From ea6971b809eae9ca238cd859316fdcef2839b002 Mon Sep 17 00:00:00 2001
From: Leo C <erbl259-lmu@yahoo.de>
Date: Tue, 25 Nov 2014 10:53:39 +0100
Subject: [PATCH] Timeout for Z180 bus access

---
 avr/cmd_boot.c   |   7 +-
 avr/cmd_mem.c    |  58 ++++++++----
 avr/z80-if.c     | 232 +++++++++++++++++++++++++++++++----------------
 include/z80-if.h |   7 +-
 4 files changed, 202 insertions(+), 102 deletions(-)

diff --git a/avr/cmd_boot.c b/avr/cmd_boot.c
index 2c3a533..4775b6e 100644
--- a/avr/cmd_boot.c
+++ b/avr/cmd_boot.c
@@ -34,7 +34,7 @@ static void z80_load_mem(void)
 				hdrom_length_of_sections[sec]);
 
 		z80_bus_cmd(Request);
-		z80_write_block((const FLASH unsigned char *) &hdrom[sec_base],  /* src */
+		z80_write_block_P((const FLASH unsigned char *) &hdrom[sec_base],  /* src */
 				hdrom_address[sec],                  /* dest */
 				hdrom_length_of_sections[sec]);      /* len */
 		z80_bus_cmd(Release);
@@ -176,7 +176,7 @@ command_ret_t do_console(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv
 //	uint8_t help_prompt = 0;
 	uint8_t code = 0;
 	uint8_t state = 0;
-	
+
 	(void) cmdtp; (void) flag; (void) argc; (void) argv;
 
 
@@ -198,7 +198,7 @@ command_ret_t do_console(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv
 					/* TODO: Timer starten */
 				} else {
 					z80_memfifo_putc(fifo_conin, ch);
-				}	
+				}
 				break;
 			case 2:
 				printf_P(PSTR("\n"
@@ -272,4 +272,3 @@ command_ret_t do_console(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv
 quit:
 	return CMD_RET_SUCCESS;
 }
-	
diff --git a/avr/cmd_mem.c b/avr/cmd_mem.c
index 66ace10..0bc5742 100644
--- a/avr/cmd_mem.c
+++ b/avr/cmd_mem.c
@@ -41,10 +41,10 @@ static	uint32_t	base_address = 0;
 
 void z180_read_buf(uint8_t *buf, uint32_t addr, uint8_t count)
 {
-		z80_bus_cmd(Request);
-		while (count--)
-			*buf++ = z80_read(addr++);
-		z80_bus_cmd(Release);
+		if (z80_bus_cmd(Request) & ZST_ACQUIRED) {
+			z80_read_block (buf, addr, count);
+			z80_bus_cmd(Release);
+		}
 }
 
 /*--------------------------------------------------------------------------*/
@@ -132,10 +132,13 @@ mod_mem(cmd_tbl_t *cmdtp, int incrflag, int flag, int argc, char * const argv[])
 	 * the next value.  A non-converted value exits.
 	 */
 	do {
-		z80_bus_cmd(Request);
+		if (!(z80_bus_cmd(Request) & ZST_ACQUIRED)) {
+			my_puts_P(PSTR("Bus timeout\n"));
+			return  CMD_RET_FAILURE;
+		}
 		data = z80_read(addr);
-		printf_P(PSTR("%05lx: %02x"), addr, data);
 		z80_bus_cmd(Release);
+		printf_P(PSTR("%05lx: %02x"), addr, data);
 
 		nbytes = cli_readline(PSTR(" ? "));
 		if (nbytes == 0 || (nbytes == 1 && console_buffer[0] == '-')) {
@@ -151,7 +154,10 @@ mod_mem(cmd_tbl_t *cmdtp, int incrflag, int flag, int argc, char * const argv[])
 			data = strtoul(console_buffer, &endp, 16);
 			nbytes = endp - console_buffer;
 			if (nbytes) {
-				z80_bus_cmd(Request);
+				if (!(z80_bus_cmd(Request) & ZST_ACQUIRED)) {
+					my_puts_P(PSTR("Bus timeout\n"));
+					return  CMD_RET_FAILURE;
+				}
 				z80_write(addr, data);
 				z80_bus_cmd(Release);
 				if (incrflag)
@@ -201,11 +207,11 @@ command_ret_t do_mem_mw(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[
 		count = 1;
 	}
 
