]> cloudbase.mooo.com Git - z180-stamp.git/blobdiff - avr/z80-if.c
Bugfix z80_addrbus_set_tristate()
[z180-stamp.git] / avr / z80-if.c
index 955a61a034c02ca1c87242a9f0d53bd1f9777ddb..c49d2146c9e63b058ccb5a2d63ec7b4e4ba4cfd2 100644 (file)
@@ -1,89 +1,74 @@
+/*
+ * (C) Copyright 2014 Leo C. <erbl259-lmu@yahoo.de>
+ *
+ * SPDX-License-Identifier:    GPL-2.0+
+ */
+
 /**
  *
  * 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 <avr/io.h>
-#include <util/delay.h>
-#include <stdio.h>
+
+#include "common.h"
+#include <util/atomic.h>
 #include "debug.h"
 #include "z80-if.h"
 
 
-/* Number of array elements */
-#define NELEMS(x)  (sizeof x/sizeof *x)
-
-
-#define CONCAT(x,y) x ## y
-#define EVALUATOR(x,y)  CONCAT(x,y)
-
-#define GPIO_(X)       CONCAT(GPIO, X)
-
-struct bits {
-  uint8_t b0:1;
-  uint8_t b1:1;
-  uint8_t b2:1;
-  uint8_t b3:1;
-  uint8_t b4:1;
-  uint8_t b5:1;
-  uint8_t b6:1;
-  uint8_t b7:1;
-} __attribute__((__packed__));
-
-#define SBIT(port,pin) ((*(volatile struct bits*)&port).b##pin)
-
-
 
+//#define P_ZCLK               PORTB
+//#define ZCLK         5
+//#define DDR_ZCLK     DDRB
 #define P_MREQ         PORTD
 #define MREQ           4
 #define DDR_MREQ       DDRD
@@ -95,6 +80,7 @@ struct bits {
 #define BUSREQ         7
 #define DDR_BUSREQ     DDRD
 #define P_BUSACK       PORTD
+#define PIN_BUSACK     PIND
 #define BUSACK         6
 #define DDR_BUSACK     DDRD
 //#define P_HALT               PORTA
@@ -117,8 +103,8 @@ struct bits {
 #define P_ADH          PORTC
 #define P_ADB          PORTE
 #define PIN_ADB                PINE
-#define DDR_ADL                DDRE
-#define DDR_ADH                DDRE
+#define DDR_ADL                DDRA
+#define DDR_ADH                DDRC
 #define DDR_ADB                DDRE
 
 #define ADB_WIDTH      3
@@ -126,187 +112,321 @@ struct bits {
 //#define ADB_PORT     PORTE
 
 
-
-#define ADp1_OFS       0
-#define ADp1_WIDTH     8
-#define ADp1_SHIFT     1
-#define ADp1_PORT      GPIOA
-
-#define ADp2_OFS       ADp1_WIDTH
-#define ADp2_WIDTH     8
-#define ADp2_SHIFT     0
-#define ADp2_PORT      GPIOC
-
-#define ADp3_OFS       (ADp2_OFS+ADp2_WIDTH)
-#define ADp3_WIDTH     3
-#define ADp3_SHIFT     10
-#define ADp3_PORT      GPIOC
-
-#define ADunbuff1_WIDTH        1
-#define ADunbuff1_SHIFT        8
-#define ADunbuff1_PORT GPIOA
-
-#define ADunbuff2_WIDTH        2
-#define ADunbuff2_SHIFT        6
-#define ADunbuff2_PORT GPIOC
-
-#define ADunbuff3_WIDTH        3
-#define ADunbuff3_SHIFT        10
-#define ADunbuff3_PORT GPIOC
-
-#define DB_OFS         0
-#define DB_WIDTH       8
-#define DB_SHIFT       8
-#define DB_PORT                GPIOB
-
-
+//#define Z80_O_ZCLK   SBIT(P_ZCLK, 5)
 #define        Z80_O_MREQ      SBIT(P_MREQ, 4)
 #define Z80_O_RD       SBIT(P_RD, 3)
 #define Z80_O_WR       SBIT(P_WR, 2)
 #define Z80_O_BUSREQ   SBIT(P_BUSREQ, 7)
 //#define Z80_O_NMI    SBIT(P_NMI, )
 #define Z80_O_RST      SBIT(P_RST, 5)
-#define Z80_I_BUSACK   SBIT(P_BUSACK, 6)
+#define Z80_I_BUSACK   SBIT(PIN_BUSACK, 6)
 //#define Z80_I_HALT   SBIT(P_HALT, )
 
