diff --git a/src/.gitignore b/src/.gitignore
index 2f8c9ea..2921dc0 100644
--- a/src/.gitignore
+++ b/src/.gitignore
@@ -1 +1,2 @@
 thhor.userrow
+*.s
diff --git a/src/Makefile b/src/Makefile
index 5d8d444..60c61e7 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -11,22 +11,13 @@ thhor_all: thhor.eeprom thhor.userrow
 CFLAGS_thhor = -Ibch4369 -DHAVE_FPGA -DSEND_HEX -DTHHOR
 MCU_thhor = attiny3224
 SN_thhor = 1
-C_FILES_thhor = config.c uart.c cmd.c base85.c rtc.c adc.c pwm.c spi.c flash.c bch4369.c pipe.c fpga.c
+# Link order defines ADC packet composition
+# main() is first, with .bss.magic
+# config.c includes .eeprom `port_config`, that should go second
+# .bss: rtc, adc, flash, uart, spi, pipe
+C_FILES_thhor = config.c rtc.c adc.c flash.c uart.c cmd.c base85.c pwm.c spi.c bch4369.c pipe.c fpga.c
 S_FILES_thhor = uart_tx.S base85a.S
 
-dose_all: dose.eeprom dose.userrow
-SN_dose = 1
-MCU_dose = $(MCU_$(VAR))
-MCU_nFETs = attiny424
-MCU_FPGA = attiny3224
-
-VAR=nFETs
-C_FILES_nFETs = 
-C_FILES_FPGA = fpga.c
-CFLAGS_dose  = -DHAVE_$(VAR)
-C_FILES_dose = config.c rtc.c adc.c pwm.c $(C_FILES_$(VAR)) uart.c cmd.c pipe.c base85.c bch4369.c spi.c flash.c
-S_FILES_dose = uart_tx.S base85a.S
-
 MCU = $(MCU_$(PROJ))
 OPT = -Os
 
@@ -82,23 +73,24 @@ pMCU-attiny824 = t824
 pMCU-attiny3224 = t3224
 
 # WDT
-fuse0_dose= 0x00
+fuse0_thhor= 0x00
 # BOD
-fuse1_dose= 0x00
+fuse1_thhor= 0x00
 # OSC, 20 MHz
-fuse2_dose= 0x7e
-# ???
-fuse4_dose= 0xff
+fuse2_thhor= 0x7e
+# Reserved
+fuse3_thhor= 0xff
+# Reserved
+fuse4_thhor= 0xff
 # SYS0 (default 0xf6)  RESET, EEPROM erase
-fuse5_dose= 0xf7
+fuse5_thhor= 0xf7
 # SYS1 startup time (64ms)
-fuse6_dose= 0xff 
+fuse6_thhor= 0xff
 # APPEND
-fuse7_dose= 0x00 
+fuse7_thhor= 0x00
 # BOOTEND
-fuse8_dose= 0x00
-fuses_dose =$(patsubst %, 0x%, 00 00 7e ff ff f7 ff 00  00)
-fuses_thhor = $(fuses_dose)
+fuse8_thhor= 0x00
+fuses_thhor =$(patsubst %, 0x%, 00 00 7e ff ff f7 ff 00 00)
 
 AVRDUDEPROG = avrdude
 AVRDUDE = $(AVRDUDEPROG)
@@ -107,8 +99,6 @@ AVRDUDE_PORT = /dev/ttyUSB0
 
 AD = $(AVRDUDE) -p $(pMCU-$(MCU)) -P $(AVRDUDE_PORT) -c $(AVRDUDE_PROGRAMMER)
 