-	z80_bus_cmd(Request);
-	while (count-- > 0) {
-		z80_write(addr, writeval);
-		++addr;
+	if (!(z80_bus_cmd(Request) & ZST_ACQUIRED)) {
+		my_puts_P(PSTR("Bus timeout\n"));
+		return  CMD_RET_FAILURE;
 	}
+	z80_memset(addr, writeval, count);
 	z80_bus_cmd(Release);
 
 	return CMD_RET_SUCCESS;
@@ -289,7 +295,11 @@ command_ret_t do_mem_cmp(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv
 	count = strtoul(argv[3], NULL, 16);
 
 	for (ngood = 0; ngood < count; ++ngood) {
-		z80_bus_cmd(Request);
+		if (!(z80_bus_cmd(Request) & ZST_ACQUIRED)) {
+			my_puts_P(PSTR("Bus timeout\n"));
+			rcode =  CMD_RET_FAILURE;
+			break;
+		}
 		byte1 = z80_read(addr1);
 		byte2 = z80_read(addr2);
 		z80_bus_cmd(Release);
@@ -345,7 +355,10 @@ command_ret_t do_mem_cp(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[
 
 	while (count-- > 0) {
 		uint8_t data;
-		z80_bus_cmd(Request);
+		if (!(z80_bus_cmd(Request) & ZST_ACQUIRED)) {
+			my_puts_P(PSTR("Bus timeout\n"));
+			return  CMD_RET_FAILURE;
+		}
 		data = z80_read(src);
 		z80_write(dest, data);
 		z80_bus_cmd(Release);
@@ -398,13 +411,19 @@ command_ret_t do_mem_loop(cmd_tbl_t *cmdtp, int flag, int argc,
 	 * If we have only one object, just run infinite loops.
 	 */
 	if (length == 1) {
-		z80_bus_cmd(Request);
+		if (!(z80_bus_cmd(Request) & ZST_ACQUIRED)) {
+			my_puts_P(PSTR("Bus timeout\n"));
+			return  CMD_RET_FAILURE;
+		}
 		for (;;)
 			z80_read(addr);
 		z80_bus_cmd(Release);
 	}
 
-	z80_bus_cmd(Request);
+	if (!(z80_bus_cmd(Request) & ZST_ACQUIRED)) {
+		my_puts_P(PSTR("Bus timeout\n"));
+		return  CMD_RET_FAILURE;
+	}
 	for (;;) {
 		uint32_t i = length;
 		uint32_t p = addr;
@@ -440,11 +459,18 @@ command_ret_t do_mem_loopw (cmd_tbl_t *cmdtp, int flag, int argc, char * const a
 	 * If we have only one object, just run infinite loops.
 	 */
 	if (length == 1) {
-		z80_bus_cmd(Request);
+		if (!(z80_bus_cmd(Request) & ZST_ACQUIRED)) {
+			my_puts_P(PSTR("Bus timeout\n"));
+			return  CMD_RET_FAILURE;
+		}
 		for (;;)
 			z80_write(addr, data);
 	}
 
