Merge pull request #487 from udo-munk/dev

merge dev

doc/README-ice.txt

@@ -16,25 +16,28 @@ WANT_ICE	to enable the ICE
 WANT_TIM	to enable T-state counting
 HISIZE		to enable register history and optionally change the
 		size of the history table
-SBSIZE		to enable breakpoints and optionally change the size
-		of the breakpoints table
+SBSIZE		to enable software breakpoints and optionally change
+		the size of the breakpoints table
+WANT_HB		to enable the hardware breakpoint
 
 For cpmsim see "README-cpm.txt" on how to build it. The simulators
 which include a frontpanel (altairsim, cromemcosim, or imsaisim) need
 to be build without it, as described in "README-frontpanel.txt".
 
 The ICE also can be included when running on bare metal, if the device
-has enough memory. This is shown in picosim running on Raspberry Pi Pico.
-Because the bare metal is not running an operating system all
-commands that require one are disabled. Also this is done with the define
-in sim.h for the machine:
+has enough memory. This is shown in picosim running on a Raspberry Pi
+Pico. Because on bare metal there is no operating system all commands
+that require one are disabled. To enable bare metal support add the
+following to the sim.h file for the machine:
 
 #define BAREMETAL       /* set up the simulator core for bare metal use */
 
 Also watch out what code you are going to execute, because without an
-operating system that provides signal handling for applications, we have
-no way to break a runnaway program with CTL-C, as it works with z80sim
-on workstations. This requires at least a switch connected to an
-interrupt pin and an interrupt handler, which signals the CPU emulation
-to stop. This is implemented in picosim, also see picture of breadboard
-wiring.
+operating system that provides signal handling for applications, we
+have no way to break a runaway program with CTL-C, as it works with
+z80sim on workstations. This requires at least a switch connected to
+an interrupt pin and an interrupt handler, which signals the CPU
+emulation to stop. This is implemented in picosim, see also the
+picture of breadboard wiring. With picosim it is also possible to
+trigger an interrupt over USB with a serial line BREAK signal (for
+example, CTL-A F in minicom or CTL-Pause/Break in putty).