-
-
 sig_dose = 0x1e 0x92 0x2c
 sig_thhor = 0x1e 0x95 0x28
 
diff --git a/src/cmd.c b/src/cmd.c
index dd3edc5..b687341 100644
--- a/src/cmd.c
+++ b/src/cmd.c
@@ -244,17 +244,38 @@ void parse_command(const uint8_t *s, uint8_t n)
 			goto send_buffer;
 		break;
 	case 'P':
+		if (cmd_flag('!'))
+			pipe.dest = 0;
 		if (have_b)
-			pipe_config((void*)cmd_buffer);
+			pipe_config((void*)cmd_buffer, (void*)bptr);
 		r = pipe_poll();
 		break;
 #ifdef HAVE_FPGA
 	case 'O':
 		r = fpga_power();
-		if (bflg == 1)
+		if (bflg & 1)
+			// "O1" power off
 			fpga_power_off();
-		else if (bflg == 2)
+		if (bflg >= 2) {
+			// "O2" power on
 			fpga_power_on();
+			if (!r) {
+				fpga_reset();
+				break;
+			}
+		}
+		if (bflg <= 2)
+			break;
+		if (bflg <= 8 && r==as_configured)
+			// "O2": configure if unconfigured
+			break;
+		if (bflg & 8) {
+			// "O3": power of if unconfigured
+			fpga_power_off();
+			break;
+		}
+		// "O4" configure unconditionally
+		fpga_config(config.fpga_config_page, config.fpga_config_count);
 		break;
 	case 'C':
 		if (cmd_flag('@')) {
diff --git a/src/config.h b/src/config.h
index 39d346d..3412198 100644
--- a/src/config.h
+++ b/src/config.h
@@ -23,6 +23,8 @@ struct config {
 	uint16_t  pwm_min;
 	uint16_t  pwm_max;
 #endif
+	uint16_t  fpga_config_page;
+	uint16_t  fpga_config_count;
 };
 
 enum magic_flags {
@@ -32,7 +34,7 @@ enum magic_flags {
 #endif
 #ifdef HAVE_FPGA
 	MAGIC       = 0xC5,
-	VERSION     = 0x01,
+	VERSION     = 0x00,
 #endif
 };
 
@@ -159,6 +161,8 @@ extern struct magic {
 #if 0
 #define _memcopy memcpy
 #define _memcopyyz memcpy
+#define _memcopyzy memcpy
+#define _memcmpyz memcmp
 #else
 // avoid the avr-libc memcpy.
 // ¡ n must not be zero !
@@ -192,6 +196,43 @@ void _memcopyyz(uint8_t *d, uint8_t *s, uint8_t n)
 		:: "r0", "memory");
 }
 
+static inline
+void _memcopyzy(uint8_t *d, uint8_t *s, uint8_t n)
+{
+	__asm__ volatile ("\n"
+		"1:"		"\n\t"
+		"ld r0, Y+"	"\n\t"
+		"st Z+, r0"	"\n\t"
+		"dec %[N]"	"\n\t"
+		"brne 1b"	"\n"
+		: [D] "+z" (d),
+		  [S] "+y" (s),
+		  [N] "+r" (n)
+		:: "r0", "memory");
+}
+
+static inline
+uint8_t _memcmpyz(uint8_t *d, uint8_t *s, uint8_t n)
+{
+	uint8_t r;
+	__asm__ volatile (
+		"\n"
+		"1:"		"\n\t"
+		"ld %[R], Y+"	"\n\t"
+		"ld r0, Z+"	"\n\t"
+		"sub %[R], r0"	"\n\t"
+		"breq 1f"	"\n\t"
+		"dec %[N]"	"\n\t"
+		"brne 1b"	"\n"
+		"1:"		"\n"
+		: [D] "+x" (d),
+		  [S] "+y" (s),
+		  [N] "+r" (n),
+		  [R] "=r" (r)
+		:
+		: "r0", "memory");
+	return r;
+}
 
