Merge pull request #24 from Z80-Retro/dev

Refactor BIOS and I/O lib for shared use on both the Retro! and Nouveau

.gitignore

@@ -4,3 +4,4 @@
 *.sym
 mkfs
 2063-Z80-cpm.zip
+Make.local

filesystem/Make.default → Make.default

@@ -1,3 +1,6 @@
+# DO NOT EDIT THIS FILE
+# Override these values if needed by assigning different values in a Make.local file
+
 # A set of default values of things that might be of 
 # interest to more than one Makefile.
 
@@ -8,3 +11,10 @@ SD_DEV=/dev/sda1
 
 # This is used before burning an SD card image to make sure we are on the correct host!
 SD_HOSTNAME=raspberrypi
+
+# Be default, build for the Z80-Retro!
+ASM_FLAGS=-I../lib -I../libretro
+
+BOOT_MSG=Z80 Retro Board 2063.3
+
+-include $(TOP)/Make.local

Makefile

@@ -1,8 +1,8 @@
 SUBDIRS=\
 	boot \
+	retro \
 	tests \
 	hello \
-	retro \
 	filesystem
 
 CLEAN_DIRS=$(SUBDIRS:%=clean-%)
@@ -33,6 +33,8 @@ REL_FILES=\
 	doc \
 	hello \
 	lib \
+	libretro \
+	libnouveau \
 	retro \
 	tests \
 	filesystem/Makefile \

README-SD.md

@@ -47,7 +47,7 @@ Do *NOT* expect that you will be able to recover any data after doing this!
 On my raspberry PI, with only one SD adapter plugged into a USB port, I use the 
 following command:
 
-	sudo dd if=/dev/zero of=/dev/sda bs=512 count=10
+	sudo dd if=/dev/zero of=/dev/sda bs=512 count=100 conv=fsync
 
 ## Partition your SD card
 
@@ -120,7 +120,7 @@ At this point, Liunux should recognize that the drive has one partition on it:
 
 If we write "Hello world!" into partition 1:
 
-	echo "Hello world!" | sudo dd of=/dev/sda1 bs=512
+	echo "Hello world!" | sudo dd of=/dev/sda1 bs=512 conv=fsync
 
 ...then we can see it by looking at the raw disk image:
 

boot/Makefile

@@ -1,4 +1,6 @@
-ASM_FLAGS=-I../lib
+
+TOP=..
+include $(TOP)/Make.default
 
 
 all: firmware.bin
@@ -7,10 +9,10 @@ clean:
 	rm -f ldr
 	rm -f *.lst *.bin *.hex *.sym
 
-DATE := $(shell date --rfc-3339=seconds)
+DATE := $(shell date +"%Y-%m-%d %H:%M:%S%z")
 GIT_VERSION := $(shell git describe --long --dirty; git show -s --format='%ci')
 %.bin: %.asm
-	cat $< | sed -e "s/@@DATE@@/$(DATE)/g" -e "s/@@GIT_VERSION@@/$(GIT_VERSION)/g" | z80asm - -o $@ --list=$(basename $@).lst --label=$(basename $@).sym $(ASM_FLAGS)
+	cat $< | sed -e "s/@@DATE@@/$(DATE)/g" -e "s/@@GIT_VERSION@@/$(GIT_VERSION)/g" -e "s/@@BOOT_MSG@@/$(BOOT_MSG)/g" | z80asm - -o $@ --list=$(basename $@).lst --label=$(basename $@).sym $(ASM_FLAGS)
 
 
 world: clean all

boot/firmware.asm

@@ -1,6 +1,6 @@
 ;****************************************************************************
 ;
-;    Copyright (C) 2021,2022,2023 John Winans
+;    Copyright (C) 2021,2022,2023,2024 John Winans
 ;
 ;    This library is free software; you can redistribute it and/or
 ;    modify it under the terms of the GNU Lesser General Public
@@ -53,7 +53,7 @@ include	'memory.asm'
 	; NOTE THAT THE SRAM IS NOT READABLE AT THIS POINT
 	;###################################################
 
-	; Select SRAM low bank 14, idle the SD card, and idle printer signals
+	; Select SRAM low bank, idle the SD card, etc.
 	ld	a,(gpio_out_cache)
 	out	(gpio_out),a
 
@@ -73,14 +73,8 @@ include	'memory.asm'
 
 	ld	sp,.stacktop
 
-	; Initialize the CTC so that the SIO will have a baud clock if J11-A is set to the CTC!
-	;ld	c,1			; 115200 bps
-	;ld	c,6			; 19200 bps
-	ld	c,12			; 9600 bps
-	call	init_ctc_1
-
-	; Init the SIO to run at 115200 or at the CTC rate depending on J11-A
-	call	sioa_init
+        call    bsp_init                ; board-specific init
+        call    con_init
 
 	; Display a hello world message.
 	ld	hl,.boot_msg
@@ -100,7 +94,7 @@ include	'memory.asm'
 .boot_msg:
 	db	'\r\n\n'
 	db	'##############################################################################\r\n'
-	db	'Z80 Retro Board 2063.3\r\n'
+	db	'@@BOOT_MSG@@\r\n'
 	db	'      git: @@GIT_VERSION@@\r\n'
 	db	'    build: @@DATE@@\r\n'
 	db	'\0'
@@ -446,17 +440,15 @@ endif
 include	'sdcard.asm'
 include	'spi.asm'
 include	'hexdump.asm'
-include 'sio.asm'
-include 'ctc1.asm'
+include 'console.asm'
 include 'puts.asm'
+include 'bsp.asm'
 