-void z80_busreq(level_t level)
-{
-       Z80_O_BUSREQ = level;
-}
-
-void z80_reset(level_t level)
-{
-       Z80_O_RST = level;
-}
-
 
-void z80_reset_pulse(void)
-{
-       Z80_O_RST = 0;
-       _delay_us(10);
-       Z80_O_RST = 1;
-}
-
-#if 0
-int z80_stat_halt(void)
-{
-       return Z80_I_HALT;
-}
-#endif
+#define BUS_TO 20
 
 
 #define MASK(n)        ((1<<(n))-1)
 #define SMASK(w,s) (MASK(w) << (s))
 
 
-
 typedef union {
        uint32_t l;
        uint16_t w[2];
        uint8_t b[4];
 } addr_t;
 
-/*--------------------------------------------------------------------------*/
 
+static zstate_t zstate;
+static volatile uint8_t timer;         /* used for bus timeout */
 
+/*---------------------------------------------------------*/
+/* 10Hz timer interrupt generated by OC4A                  */
+/*---------------------------------------------------------*/
 
-/* 
- * A0..A6, A8..A13 are buffered. No need to disable.
- * A7, A14..A18: set to input.
- */
-static void z80_setup_adrbus_tristate(void)
+ISR(TIMER4_COMPA_vect)
 {
+
+       uint8_t i = timer;
+
+       if (i)
+               timer = i - 1;
+}
+
+/*--------------------------------------------------------------------------*/
+
+
+static void z80_addrbus_set_tristate(void)
+{
+       /* /MREQ, /RD, /WR: Input, no pullup */
+       DDR_MREQ &= ~(_BV(MREQ) | _BV(RD) | _BV(WR));
+       Z80_O_MREQ = 0;
+       Z80_O_RD = 0;
+       Z80_O_WR = 0;
+
        P_ADL = 0;
        DDR_ADL = 0;
        P_ADH = 0;
        DDR_ADH = 0;
-       PIN_ADB = P_ADB & MASK(ADB_WIDTH) << ADB_SHIFT;
+       PIN_ADB = P_ADB & (MASK(ADB_WIDTH) << ADB_SHIFT);
        DDR_ADB = DDR_ADB & ~(MASK(ADB_WIDTH) << ADB_SHIFT);
 }
 
-       
-static void z80_setup_adrbus_active(void)
+
+static void z80_addrbus_set_active(void)
 {
+       /* /MREQ, /RD, /WR: Output and high */
+       Z80_O_MREQ = 1;
+       Z80_O_RD = 1;
+       Z80_O_WR = 1;
+       DDR_MREQ |= _BV(MREQ) | _BV(RD) | _BV(WR);
+
        DDR_ADL = 0xff;
        DDR_ADH = 0xff;
        DDR_ADB = DDR_ADB | (MASK(ADB_WIDTH) << ADB_SHIFT);
 }
 
 
-
-static void z80_setup_dbus_in(void)
+static void z80_dbus_set_in(void)
 {
        DDR_DB = 0;
        P_DB = 0;
 }
 
-static void z80_setup_dbus_out(void)
+
+static void z80_dbus_set_out(void)
 {
        DDR_DB = 0xff;
 }
 