 #endif
 
diff --git a/src/eeprom.ld b/src/eeprom.ld
index 0654d25..b72db90 100644
--- a/src/eeprom.ld
+++ b/src/eeprom.ld
@@ -4,14 +4,14 @@
 */
 MEMORY 
 {
-    eemap   : ORIGIN =   0x1400,  LENGTH = 0x100
-    eedef   : ORIGIN = 0x810000,  LENGTH = 0x100
-    uumap   : ORIGIN =   0x1300,  LENGTH = 0x20
-    uudef   : ORIGIN = 0x850000,  LENGTH = 0x20
+    eemap (rw!x) : ORIGIN = 0x801400, LENGTH = 0x100
+    eedef (rw!x) : ORIGIN = 0x810000, LENGTH = 0x100
+    uumap (rw!x) : ORIGIN = 0x801300, LENGTH = 0x020
+    uudef (rw!x) : ORIGIN = 0x850000, LENGTH = 0x020
 }
 SECTIONS
 {
-    .eemap 0x1400:
+    .eemap 0x801400:
     {
 	ee1_start = .;
 	*(.eeprom1)
@@ -22,7 +22,7 @@ SECTIONS
 	ee9_end = .;
 	ee9_size = ee9_end - ee9_start;
     } >eemap AT >eedef
-    .uumap 0x1300:
+    .uumap 0x801300:
     {
         *(.userrow)
     } >uumap AT >uudef
diff --git a/src/flash.h b/src/flash.h
index c509eee..46af975 100644
--- a/src/flash.h
+++ b/src/flash.h
@@ -28,6 +28,7 @@ uint8_t flash_cmd(uint16_t mode, uint16_t what, uint16_t page, uint16_t byte);
 extern uint8_t flash_buffer[FB_SIZE];
 uint8_t flash_submit_command(uint8_t *cmd);
 uint8_t flash_start_stream(uint16_t page, uint16_t npages, uint8_t flags);
+uint8_t flash_stream_done();
 uint8_t flash_poll(uint8_t rr);
 uint16_t flash_find_free();
 
@@ -53,4 +54,6 @@ enum {
 	FS_528   = 128, // do 528 byte pages.
 };
 
+static inline uint8_t flash_current_block() { return fs.block; }
+
 #endif
diff --git a/src/fpga.c b/src/fpga.c
index 07d549d..8b7a770 100644
--- a/src/fpga.c
+++ b/src/fpga.c
@@ -2,6 +2,7 @@
 #include "pipe.h"
 #include "fpga.h"
 #include "spi.h"
+#include <string.h>
 
 uint8_t fpga_reset_poll()
 {
@@ -12,6 +13,18 @@ uint8_t fpga_reset_poll()
 	return r;
 }
 
+uint8_t fpga_status()
+{
+	uint8_t r = fpga_power();
+	// all three altera pins must be on the same PORT
+	if (r)
+		r |= CRCERR_VPORT.IN &
+			( 1<<nCONFIG_PIN
+			| 1<<nSTATUS_PIN
+			| 1<<CRCERR_PIN );
+	return r;
+}
+
 void fpga_reset()
 {
 	nCONFIG_VPORT.OUT &=~ (1<<nCONFIG_PIN);
@@ -24,8 +37,8 @@ void fpga_cmd(struct fpga_cmd *c)
 {
 	uint8_t n = c->n;
 	uint8_t z = c->z;
-	if (fpga_reset_poll()) {
-		c->n = n | fpga_busy;
+	if (fpga_status() != as_configured) {
+		c->n = n | fpga_dead;
 		return;
 	}
 	if (n & fpga_abort && spi_abort()) {
@@ -41,7 +54,7 @@ void fpga_cmd(struct fpga_cmd *c)
 		return;
 	c->n = n | fpga_submitted;
 
-	spi_select(n & fpga_config ? SPI_CONFIG : 0);
+	spi_select(n & fpga_configure ? SPI_CONFIG : 0);
 	spi.csize = n &= fpga_size;
 	spi.zero = z & 0x80; // send 0x0000 or 0x8080
 	spi.cmd = c->d;
@@ -62,25 +75,106 @@ void fpga_cmd(struct fpga_cmd *c)
 	spi_start();
 }
 
