byte is 1 iff there is another byte in the message.
First Second ASCII Message Brief
- Byte byte etc. name description
+ Byte byte etc. or hex name description
From host to PIC:
- > 1 0100 TTT 0 TTTTTTT POINT Point T fire
- > 1 1111 111 .... NMRADATA NMRA data
- > 1 0001 XXX 0 XXXXXXX PING Ping `X' (please Pong `X')
- > 1 0010 RRR E RRR... POLARITY Set polarity
- > 0 0100 001 ON Power on
- > 0 0100 000 OFF Power off
+ > 1 0100 TTT 0 TTTTTTT (a0) POINT Point T fire
+ > 1 1111 111 .... (ff) NMRADATA NMRA data
+ > 1 0001 XXX 0 XXXXXXX (88+) PING Ping `X' (please Pong `X')
+ > 1 0010 RRR E RRR... (90+) POLARITY Set polarity
+ > 1 0011 000 0 MMMMMMM (98+) WATCHDOG W'dog reset, t/o <M*16>ms from now
+ > 0 0010 001 (11) ON Power on
+ > 0 0010 000 (10) OFF Power off
- > 00000000 CRASHED Acknowledge panic, go to readout mode
+;> 00000000 CRASHED Acknowledge panic, go to readout mode
+;> 00001010 (0a) TELLMODE Confirm mode - say HELLO or CRASHED
+; if crashed, undoes the effect of ack
; In crash readout mode:
;
; 00000000 MS Select crash readout mode if not already
; Reset crash readout pointer to 0
;
+; 00001000 Acknowledge RS232 framing error or overrun
+; 00001001 Reboot
+;
; 1vvvvvvv M Prepare byte 0vvvvvvv for transmission to the slave
;
-; 0000nnnn M (n>0) prepare to receive nnnn bytes from slave
+; 00000nnn M (n>0) prepare to receive nnnn bytes from slave
; 0001nnnn M (n>0) transmit nnnn bytes of our own from the
; readout pointer
;
From PIC to host:
- < 1 001Y SSS 0 SSSSSSS DETECT Train is (Y=1) or is not (Y=0) at S
- < 1 0001 XXX 0 XXXXXXX PONG Pong `X' (reply to Ping `X')
+ < 1 001Y SSS 0 SSSSSSS (9?) DETECT Train is (Y=1) or is not (Y=0) at S
+ < 1 0001 XXX 0 XXXXXXX (88+) PONG Pong `X' (reply to Ping `X')
+ < 1 100 0001 0 NNNNNNN (ENQ) SPURIOUS Number of spurious fault interrupts
< 0 000 1001 (HT) HELLO I am booted
< 0 000 1011 (VT) AAARGH Followed by debug chars (only)
+ < 0 000 1101 (CR) WTIMEOUT Watchdog timeout happened
< 0 000 0111 (BEL) FAULT Fault exists
< 0 000 0110 (ACK) FIXED Fault now fixed
- < 0 0100 PPP POINTED Point change done using capacitor P
- < 0 0101 PPP CHARGED Point capacitor P is now charged
- < 0 00000 FF NMRADONE Have processed F NMRADATA message(s)
+ < 0 0100 PPP (20+) POINTED Point change done using capacitor P
+ < 0 0101 PPP (28+) CHARGED Point capacitor P is now charged
+ < 0 00000 FF NMRADONE Have processed F NMRADATA message(s)
< 0000 1010 (LF) } debugging output 0x0a (newline) and
< 001C CCCC } (works with terminal 0x20-0x7e
The host can send ON and OFF to turn the track (and various other
stuff) on and off. After ON, the track power should be enabled and
-transmitting NMRA idle, and the CDU should be enabled. (ON - or the
-things that might precede ON such as FAULT etc. - should clear the
-data from any previous NMRADATA commands.)
+transmitting NMRA idle, and the CDU should be enabled.
If the power is ON, and a track power short circuit is detected, the
PIC should send FAULT. When the short circuit is removed, the PIC
Track and CDU Track and CDU
disabled -------ON-------> enabled
- . (clears NMRA
- /|\ buffers) |
+ .
+ /|\ |
| |Short circuit detected
\ |
\FIXED FAULT
(User Fault indicator lit)
+If OFF is issued in the first 500ms following a short circuit, it will
+be ignored; if the short circuit persists, OFF during the following
+period will go to the `Track and CDU disabled' state without sending
+FIXED.
+
POINTS and CDU
--------------
is recharging <----POINTED---- Point is changing
+Note that OFF will turn the CDU off, and a short circuit (FAULT) will
+turn it off 500ms later (this delay avoids losing races where the host
+sends a point change instruction just before a short happens).
+
PING and PONG
-------------
ignored by the PICs. The host must send exactly as many bytes as are
necessary to include all of the reversal segments for each reversers
board (for every potential reversal segment, regardless of whether
-that segment is a defined segment corresponding to some actual track).
+that segment is a defined segment corresponding to some actual track;
+however a board with _no_ reversers segments used does not count).
For example, if there are 14 reversible segments (numbered 1 to 14)
then the following message