-static
-void z80_setaddress(uint32_t addr)
-{
-       addr_t x; x.l = addr;
 
-       P_ADL = x.b[0];
-       P_ADH = x.b[1];
-       PIN_ADB = ((x.b[2] << ADB_SHIFT) ^ P_ADB) & MASK(ADB_WIDTH) << ADB_SHIFT ;
+static void z80_reset_pulse(void)
+{
+       Z80_O_RST = 0;
+       _delay_us(10);
+       Z80_O_RST = 1;
 }
 
+
 void z80_setup_bus(void)
 {
+       /* /ZRESET: Output and low */
        Z80_O_RST = 0;
        DDR_RST |= _BV(RST);
 
+       /* /BUSREQ: Output and high */
        Z80_O_BUSREQ = 1;
        DDR_BUSREQ |= _BV(BUSREQ);
 
-//     Z80_O_NMI = 1;
-//     DDR_NMI |= _BV(NMI);
-
-       Z80_O_MREQ = 1;
-       Z80_O_RD = 1;
-       Z80_O_WR = 1;
-       DDR_MREQ |= _BV(MREQ) | _BV(RD) | _BV(WR);
-
+       /* /BUSACK: Input, no pullup */
        DDR_BUSACK &= ~_BV(BUSACK);
        P_BUSACK &= ~_BV(BUSACK);
 
+       /* /IOCS1: Input, no pullup */
        DDR_IOCS1 &= ~_BV(IOCS1);
        P_IOCS1 &= ~_BV(IOCS1);
 
-       //Z80_O_BUSREQ = 0;
-       //while(Z80_I_BUSACK == 1);
+       z80_addrbus_set_tristate();
+       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 */
 
-       z80_setup_adrbus_tristate();
-       z80_setup_dbus_in();
 }
 
-void z80_request_bus(void)
+
+zstate_t z80_bus_state(void)
 {
-       Z80_O_BUSREQ = 0;
-       while(Z80_I_BUSACK == 1);
-       z80_setup_adrbus_active();
+       return zstate;
 }
 