-void fpga_start(uint8_t write)
+struct pipe_fpga_cmd pipe_fpga_cmd;
+
+uint8_t fpga_start_write()
 {
-	uint8_t mode = 0;
-	if (pipe.fpga.zero == SPI_CONFIG)
-		mode = SPI_CONFIG;
+	uint8_t mode = pipe.fpga.status & SPI_CONFIG;
 	spi_select(mode);
-	_memcopy(&spi.csize, &pipe.fpga.csize, 6);
-	spi.cmd = pipe.fpga.cmd;
 	spi.wdata = flash_buffer;
-	spi.rdata = flash_buffer;
-	uint8_t n = 64;
-	if (n > pipe.fpga.size)
-		n = pipe.fpga.size;
-	pipe.fpga.size -= n;
-	if (!n)
-		return;
-	if (write)
-		spi.wsize = n;
-	else
-		spi.rsize = n;
-	spi_start();
+	uint8_t n = 32;
+	if (pipe.fpga.count)
+		pipe.fpga.count--;
+	else {
+		uint8_t nn = pipe.fpga.size;
+		if (nn < n)
+			n = nn;
+		pipe.fpga.size -= n;
+	}
+	spi.wsize = n<<1;
+	if (n)
+		spi_start();
+	return n;
+}
+
+uint8_t fpga_start_read()
+{
+	/************************************************************
+	 * Send `counts` commands to the FPGA.
+	 * Read `size` Words from each command.
+	 * Fill the `flash_buffer` with 32 Words.
+	 * AS_CONT:
+	 *     Continue reading Words after the buffer was used.
+	 * User resets spi.fpga.val when done.
+	 * Return the number of Words to be read now.
+	 ***********************************************************/
+
+	if (spi_select(0))
+		return 0;
+	if (fpga_status() != as_configured)
+		return 0;
+	if (!pipe.fpga.val)
+		memset(flash_buffer, 0, 64);
+	uint8_t n = 64 - pipe.fpga.val;
+	if (!n)
+		return n;
+	spi.rdata = flash_buffer + pipe.fpga.val;
+	n >>= 1;
+	if (~pipe.fpga.status & AS_CONT) {
+		if (!pipe.fpga.count)
+			return 0;
+		pipe.fpga.count--;
+		spi.cmd = pipe_fpga_cmd.cmd;
+		_memcopy((void*)&spi.csize, (void*)&pipe_fpga_cmd, 6);
+		pipe.fpga.pos = 0;
+		pipe.fpga.status |= AS_CONT;
+	}
+	uint8_t nn = pipe.fpga.size - pipe.fpga.pos;
+	if (nn && nn < n)
+		n = nn;
+	pipe.fpga.pos += n;
+	if (pipe.fpga.pos == pipe.fpga.size)
+		pipe.fpga.status &=~ AS_CONT;
+	spi.rsize = n << 1;
+	pipe.fpga.val += spi.rsize;
+	spi_start();
+	return n;
+}
+
+uint8_t fpga_pipe_ready()
+{
+	/************************************************************
+	 * Return the number of valid Words read in to the buffer,
+	 * when
+	 *   - the FPGA is alive, and
+	 *   - the buffer is full, or
+	 *   - there is nothing more to read.
+	 * Reset pipe.fpga.val, when returning nonzero,
+	 * assuming those Words will be used now.
+	 ***********************************************************/
+
+	uint8_t r  = pipe.fpga.val;
+	if (fpga_status() != as_configured)
+		return 0;
+	if (r >= 64 || !pipe.fpga.count && ~pipe.fpga.status & AS_CONT)
+		pipe.fpga.val = 0;
+	else
+		r = 0;
+	return r;
+}
+
+const struct pipe pipe_config_fpga_config = {
+	.source = pipe_flash,
+	.dest = pipe_fpga,
+	.fpga = {
+		.status = AS_CONFIG,
+	},
+};
+
+void fpga_config(uint16_t page, uint16_t count)
+{
+	fpga_reset();
+	pipe = pipe_config_fpga_config;
+	pipe.fpga.count = count;
+	flash_start_stream(page, count>>8, FS_Read|FS_528);
 }
diff --git a/src/fpga.h b/src/fpga.h
index 109d992..7576d36 100644
--- a/src/fpga.h
+++ b/src/fpga.h
@@ -13,7 +13,8 @@ enum fpga_flags {
 	fpga_aborted   = 0x10,
 	fpga_busy      = 0x20,
 	fpga_submitted = 0x40,
-	fpga_config    = 0x80,
+	fpga_configure = 0x80,
+	fpga_dead      = 0x80,
 
