main: Delay before calling powerdown

Not sure why this delay is required, but without it the machine
usually just resets.  Clear the screen right away in response to the
key though so we seem responsive.

Author: jcs

crt0.s

@@ -212,8 +212,10 @@ _debug4::
 _exit::
 	call	_reboot
 
-_powerdown_mode::
-	call	#0x0a6b			; firmware powerdownmode function
+_powerdown::
+	di
+	call	#0x0a6b			; firmware powerdown function
+	jp	_panic			; in case we fail to powerdown somehow
 
 _reboot::
 	jp	0x0000

mailstation.h

@@ -93,7 +93,7 @@ extern unsigned char debug4;
 /* crt0.s */
 extern unsigned char msTERM_version;
 extern void exit(void);
-extern void powerdown_mode(void);
+extern void powerdown(void);
 extern void new_mail(unsigned char on);
 extern void reboot(void);
 extern void delay(unsigned int millis);

main.c

@@ -266,7 +266,10 @@ process_keyboard(void)
 
 	switch (b) {
 	case KEY_POWER:
-		powerdown_mode();
+		/* not sure why the delay is needed to actually power down */
+		clear_screen();
+		delay(200);
+		powerdown();
 		break;
 	case KEY_F1:
 		if (source == SOURCE_MODEM) {