-void z80_release_bus(void)
+
+static void z80_busreq_hpulse(void)
 {
-       z80_setup_dbus_in();
-       z80_setup_adrbus_tristate();
-       Z80_O_BUSREQ = 1;
-       while(Z80_I_BUSACK == 0);
+       z80_dbus_set_in();
+       z80_addrbus_set_tristate();
+
+       ATOMIC_BLOCK(ATOMIC_FORCEON) {
+               Z80_O_BUSREQ = 1;
+               Z80_O_BUSREQ = 1;       /* 2 AVR clock cycles */
+               Z80_O_BUSREQ = 0;       /* 2 AVR clock cycles */
+       }
+
+       if (zstate & ZST_ACQUIRED) {
+               timer = BUS_TO;
+               while (Z80_I_BUSACK == 1 && timer)
+                       ;
+               if (Z80_I_BUSACK == 0)
+                       z80_addrbus_set_active();
+       }
+}
+
+
+/*
+
+ +              |               |               |               |               |
+    +   State   |     RESET     |  RESET_AQRD   |    RUNNING    | RUNNING_AQRD  |
+       +        |               |               |               |               |
+          +     |       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       |
+                |               |               |               |               |
+                |               |               |               |               |
+*/
+
+zstate_t z80_bus_cmd(bus_cmd_t cmd)
+{
+       switch (cmd) {
+
+       case Reset:
+               z80_dbus_set_in();
+               z80_addrbus_set_tristate();
+               Z80_O_RST = 0;
+               Z80_O_BUSREQ = 1;
+               zstate = RESET;
+               break;
+
+       case Request:
+               switch (zstate) {
+               case RESET:
+                       Z80_O_BUSREQ = 0;
+                       Z80_O_RST = 1;
+                       timer = BUS_TO;
+                       while (Z80_I_BUSACK == 1 && timer)
+                               ;
+                       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;
+                       timer = BUS_TO;
+                       while (Z80_I_BUSACK == 1 && timer)
+                               ;
+                       if (Z80_I_BUSACK == 0) {
+                               z80_addrbus_set_active();
+                               zstate = RUNNING_AQRD;
+                       } else {
+                               Z80_O_BUSREQ = 1;
+                       }
+                       break;
+
+               default:
+                       break;
+               }
+               break;
+
+       case Release:
+               switch (zstate) {
+               case RESET_AQRD:
+                       z80_dbus_set_in();
+                       z80_addrbus_set_tristate();
+                       Z80_O_RST = 0;
+                       Z80_O_BUSREQ = 1;
+                       zstate = RESET;
+                       break;
+               case RUNNING_AQRD:
+                       z80_dbus_set_in();
+                       z80_addrbus_set_tristate();
+                       Z80_O_BUSREQ = 1;
+                       zstate = RUNNING;
+                       break;
+               default:
+                       break;
+               }
+               break;
+
+       case Run:
+               switch (zstate) {
+               case RESET:
+                       Z80_O_RST = 1;
+                       zstate = RUNNING;
+                       break;
+
+               case RESET_AQRD:
+                       z80_dbus_set_in();
+                       z80_addrbus_set_tristate();
+                       z80_reset_pulse();
+                       z80_addrbus_set_active();
+                       zstate = RUNNING_AQRD;
+                       break;
+               default:
+                       break;
+               }
+               break;
+
+       case Restart:
+               switch (zstate) {
+               case RUNNING:
+               case RUNNING_AQRD:
+                       z80_reset_pulse();
+                       break;
+               default:
+                       break;
+               }
+               break;
+
+       case M_Cycle:
+               switch (zstate) {
+               case RUNNING_AQRD:
+                       z80_busreq_hpulse();    /* TODO: */
+                       break;
+               default:
+                       break;
+               }
+       }
+       return zstate;
+}
+
+
+/*--------------------------------------------------------------------------*/
+
+static
+//inline __attribute__ ((always_inline))
+void z80_setaddress(uint32_t addr)
+{
+       addr_t x; x.l = addr;
+
+       P_ADL = x.b[0];
+       P_ADH = x.b[1];
+       PIN_ADB = ((x.b[2] << ADB_SHIFT) ^ P_ADB) & MASK(ADB_WIDTH) << ADB_SHIFT ;
 }
 
 void z80_write(uint32_t addr, uint8_t data)
 {
        z80_setaddress(addr);
        Z80_O_MREQ = 0;
+       z80_dbus_set_out();
+       P_DB = data;
        P_DB = data;
-       z80_setup_dbus_out();
+       Z80_O_WR = 0;
        Z80_O_WR = 0;
        Z80_O_WR = 1;
        Z80_O_MREQ = 1;
@@ -318,7 +438,8 @@ uint8_t z80_read(uint32_t addr)
 
        z80_setaddress(addr);
        Z80_O_MREQ = 0;
-       z80_setup_dbus_in();
+       z80_dbus_set_in();
+       Z80_O_RD = 0;
        Z80_O_RD = 0;
        Z80_O_RD = 0;
        data = PIN_DB;
@@ -331,40 +452,80 @@ uint8_t z80_read(uint32_t addr)
 
 void z80_memset(uint32_t addr, uint8_t data, uint32_t length)
 {
-       z80_setup_dbus_out();
+       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;
+               Z80_O_WR = 0;
                Z80_O_WR = 1;
        }
        Z80_O_MREQ = 1;
 }
 