 	fpga_wait_nonzero = 0x01,
 };
@@ -21,8 +22,21 @@ enum fpga_flags {
 void fpga_reset();
 uint8_t fpga_reset_poll();
 void fpga_cmd(struct fpga_cmd *c);
-void fpga_start(uint8_t write);
+uint8_t fpga_start_read();
+uint8_t fpga_start_write();
+uint8_t fpga_pipe_ready();
+void fpga_config(uint16_t page, uint16_t count);
 
 static inline uint8_t fpga_power() { return !!(PEN_VPORT.IN & (1<<PEN_PIN)); }
 static inline void fpga_power_on() { PEN_VPORT.OUT |= 1<<PEN_PIN; }
 static inline void fpga_power_off() { PEN_VPORT.OUT &=~ (1<<PEN_PIN); }
+
+enum fpga_status_values {
+	as_off  = 0,
+	as_on   = 1,
+	as_reset = as_on | 1<<CRCERR_PIN,
+	as_configured  = as_on | 1<<nCONFIG_PIN | 1<<nSTATUS_PIN,
+	as_crcerror = as_configured | 1<<CRCERR_PIN,
+};
+
+uint8_t fpga_status();
diff --git a/src/pipe.c b/src/pipe.c
index 4643230..edd4c60 100644
--- a/src/pipe.c
+++ b/src/pipe.c
@@ -11,51 +11,120 @@
 
 section_status(pipe) struct pipe pipe;
 
+__attribute__((noinline))
+uint8_t pipe_busy()
+{
+	// Return true if anything is due to irq
+	// call this with cli() before sei();sleep()
+	if (spi_busy_p()) return 1;
+	if (flash_poll(0) & FS_Busy) return 1;
+	if (adc_poll(0)) return 1;
+	return 0;
+}
+
 uint8_t pipe_poll()
 {
+	/************************************************************
+	 * Drive data in `flash_buffer` from `source` to `dest`
+	 * `pipe_cmd`:
+	 *     data comes and goes via cmd("B…")
+	 *     `pipe.valid` controls if a buffer was fully transfered
+	 * `pipe_flash`:
+	 *     read or write pages from,to flash
+	 *     `PS_528`: use all 528 bytes
+	 *     `PS_BCH`: compute or check the BCH codes
+	 * `pipe_adc`: (source)
+	 *      Fill the buffer with ADC readings and further status
+	 * `pipe_fpga`:
+	 *      Configure the FPGA
+	 *      Write to the FPGA
+	 *      Read from the FPGA, with commands
+	 ***********************************************************/
+
+	// Return, if
+	//    any hardware is busy,
+	//    an FS_Error occured, or
+	//    the data goes nowhere.
 	uint8_t r = pipe.status;
-	uint8_t fl = flash_poll(0);
-	if (spi_busy_p() || fl & FS_Busy || adc_poll(0))
-		goto done;
+	uint8_t dest = pipe.dest;
+
+	if (pipe_busy() || !dest)
+		return r;
 #ifdef HAVE_FPGA
-	if (fpga_reset_poll())
-		goto done;
+	// we need to wait at least until the FPGA raises nCONFIG
+	if (dest & pipe_fpga && fpga_reset_poll())
+		return r;
 #endif
+
+	uint8_t valid = pipe.valid;
+
 	if (r & PS_OUT) {
-		if (pipe.dest & pipe_cmd && pipe.valid & 0x1f)
+		// Sending the buffer to `dest`.
+		// Return if we are not done sending to all destinations.
+
+		if (dest & pipe_cmd && valid & 0x1f)
 			// cmd did not drain the buffer, yet
 			goto done;
-		if (pipe.dest & pipe_flash && !(fl & FS_Ready))
-			// flash did not finish successfully
-			goto done;
-		if (pipe.source & pipe_adc && !adc_poll(pipe.adc))
+		if (dest & pipe_flash && ~fs.status & FS_Ready)
+			// flash did not finish yet, successfully
 			goto done;
 
