From 3a5f3735baadbf9bdf14130ce2fbb604b8f1db13 Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@urclocks.com>
Date: Sat, 26 Nov 2022 12:54:42 +0000
Subject: [PATCH] Adapt urclock_getsync() to consider legacy bootloaders
---
src/urclock.c | 86 +++++++++++++++++++++++++++++++++++++++------------
1 file changed, 66 insertions(+), 20 deletions(-)
diff --git a/src/urclock.c b/src/urclock.c
index 3e03f193..f4b90214 100644
--- a/src/urclock.c
+++ b/src/urclock.c
@@ -308,7 +308,8 @@ typedef struct {
nofilename, // Don't store application filename when writing the application
nodate, // Don't store application filename and no date either
nometadata, // Don't store any metadata at all (implies no store support)
- delay; // Additional delay [ms] after resetting the board, can be negative
+ delay, // Additional delay [ms] after resetting the board, can be negative
+ strict; // Use strict synchronisation protocol
char title[254]; // Use instead of filename for metadata - same size as filename
char iddesc[64]; // Location of Urclock ID, eg F.12324.6 or E.-4.4 (default E.257.6)
@@ -1153,6 +1154,7 @@ static void guessblstart(const PROGRAMMER *pgm, const AVRPART *p) {
{ 256, 0, 0x1451061b, 0x1451061b }, // picobootArduino168v3b2.hex
{ 512, 0, 0x3242ddd3, 0x53348738 }, // picobootArduino328.hex
{ 512, 0, 0x858e12de, 0xc80a44a4 }, // picobootArduino328v3beta.hex
+ { 512, 0, 0x3242ddd3, 0xc254e344 }, // picobootArduino328v3b2.hex
{ 256, 0, 0xaa62bafc, 0xaa62bafc }, // picobootArduino8v3rc1.hex
{ 256, 0, 0x56263965, 0x56263965 }, // picobootSTK500-168p.hex
{ 512, 0, 0x3242ddd3, 0x5ba5f5f6 }, // picobootSTK500-328p.hex
@@ -1870,7 +1872,7 @@ static int urclock_recv(const PROGRAMMER *pgm, unsigned char *buf, size_t len) {
rv = serial_recv(&pgm->fd, buf, len);
if(rv < 0) {
if(!ur.sync_silence)
- pmsg_warning("programmer is not responding%s\n", ur.uP.name? "": "; try, eg, -xdelay=200");
+ pmsg_error("programmer is not responding; try and vary -xdelay=100 and/or -xstrict\n");
return -1;
}
@@ -1878,7 +1880,7 @@ static int urclock_recv(const PROGRAMMER *pgm, unsigned char *buf, size_t len) {
}
-#define MAX_SYNC_ATTEMPTS 23
+#define MAX_SYNC_ATTEMPTS 16
/*
* The modified protocol makes stk_insync and stk_ok responses variable but fixed for a single
@@ -1887,37 +1889,78 @@ static int urclock_recv(const PROGRAMMER *pgm, unsigned char *buf, size_t len) {
* sync until the stk_insync/ok responses coincide with the the most recent responses.
*/
static int urclock_getsync(const PROGRAMMER *pgm) {
- unsigned char iob[2];
+ unsigned char iob[2], autobaud_sync;
int attempt;
+ AVRPART *part;
// Reduce timeout for establishing comms
- serial_recv_timeout = 80; // ms
+ serial_recv_timeout = 10; // ms
+ part = partdesc? locate_part(part_list, partdesc): NULL;
+ /*
+ * The urboot autosync detection uses a loop
+ *
+ * 2: adiw r26, 32
+ * sbis RX_Pin_Port,RX_Bit
+ * rjmp 2
+ *
+ * The number of cycles in this loop must be the position of the least significant set bit of the
+ * first byte sent by AVRDUDE. For a 5-cycle loop (ATmega*) the fifth-lowest bit must be set and
+ * the four least significant bit unset, eg, 0x30, which by coincidence is Cmnd_STK_GET_SYNC. For
+ * ATxmega* parts, the sync byte could be 0x20. For LGT8F* parts this loop has three cycles, so
+ * 0x1c would be appropriate. Care must be taken to not choose a sync byte that is an otherwise
+ * legitimate command, ie nothing avove 0x30 or below 0x10 should be chosen.
+ */
+ autobaud_sync = part && part->autobaud_sync? part->autobaud_sync: Cmnd_STK_GET_SYNC;
ur.sync_silence = 1;
- iob[0] = Cmnd_STK_GET_SYNC; // Initial sync for autobaud - drain response
- iob[1] = Sync_CRC_EOP;
- urclock_send(pgm, iob, 2);
- serial_drain(&pgm->fd, 0);
for(attempt = 0; attempt < MAX_SYNC_ATTEMPTS; attempt++) {
- iob[0] = Cmnd_STK_GET_SYNC;
+ /*
+ * The initial byte for autobaud must be the sync byte/Sync_CRC_EOP sequence; thereafter it
+ * should normally be Cmnd_STK_GET_SYNC/Sync_CRC_EOP. However, both urboot and optiboot are
+ * "permissive" as to the get sync command: anything that is not a valid, known command is
+ * acceptable. However, these are less permissive when it comes to the End of command byte
+ * Sync_CRC_EOP: if that is wrong the bootloader swiftly enters the application. Old but
+ * popular optiboot v4.4 first initialises the USART and *then* entertains the user for 300 ms
+ * with a flashing LED, which means that AVRDUDE's initial 2-byte sync sequence will appear as
+ * one byte Sync_CRC_EOP (because the first byte is overwritten) getting the communication out
+ * of step through a missing byte. If AVRDUDE then sends the next request starting with a
+ * Cmnd_STK_GET_SYNC command then optiboot v4.4 will bail as ist's not Sync_CRC_EOP. Hence, the
+ * strategy here is to send Sync_CRC_EOP/Sync_CRC_EOP for getting a sync. For those bootloaders
+ * that are strict about the protocol, eg, picoboot, the presence of -xstrict implies that
+ * comms should use Cmnd_STK_GET_SYNC for getting in sync.