+	if (!(z80_bus_cmd(Request) & ZST_ACQUIRED)) {
+		my_puts_P(PSTR("Bus timeout\n"));
+		return  CMD_RET_FAILURE;
+	}
 	for (;;) {
 		uint32_t i = length;
 		uint32_t p = addr;
diff --git a/avr/z80-if.c b/avr/z80-if.c
index 4544997..cc0bab1 100644
--- a/avr/z80-if.c
+++ b/avr/z80-if.c
@@ -2,57 +2,58 @@
  *
  * Pin assignments
  *
- * | Z180-Sig	|   AVR-Port	| Dir	|   Special Function	|
+ * | Z180-Sig   |   AVR-Port    | Dir   |   Special Function    |
  * +------------+---------------+-------+-----------------------+
- * |	A0	| PA 	0	|  O	|			|
- * |	A1	| PA 	1	|  O	|			|
- * |	A2	| PA 	2	|  O	|			|
- * |	A3	| PA 	3	|  O	|			|
- * |	A4	| PA 	4	|  O	|			|
- * |	A5	| PA 	5	|  O	|			|
- * |	A6	| PA 	6	|  O	|			|
- * |	A7	| PA 	7	|  O	|			|
- * |	A8	| PC 	0	|  O	|			|
- * |	A9	| PC 	1	|  O	|			|
- * |	A10	| PC 	2	|  O	|			|
- * |	A11	| PC 	3	|  O	|			|
- * |	A12	| PC 	4	|  O	|			|
- * |	A13	| PC 	5	|  O	|			|
- * |	A14	| PC 	6	|  O	|			|
- * |	A15	| PC 	7	|  O	|			|
- * |	A16	| PE 	2	|  O	|			|
- * |	A17	| PE 	3	|  O	|			|
- * |	A18	| PE 	4	|  O	|			|
- * |	D0	| PF 	0	|  I/O	|			|
- * |	D1	| PF 	1	|  I/O	|			|
- * |	D2	| PF 	2	|  I/O	|			|
- * |	D3	| PF 	3	|  I/O	|			|
- * |	D4	| PF 	4	|  I/O	|			|
- * |	D5	| PF 	5	|  I/O	|			|
- * |	D6	| PF 	6	|  I/O	|			|
- * |	D7	| PF 	7	|  I/O	|			|
- * |	RD	| PD 	3	|  O	|			|
- * |	WR	| PD 	2	|  O	|			|
- * |	MREQ	| PD 	4	|  O	|			|
- * |	RST	| PD 	5	|  O	|			|
- * |	BUSREQ	| PD 	7	|  O	|			|
- * |	BUSACK	| PD 	6	|  I	|			|
- * |	IOCS1	| PE 	5	|  I	|			|
- * |*	HALT	| P 		|	|			|
- * |*	NMI	| P 		|	|			|
- * |		| P 		|  	|			|
- * |		| P 		|  	|  af1	 USART1_TX	|
- * |		| P 		|  	|  af1	 USART1_RX	|
- * |		| P 		|JTDI	|  remap SPI1_NSS'	|
- * |		| P 		|JTDO	|  remap SPI1_SCK'	|
- * |		| P 		|JTRST	|  remap SPI1_MISO'	|
- * |		| P 		|	|  remap SPI1_MOSI'	|
- * |		| P 		|	|  af1	 OSC32		|
- * |		| P 		|	|  af1	 OSC32		|
+ * |    A0      | PA    0       |  O    |                       |
+ * |    A1      | PA    1       |  O    |                       |
+ * |    A2      | PA    2       |  O    |                       |
+ * |    A3      | PA    3       |  O    |                       |
+ * |    A4      | PA    4       |  O    |                       |
+ * |    A5      | PA    5       |  O    |                       |
+ * |    A6      | PA    6       |  O    |                       |
+ * |    A7      | PA    7       |  O    |                       |
+ * |    A8      | PC    0       |  O    |                       |
+ * |    A9      | PC    1       |  O    |                       |
+ * |    A10     | PC    2       |  O    |                       |
+ * |    A11     | PC    3       |  O    |                       |
+ * |    A12     | PC    4       |  O    |                       |
+ * |    A13     | PC    5       |  O    |                       |
+ * |    A14     | PC    6       |  O    |                       |
+ * |    A15     | PC    7       |  O    |                       |
+ * |    A16     | PE    2       |  O    |                       |
+ * |    A17     | PE    3       |  O    |                       |
+ * |    A18     | PE    4       |  O    |                       |
+ * |    D0      | PF    0       |  I/O  |                       |
+ * |    D1      | PF    1       |  I/O  |                       |
+ * |    D2      | PF    2       |  I/O  |                       |
+ * |    D3      | PF    3       |  I/O  |                       |
+ * |    D4      | PF    4       |  I/O  |                       |
+ * |    D5      | PF    5       |  I/O  |                       |
+ * |    D6      | PF    6       |  I/O  |                       |
+ * |    D7      | PF    7       |  I/O  |                       |
+ * |    RD      | PD    3       |  O    |                       |
+ * |    WR      | PD    2       |  O    |                       |
+ * |    MREQ    | PD    4       |  O    |                       |
+ * |    RST     | PD    5       |  O    |                       |
+ * |    BUSREQ  | PD    7       |  O    |                       |
+ * |    BUSACK  | PD    6       |  I    |                       |
+ * |    IOCS1   | PE    5       |  I    |                       |
+ * |*   HALT    | P             |       |                       |
+ * |*   NMI     | P             |       |                       |
+ * |            | P             |       |                       |
+ * |            | P             |       |  af1   USART1_TX      |
+ * |            | P             |       |  af1   USART1_RX      |
+ * |            | P             |JTDI   |  remap SPI1_NSS'      |
+ * |            | P             |JTDO   |  remap SPI1_SCK'      |
+ * |            | P             |JTRST  |  remap SPI1_MISO'     |
+ * |            | P             |       |  remap SPI1_MOSI'     |
+ * |            | P             |       |  af1   OSC32          |
+ * |            | P             |       |  af1   OSC32          |
 