 		// fpga is OUT when the spi is ready.
 		// We are done with this buffer
-		pipe.valid = 0;
-		if (pipe.source & pipe_flash)
+
+		r &=~ PS_OUT;
+
+		// Return if next ADC reading is not yet due.
+		// Come back here, until is is.
+
+		if (pipe.source & pipe_adc && !adc_poll(pipe.adc))
+			goto done;
+
+		// Continue the flash stream.
+		// PS_BLK is the 64-Bytes buffer number in the page
+
+		valid = 0;
+		if (pipe.source & pipe_flash) {
+			r &= ~ PS_BLK;
+			r |= flash_current_block() & PS_BLK;
 			flash_poll(1);
+		}
 #ifdef HAVE_FPGA
-		else if (pipe.source & pipe_fpga)
-			fpga_start(0);
+		// Continue the FPGA stream.
+
+		else if (pipe.source & pipe_fpga) {
+			if (~fpga_start_read())
+				pipe.source &=~ pipe_fpga;
+		}
 #endif
-		r &=~ (PS_OUT|4);
-		r++;
 		goto done;
 	}
 
+	// Waiting for the buffer to fill
+
+	// For 528 bytes pages, the last buffer must be 80 Bytes,
+	// i.e., five cmd_buffers á 16 Bytes
 	uint8_t bflgs = 0x0f;
 	if ((r & PS_5) == PS_5)
 		bflgs = 0x1f;
 
+	// Data from the ADC is in named .bss segments. We send
+	// 16, 32, or 64 Bytes from the .bss segement for ead ADC reading.
+	// The first named .bss segment is `magic`.  Observe the link order
+	// in the Makefile.
+	//
+	// Fun with assembly.
+	// `n` is the number of bytes, [16, 32, 64]
+	// `o` is the addr in the flash_buffer
+	// `v` are the currently valid cmd_buffer flags
+	// `f` are the fresh valid cmd_buffer flags
 	if (pipe.source & pipe_adc) {
 		uint8_t n = pipe.adc & 0x70;
 		if (!n)
 			goto adc_done;
 		uint8_t f = n-1;
 		uint8_t o = -16;
-		uint8_t v = pipe.valid;
+		uint8_t v = valid;
 #if 0
 		uint8_t c;
 		do {
@@ -84,49 +153,101 @@ uint8_t pipe_poll()
 			f = 0xff;
 			n = 64-o;
 		}
-		pipe.valid |= f>>4;
+		valid |= f>>4;
 		_memcopy(flash_buffer+o, (void*)&magic, n);
 	}
 adc_done:
 