+ */
+ iob[0] = attempt == 0? autobaud_sync: ur.strict? Cmnd_STK_GET_SYNC: Sync_CRC_EOP;
iob[1] = Sync_CRC_EOP;
urclock_send(pgm, iob, 2);
if(urclock_recv(pgm, iob, 2) == 0) { // Expect bootloader to respond with two bytes
if(!ur.gs.seen || iob[0] != ur.gs.stk_insync || iob[1] != ur.gs.stk_ok || iob[0] == iob[1]) {
ur.gs.stk_insync = iob[0];
ur.gs.stk_ok = iob[1];
- if(ur.gs.seen)
- serial_drain(&pgm->fd, 0);
ur.gs.seen = 1;
} else
break;
+ } else { // Board not yet out of reset or bootloader twiddles lights
+ int slp = 32<<(attempt<3? attempt: 3);
+ pmsg_debug("%4d ms: sleeping for %d ms\n", avr_mstimestamp(), slp);
+ usleep(slp*1000);
}
- if(attempt > 2) { // Don't report first three attempts
+ if(attempt > 5) { // Don't report first six attempts
ur.sync_silence = 0;
- pmsg_warning("attempt %d of %d: not in sync\n", attempt - 2, MAX_SYNC_ATTEMPTS-3);
+ pmsg_warning("attempt %d of %d: not in sync\n", attempt - 5, MAX_SYNC_ATTEMPTS-6);
}
}
+
+ if(!ur.strict) { // Could be out of step by one byte
+ iob[0] = Sync_CRC_EOP;
+ urclock_send(pgm, iob, 1); // If so must send EOP
+ if(urclock_recv(pgm, iob, 1) < 0) {
+ iob[0] = Sync_CRC_EOP; // No reply: we were not out of step, but are now
+ urclock_send(pgm, iob, 1); // So, send the concluding byte
+ }
+ }
+ serial_drain(&pgm->fd, 0); // And either way drain the reply
+
ur.sync_silence = 0;
serial_recv_timeout = 500; // ms
@@ -1943,7 +1986,7 @@ static int urclock_getsync(const PROGRAMMER *pgm) {
ur.urfeatures = UB_FEATURES(bootinfo);
ur.urprotocol = 1;
- set_uP(pgm, partdesc? locate_part(part_list, partdesc): NULL, mcuid, 1);
+ set_uP(pgm, part, mcuid, 1);
if(!ur.uP.name)
Return("cannot identify MCU");
if(!partdesc) // Provide partdesc info, so user does not have to set it
@@ -2148,15 +2191,17 @@ static int urclock_open(PROGRAMMER *pgm, const char *port) {
// Set DTR and RTS back to high
serial_set_dtr_rts(&pgm->fd, 1);
- if((80+ur.delay) > 0)
- usleep((80+ur.delay)*1000); // Wait until board comes out of reset
+ if((110+ur.delay) > 0)
+ usleep((110+ur.delay)*1000); // Wait until board comes out of reset
// Drain any extraneous input
- serial_drain_timeout = 80; // ms
+ serial_drain_timeout = 20; // ms
serial_drain(&pgm->fd, 0);
+ pmsg_debug("%4d ms: enter urclock_getsync()\n", avr_mstimestamp());
if(urclock_getsync(pgm) < 0)
return -1;
+ pmsg_debug("%4d ms: all good, ready to rock\n", avr_mstimestamp());
return 0;
}
@@ -2372,6 +2417,7 @@ static int urclock_parseextparms(const PROGRAMMER *pgm, LISTID extparms) {
{"nodate", &ur.nodate, NA, "Do not store application filename and no date either"},
{"nometadata", &ur.nometadata, NA, "Do not store metadata at all (ie, no store support)"},
{"delay", &ur.delay, ARG, "Add delay [ms] after reset, can be negative"},
+ {"strict", &ur.strict, NA, "Use strict synchronisation protocol"},
{"help", &help, NA, "Show this help menu and exit"},
};
@@ -2397,11 +2443,11 @@ static int urclock_parseextparms(const PROGRAMMER *pgm, LISTID extparms) {
char *end;
long ret = strtol(arg, &end, 0);
if(*end || end == arg) {
- pmsg_error("cannot parse -x%s\n", arg);
+ pmsg_error("cannot parse -x%s\n", extended_param);
return -1;
}
if((int) ret != ret) {
- pmsg_error("out of integer range -x%s\n", arg);
+ pmsg_error("out of integer range -x%s\n", extended_param);
return -1;
}
*options[i].optionp = ret;