 
  */
 
+
 #include "common.h"
 #include <util/atomic.h>
 #include "debug.h"
@@ -117,6 +118,9 @@
 //#define Z80_I_HALT	SBIT(P_HALT, )
 
 
+#define BUS_TO 20
+
+
 #define MASK(n)	((1<<(n))-1)
 #define SMASK(w,s) (MASK(w) << (s))
 
@@ -129,6 +133,20 @@ typedef union {
 
 
 static zstate_t zstate;
+static volatile uint8_t timer;		/* used for bus timeout */
+
+/*---------------------------------------------------------*/
+/* 10Hz timer interrupt generated by OC4A                  */
+/*---------------------------------------------------------*/
+
+ISR(TIMER4_COMPA_vect)
+{
+
+	uint8_t i = timer;
+
+	if (i)
+		timer = i - 1;
+}
 
 /*--------------------------------------------------------------------------*/
 
@@ -207,6 +225,13 @@ void z80_setup_bus(void)
 	z80_dbus_set_in();
 
 	zstate = RESET;
+
+	/* Timer 4 */
+	PRR1 &= ~_BV(PRTIM4);
+	OCR4A = F_CPU / 1024 / 10 - 1;		  /* Timer: 10Hz interval (OC4A) */
+	TCCR4B = (0b01<<WGM42)|(0b101<<CS30); /* CTC Mode, Prescaler 1024 */
+	TIMSK4 = _BV(OCIE4A);				  /* Enable oca interrupt */
+
 }
 
 
@@ -228,40 +253,42 @@ static void z80_busreq_hpulse(void)
 	}
 
 	if (zstate & ZST_ACQUIRED) {
-		while(Z80_I_BUSACK == 1)
+		timer = BUS_TO;
+		while (Z80_I_BUSACK == 1 && timer)
 			;
-		z80_addrbus_set_active();
+		if (Z80_I_BUSACK == 0)
+			z80_addrbus_set_active();
 	}
 }
 
 
 /*
 
- +              |		|		|		|		|
+ +              |               |               |               |               |
     +   State   |     RESET     |  RESET_AQRD   |    RUNNING    | RUNNING_AQRD  |
-       +        |		|		|		|		|
-          +     |	0	|	1	|	2	|	3	|
-Event        +  |		|		|		|		|
+       +        |               |               |               |               |
+          +     |       0       |       1       |       2       |       3       |
+Event        +  |               |               |               |               |
 ----------------+---------------+---------------+---------------+---------------+
-		|		|		|		|		|
-Reset		|	0	|	0	|	0	|	0	|
-		|		|		|		|		|
-		|		|		|		|		|
-Request		|	1	|		|	3	|		|
-		|		|		|		|		|
-		|		|		|		|		|
-Release		|		|	0	|		|	2	|
-		|		|		|		|		|
-		|		|		|		|		|
-Run		|	2	|	3	|		|		|
-		|		|		|		|		|
-		|		|		|		|		|
-Restart		|		|		|	2	|	3	|
-		|		|		|		|		|
-		|		|		|		|		|
-M_Cycle		|		|		|		|	3	|
-		|		|		|		|		|
-		|		|		|		|		|
+                |               |               |               |               |
+Reset           |       0       |       0       |       0       |       0       |
+                |               |               |               |               |
+                |               |               |               |               |
+Request         |       1       |               |       3       |               |
+                |               |               |               |               |
+                |               |               |               |               |
+Release         |               |       0       |               |       2       |
+                |               |               |               |               |
+                |               |               |               |               |
+Run             |       2       |       3       |               |               |
+                |               |               |               |               |
+                |               |               |               |               |
+Restart         |               |               |       2       |       3       |
+                |               |               |               |               |
+                |               |               |               |               |
+M_Cycle         |               |               |               |       3       |
+                |               |               |               |               |
+                |               |               |               |               |
 */
 
 zstate_t z80_bus_cmd(bus_cmd_t cmd)
@@ -281,18 +308,29 @@ zstate_t z80_bus_cmd(bus_cmd_t cmd)
 		case RESET:
 			Z80_O_BUSREQ = 0;
 			Z80_O_RST = 1;
-			while(Z80_I_BUSACK == 1)
+			timer = BUS_TO;
+			while (Z80_I_BUSACK == 1 && timer)
 				;
-			z80_addrbus_set_active();
-			zstate = RESET_AQRD;
+			if (Z80_I_BUSACK == 0) {
+				z80_addrbus_set_active();
+				zstate = RESET_AQRD;
+			} else {
+				Z80_O_RST = 0;
+				Z80_O_BUSREQ = 1;
+			}
 			break;
 