-	if (pipe.source & pipe_flash && fl & FS_Ready)
-		pipe.valid = bflgs;
+	// When the flash is done, flag the buffer valid,
+	// including BCH Bytes.
+	if (pipe.source & pipe_flash && fs.status & FS_Ready)
+		valid = bflgs;
 #ifdef HAVE_FPGA
-	else if (pipe.source & pipe_fpga)
-		pipe.valid = 0x0f;
+	// The FPGA delivers 64 Bytes.
+	else if (pipe.source & pipe_fpga && fpga_pipe_ready())
+		valid = 0x0f;
 #endif
-	if (~pipe.valid & 0x0f)
+	// The buffer is not here, yet.  Nothing we can do now.
+	if (~valid & 0x0f)
 		goto done;
+
+	// The buffer shall include BCH Bytes.
 	if (r & PS_BCH) {
-		if (!(r&3))
+		// First buffer of a page, clear the parity
+		if (!(r & PS_BLK))
 			bch4369_init(config.bch_salt);
+		// Add the current buffer to the parity
 		uint8_t *bend = bch4369_stri(flash_buffer, 64);
-		if (!(~r & 3)) {
-			// reuse Y=bend
-			_memcopyyz(bend, bch_parity, 16);
-			pipe.valid = 0x01f;
+		// Last buffer of the page:
+		if (!(~r & PS_BLK)) {
+			bch4369_fini();
+			valid = 0x01f;
+			// When the Flash is not the source,
+			// copy the computed parity into the buffer.
+			if (~pipe.source & pipe_flash)
+				_memcopyyz(bend, bch_parity, 16);
+			// When the page as read from flash has invalid parity,
+			// stop writing to the FPGA.
+			else if (_memcmpyz(bch_parity, bend, 16)) {
+				dest &=~ pipe_fpga;
+				r |= PS_ERR;
+			}
 		}
 	}
-	if (~pipe.valid & bflgs)
+	// We still do not have all data we need
+	if (~valid & bflgs)
 		goto done;
 
-#ifdef HAVE_FPGA
-	if (pipe.dest & pipe_fpga)
-		fpga_start(1);
-#endif
-
+	// The buffer is full, send it.
 	r |= PS_OUT;
+
+#ifdef HAVE_FPGA
+	// Resume the FPGA stream
+	if (dest & pipe_fpga & ~fpga_start_write())
+		dest &=~ pipe_fpga;
+	else
+#endif
+	// Resume the flash stream
+	if (dest & pipe_flash) {
+		r &= ~ PS_BLK;
+		r |= flash_current_block() & PS_BLK;
+		flash_poll(1);
+		if (flash_stream_done())
+			dest &=~ pipe_flash;
+	}
+
 done:
+	pipe.dest = dest;
+	pipe.valid = valid;
 	pipe.status = r;
 	return r;
 }
 
-void pipe_config(const struct pipe_config *c)
+void pipe_config(const struct pipe_config *c, const struct pipe_fpga_cmd *a)
 {
-	pipe = c->pipe;
-	if ((pipe.source | pipe.dest) & pipe_flash)
-		flash_start_stream(c->page, c->npages, c->flash);
+	/************************************************************
+	 * cmd("B0!", «fpga-cmd»)  optionally configure an FPGA cmd
+	 * cmd("P0:, «pipe-cfg»)    with `AS_CMD` in `.status`
+	 ***********************************************************/
+
+	if (c->pipe.dest) {
+		pipe = c->pipe;
+		if ((pipe.source | pipe.dest) & pipe_flash)
+			flash_start_stream(c->page, c->npages, c->flash);
+	}
+	else {
+		// new source (NOT flash)
+		pipe.source = c->pipe.source;
+	}
 	if (pipe.source & pipe_adc)
 		adc_start_stream(pipe.adc);
+#ifdef HAVE_FPGA
+	if (pipe.source & pipe_fpga) {
+		if (a && pipe.fpga.status & AS_CMD)
+			_memcopyzy((void*)&pipe_fpga_cmd, (void*)a, sizeof(*a));
+		else
+			memset(&pipe_fpga_cmd, 0, sizeof(*a));
+		fpga_start_read();
+	}
+#endif
 }
-
diff --git a/src/pipe.h b/src/pipe.h
index bb23d65..9d9c3f7 100644
--- a/src/pipe.h
+++ b/src/pipe.h
@@ -8,10 +8,15 @@ enum pipe_ports {
 	pipe_fpga  = 8,
 