-void z80_write_block(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;
-       
-       z80_setup_dbus_out();
+
+       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;
                Z80_O_WR = 0;
                Z80_O_WR = 1;
        }
        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               ;
   017B'                         rx.out_idx:    ds      1               ;
   017C'                         rx.buf:                ds      rx.buf_len      ;
   018B'                         rx.buf_end     equ     $-1             ; last byte (start+len-1)
-                                
+
   018C'                         tx.bs_mask:    ds      1               ; (buf_len - 1)
   018D'                         tx.in_idx:     ds      1               ;
   018E'                         tx.out_idx:    ds      1               ;
@@ -393,22 +554,21 @@ static struct {
                idx_in,
                mask;
        } fifo_dsc[NUM_FIFOS];
-       
-
-void z80_memfifo_init(const fifo_t f, uint32_t adr)
-{
-
-DBG_P(2, "z80_memfifo_init: %i, %lx\n", f, adr);
 
-       fifo_dsc[f].base = adr;
 
-       z80_request_bus();
+void z80_memfifo_init(const fifo_t f, uint32_t addr)
+{
+       fifo_dsc[f].base = addr;
 
-       fifo_dsc[f].mask = z80_read(adr + FIFO_BUFSIZE_MASK);
-       fifo_dsc[f].idx_in = z80_read(adr + FIFO_INDEX_IN);
-       fifo_dsc[f].idx_out = z80_read(adr + FIFO_INDEX_OUT);
+DBG_P(2, "z80_memfifo_init: %i, %lx\n", f, addr);
 
-       z80_release_bus();
+       if (addr != 0) {
+               z80_bus_cmd(Request);
+               fifo_dsc[f].mask = z80_read(addr + FIFO_BUFSIZE_MASK);
+               fifo_dsc[f].idx_in = z80_read(addr + FIFO_INDEX_IN);
+               fifo_dsc[f].idx_out = z80_read(addr + FIFO_INDEX_OUT);
+               z80_bus_cmd(Release);
+       }
 }
 
 
@@ -421,9 +581,9 @@ int z80_memfifo_is_empty(const fifo_t f)
                uint32_t adr = fifo_dsc[f].base + FIFO_INDEX_IN;
                uint8_t idx;
 
-               z80_request_bus();
+               z80_bus_cmd(Request);
                idx = z80_read(adr);
-               z80_release_bus();
+               z80_bus_cmd(Release);
                rc = idx == fifo_dsc[f].idx_out;
        }
 
@@ -432,31 +592,50 @@ int z80_memfifo_is_empty(const fifo_t f)
 
 int z80_memfifo_is_full(const fifo_t f)
 {
-       int rc = 1;
-       
+       int rc = 0;
+
        if (fifo_dsc[f].base != 0) {
-               z80_request_bus();
+               z80_bus_cmd(Request);
                rc = ((fifo_dsc[f].idx_in + 1) & fifo_dsc[f].mask)
                        == z80_read(fifo_dsc[f].base+FIFO_INDEX_OUT);
-               z80_release_bus();
+               z80_bus_cmd(Release);
        }
        return rc;
 }
 
-uint8_t z80_memfifo_getc(const fifo_t f)
+
+uint8_t z80_memfifo_getc_wait(const fifo_t f)
 {
        uint8_t rc, idx;
-       
+
        while (z80_memfifo_is_empty(f))
                ;
 
-       z80_request_bus();
+       z80_bus_cmd(Request);
        idx = fifo_dsc[f].idx_out;
        rc = z80_read(fifo_dsc[f].base+idx);
        fifo_dsc[f].idx_out = ++idx & fifo_dsc[f].mask;
        z80_write(fifo_dsc[f].base+FIFO_INDEX_OUT, fifo_dsc[f].idx_out);
-       z80_release_bus();
-       
+       z80_bus_cmd(Release);
+
+       return rc;
+}
+
+int z80_memfifo_getc(const fifo_t f)
+{
+       int rc = -1;
+
+       if (fifo_dsc[f].base != 0) {
+               uint8_t idx = fifo_dsc[f].idx_out;
+               z80_bus_cmd(Request);
+               if (idx != z80_read(fifo_dsc[f].base + FIFO_INDEX_IN)) {
+                       rc = z80_read(fifo_dsc[f].base+idx);
+                       fifo_dsc[f].idx_out = ++idx & fifo_dsc[f].mask;
+                       z80_write(fifo_dsc[f].base+FIFO_INDEX_OUT, fifo_dsc[f].idx_out);
+               }
+               z80_bus_cmd(Release);
+       }
+
        return rc;
 }
 