 		case RUNNING:
 			Z80_O_BUSREQ = 0;
-			while(Z80_I_BUSACK == 1)
+			timer = BUS_TO;
+			while (Z80_I_BUSACK == 1 && timer)
 				;
-			z80_addrbus_set_active();
-			zstate = RUNNING_AQRD;
+			if (Z80_I_BUSACK == 0) {
+				z80_addrbus_set_active();
+				zstate = RUNNING_AQRD;
+			} else {
+				Z80_O_BUSREQ = 1;
+			}
 			break;
 
 		default:
@@ -353,7 +391,7 @@ zstate_t z80_bus_cmd(bus_cmd_t cmd)
 	case M_Cycle:
 		switch (zstate) {
 		case RUNNING_AQRD:
-			z80_busreq_hpulse();
+			z80_busreq_hpulse();	/* TODO: */
 			break;
 		default:
 			break;
@@ -411,8 +449,25 @@ void z80_memset(uint32_t addr, uint8_t data, uint32_t length)
 {
 	z80_dbus_set_out();
 	Z80_O_MREQ = 0;
+	P_DB = data;
 	while(length--) {
 		z80_setaddress(addr++);
+		Z80_O_WR = 0;
+		Z80_O_WR = 0;
+		Z80_O_WR = 1;
+	}
+	Z80_O_MREQ = 1;
+}
+
+void z80_write_block_P(const FLASH uint8_t *src, uint32_t dest, uint32_t length)
+{
+	uint8_t data;
+
+	z80_dbus_set_out();
+	Z80_O_MREQ = 0;
+	while(length--) {
+		z80_setaddress(dest++);
+		data = *src++;
 		P_DB = data;
 		P_DB = data;
 		Z80_O_WR = 0;
@@ -422,7 +477,7 @@ void z80_memset(uint32_t addr, uint8_t data, uint32_t length)
 	Z80_O_MREQ = 1;
 }
 
-void z80_write_block(const __flash uint8_t *src, uint32_t dest, uint32_t length)
+void z80_write_block(const uint8_t *src, uint32_t dest, uint32_t length)
 {
 	uint8_t data;
 
@@ -440,6 +495,25 @@ void z80_write_block(const __flash uint8_t *src, uint32_t dest, uint32_t length)
 	Z80_O_MREQ = 1;
 }
 
+void z80_read_block (uint8_t *dest, uint32_t src, size_t length)
+{
+	uint8_t data;
+
+	Z80_O_MREQ = 0;
+	z80_dbus_set_in();
+	while(length--) {
+		z80_setaddress(src++);
+		Z80_O_RD = 0;
+		Z80_O_RD = 0;
+		Z80_O_RD = 0;
+		data = PIN_DB;
+		Z80_O_RD = 1;
+		*dest++ = data;
+	}
+	Z80_O_MREQ = 1;
+}
+
+
 /*
   0179'                         rx.bs_mask:	ds	1		; (buf_len - 1)
   017A'                         rx.in_idx:	ds	1		;
diff --git a/include/z80-if.h b/include/z80-if.h
index 24fda5d..d4ee57b 100644
--- a/include/z80-if.h
+++ b/include/z80-if.h
@@ -31,11 +31,13 @@ int z80_stat_halt(void);
 void z80_write(uint32_t addr, uint8_t data);
 uint8_t z80_read(uint32_t addr);
 void z80_memset(uint32_t addr, uint8_t data, uint32_t length);
-void z80_write_block(const FLASH uint8_t *src, uint32_t dest, uint32_t length);
+void z80_write_block_P(const FLASH uint8_t *src, uint32_t dest, uint32_t length);
+void z80_write_block(const uint8_t *src, uint32_t dest, uint32_t length);
+void z80_read_block (uint8_t *dest, uint32_t src, size_t length);
 
 
 typedef enum fifo_t {
-		fifo_msgin, fifo_msgout, 
+		fifo_msgin, fifo_msgout,
 		fifo_conout, fifo_conin,
 		NUM_FIFOS
 	} fifo_t;
@@ -46,4 +48,3 @@ int z80_memfifo_is_full(const fifo_t f);
 int z80_memfifo_getc(const fifo_t f);
 uint8_t z80_memfifo_getc_wait(const fifo_t f);
 void z80_memfifo_putc(fifo_t f, uint8_t val);
-
-- 
2.39.2