 	PS_OUT =  0x80,
-	PS_BCH =  0x10,
-	PS_528 =  0x08,
-	PS_BLK =  0x03,
+	PS_ERR =  0x40,
+	PS_BCH =  0x20,
+	PS_528 =  0x10,
+	PS_BLK =  0x07,
 	PS_5   =  PS_BLK | PS_528, // need 16 bytes more
+
+	AS_CONT = 1,
+	AS_CONFIG = SPI_CONFIG, // = 2
+	AS_CMD =  4,
 };
 
 extern
@@ -23,14 +28,11 @@ struct pipe {
 	uint8_t adc;
 #ifdef HAVE_FPGA
 	struct {
-		uint16_t size;
-		uint8_t cmd[4];
-		uint8_t csize;
-		uint8_t zsize;
-		uint8_t isize;
-		uint8_t zero;
-		uint8_t wait;
-		uint8_t mask;
+		uint8_t status; // AS_…
+		uint16_t count; // number of cmds(read), 64 Bytes(write)
+		uint8_t size; // Words per cmd (read), extra Words (write), 0==256
+		uint8_t val; // Valid Bytes in Buffer (read)
+		uint8_t pos; // Words read from current cmd (read)
 	} fpga;
 #endif
 } pipe;
@@ -42,6 +44,18 @@ struct pipe_config {
 	uint8_t  flash;
 };
 
+extern
+struct pipe_fpga_cmd {
+	uint8_t csize;
+	uint8_t zsize;
+	uint8_t isize;
+	uint8_t zero;
+	uint8_t wait;
+	uint8_t mask;
+	uint8_t cmd[10];
+} pipe_fpga_cmd;
+
+uint8_t pipe_busy();
 uint8_t pipe_poll();
 void pipe_cron();
-void pipe_config(const struct pipe_config *c);
+void pipe_config(const struct pipe_config *c, const struct pipe_fpga_cmd *a);
diff --git a/src/spi.c b/src/spi.c
index b1425ac..85cf3fa 100644
--- a/src/spi.c
+++ b/src/spi.c
@@ -31,6 +31,11 @@ ISR(SPI0_INT_vect)
 			d = spi.zero;
 		}
 		else if (spi.wsize) {
+			// TODO:
+			// spi.csize = spi.wsize;
+			// spi.wsize = 0;
+			// spi.cmd = spi.wdata;
+			// goto repeat;
 			spi.wsize--;
 			d = *spi.wdata++;
 		}
diff --git a/src/thhor.c b/src/thhor.c
index 32f291a..e6a2869 100644
--- a/src/thhor.c
+++ b/src/thhor.c
@@ -40,8 +40,17 @@ int main()
 	send_hex_byte_eol(magic.reset_source);
 
 	while (1) {
+		// The pipe may become idle before we reach sleep.
+		// Make sure we have nothing to do before we sleep.
+		// The sleep command will execute even when an irq
+		// is pending.  It will wake us immediately.
+		cli();
+		if (!command_pending() && (!pipe.dest || pipe_busy())) {
+			sei();
+			sleep_cpu();
+		}
 		sei();
-		sleep_cpu();
 		command();
+		pipe_poll();
 	}
 }
diff --git a/src/uart.h b/src/uart.h
index 6438874..f06a422 100644
--- a/src/uart.h
+++ b/src/uart.h
@@ -26,3 +26,10 @@ void send_hex_long(uint32_t b)
 
 extern uint8_t uart_rx_err;
 extern uint8_t uart_rx_errors;
+extern volatile uint8_t uart_rx_mes;
+
+static inline
+uint8_t command_pending()
+{
+	return uart_rx_mes;
+}