@@ -464,100 +643,14 @@ uint8_t z80_memfifo_getc(const fifo_t f)
 void z80_memfifo_putc(fifo_t f, uint8_t val)
 {
        int idx;
-       
+
        while (z80_memfifo_is_full(f))
                ;
 
-       z80_request_bus();
+       z80_bus_cmd(Request);
        idx = fifo_dsc[f].idx_in;
        z80_write(fifo_dsc[f].base+idx, val);
        fifo_dsc[f].idx_in = ++idx & fifo_dsc[f].mask;
        z80_write(fifo_dsc[f].base+FIFO_INDEX_IN, fifo_dsc[f].idx_in);
-       z80_release_bus();
-}
-
-/*--------------------------------------------------------------------------*/
-
-static struct {
-       uint32_t base;
-       //uint8_t  idx_out, idx_in;
-       uint16_t count;
-       uint8_t  buf[256];
-       } msg_fifo;
-
-/*--------------------------------------------------------------------------*/
-
-#if 0
-
-static void tim1_setup(void)
-{
-       RCC_APB2RSTR |= RCC_APB2RSTR_TIM1RST;
-       RCC_APB2RSTR &= ~RCC_APB2RSTR_TIM1RST;
-
-       TIM1_CR1 = 0;
-
-       TIM1_SMCR = 0
-       /*      | TIM_SMCR_ETP                  */
-       /*      | TIM_SMCR_ETF_CK_INT_N_2       */
-               | TIM_SMCR_TS_ETRF
-               | TIM_SMCR_SMS_OFF
-               ;
-
-       TIM1_DIER = TIM_DIER_TDE;
-
-
-       TIM1_CCMR1 = 0
-               | TIM_CCMR1_OC1M_FORCE_LOW
-               | TIM_CCMR1_CC1S_OUT;
-
-       TIM1_SMCR |= TIM_SMCR_SMS_TM;
-}
-
-#endif
-
-/*--------------------------------------------------------------------------*/
-
-void z80_setup_msg_fifo(void)
-{
-//     gpio_set_mode(P_BUSACK, GPIO_MODE_INPUT,
-//             GPIO_CNF_INPUT_FLOAT, GPIO_BUSACK | GPIO_IOCS1);
-
-//...
-
-//     msg_fifo.count = NELEMS(msg_fifo.buf);
-       msg_fifo.count = 0;
-       msg_fifo.base = 0;
-
-}
-
-
-void z80_init_msg_fifo(uint32_t addr)
-{
-
-DBG_P(1, "z80_init_msg_fifo: %lx\n", addr);
-
-       z80_request_bus();
-       z80_write(addr+FIFO_INDEX_OUT, z80_read(addr+FIFO_INDEX_IN));
-       z80_release_bus();
-       msg_fifo.base = addr;
-}
-
-
-int z80_msg_fifo_getc(void)
-{
-       int c = -1;
-       
-       if (msg_fifo.count != (NELEMS(msg_fifo.buf) /*- DMA1_CNDTR4 */ )) {
-               c = msg_fifo.buf[msg_fifo.count];
-               if (++msg_fifo.count == NELEMS(msg_fifo.buf))
-                       msg_fifo.count = 0;
-
-               if (msg_fifo.base != 0) {
-                       z80_request_bus();
-                       z80_write(msg_fifo.base+FIFO_INDEX_OUT, msg_fifo.count);
-                       z80_release_bus();
-               }
-       }
-
-       return c;
+       z80_bus_cmd(Release);
 }