg_read(dsc, REG_VERSION_NUM);
+        man_id_0 = atusd_reg_read(dsc, REG_MAN_ID_0);
+        man_id_1 = atusd_reg_read(dsc, REG_MAN_ID_1);
+        printf("part 0x%02x version %u manufacturer xxxx%02x%02x\n",
+            part, version, man_id_1, man_id_0);
+
 	atusd_close(dsc);
 
 	return 0;