 ;##############################################################################
 ; This is a cache of the last written data to the gpio_out port.
 ; The initial value here is what is written to the latch during startup.
 ;##############################################################################
-.low_bank:      equ     0x0e    ; The RAM BANK to use for the bottom 32K
-gpio_out_cache:	db	gpio_out_sd_mosi|gpio_out_sd_ssel|gpio_out_prn_stb|gpio_out_sd_clk|(.low_bank<<4)
-
+gpio_out_cache:	db	gpio_out_init
 
 ;##############################################################################
 ; This marks the end of the data copied from FLASH into RAM during boot

filesystem/Makefile

@@ -22,9 +22,11 @@
 
 all::
 
-# optionally include rules from a local file:
-include Make.default
--include Make.local
+
+# Include the detault and any local override rules
+# Must set TOP before including Make.default
+TOP=..
+include $(TOP)/Make.default
 
 .PHONY: all clean world burn blank-all-sd
 

hello/Makefile

@@ -1,13 +1,14 @@
-ASM_FLAGS=-I../lib
 
+TOP=..
+include $(TOP)/Make.default
 
 all: hello.bin
 
 clean:
 	rm -f ldr
 	rm -f *.lst *.bin *.hex
 
-DATE := $(shell date --rfc-3339=seconds)
+DATE := $(shell date +"%Y-%m-%d %H:%M:%S%z")
 GIT_VERSION := $(shell git describe --long --dirty; git show -s --format='%ci')
 %.bin: %.asm
 	cat $< | sed -e "s/@@DATE@@/$(DATE)/g" -e "s/@@GIT_VERSION@@/$(GIT_VERSION)/g" | z80asm - -o $@ --list=$(basename $@).lst $(ASM_FLAGS)

hello/hello.asm

@@ -54,6 +54,5 @@ include	'memory.asm'
 
 
 include	'hexdump.asm'
-include 'sio.asm'
-include 'ctc1.asm'
+include 'console.asm'
 include 'puts.asm'

libnouveau/bsp.asm

@@ -0,0 +1,35 @@
+;****************************************************************************
+;
+;    Copyright (C) 2024 John Winans
+;
+;    This library is free software; you can redistribute it and/or
+;    modify it under the terms of the GNU Lesser General Public
+;    License as published by the Free Software Foundation; either
+;    version 2.1 of the License, or (at your option) any later version.
+;
+;    This library is distributed in the hope that it will be useful,
+;    but WITHOUT ANY WARRANTY; without even the implied warranty of
+;    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+;    Lesser General Public License for more details.
+;
+;    You should have received a copy of the GNU Lesser General Public
+;    License along with this library; if not, write to the Free Software
+;    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
+;    USA
+;
+; https://github.com/johnwinans/2063-Z80-cpm
+;
+;****************************************************************************
+
+bsp_init:
+        ld      a,0
+        ;out0     (0x36),a        ; RCR = 0 = disable the DRAM refresh controller
+        db      0xed,0x39,0x36
+        ;out0     (0x32),a        ; DCNTL = 0 = zero wait states
+        db      0xed,0x39,0x32
+
+        ld      a,0x80
+        ;out0    (0x1f),a        ; CCR = 0x80 = run at 1X extal clock speed
+        db      0xed,0x39,0x1f
+
+        ret

libnouveau/console.asm

@@ -0,0 +1,117 @@
+;****************************************************************************
+;
+;	 Copyright (C) 2024 John Winans
+;
+;	 This library is free software; you can redistribute it and/or
+;	 modify it under the terms of the GNU Lesser General Public
+;	 License as published by the Free Software Foundation; either
+;	 version 2.1 of the License, or (at your option) any later version.
+;
+;	 This library is distributed in the hope that it will be useful,
+;	 but WITHOUT ANY WARRANTY; without even the implied warranty of
+;	 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+;	 Lesser General Public License for more details.
+;
+;	 You should have received a copy of the GNU Lesser General Public
+;	 License along with this library; if not, write to the Free Software
+;	 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
+;	 USA
+;
+; https://github.com/johnwinans/2063-Z80-cpm
+;
+;****************************************************************************
+
+; Drivers for the Z8S180 ASCI 
+
+.CNTLA0: equ     0x00
+.CNTLB0: equ     0x02
+.RDR0:   equ     0x08
+.ASEXT0: equ     0x12
+.STAT0:  equ     0x04
+.TDR0:   equ     0x06
+
+;##############################################################
+; Return NZ if the console UART is ready and Z (with A=0) if not ready.
+; Clobbers: AF
+;##############################################################
+con_tx_ready:
+        ;IN0     A,(.STAT0)      ;C4H,read status
+        db      11101101B,00111000B,.STAT0
+        AND     2
+	ret			; a = 0 = not ready
+
+;##############################################################
+; Return NZ if the console UART is ready and Z (with A=0) if not ready.
+; Clobbers: AF
+;##############################################################
+con_rx_ready:
+        ; hack to clear any overrun errors (See Errata about ASCI seizures)
+        ;IN0     A,(.CNTLA0)      ;C4H,read status
+        db      11101101B,00111000B,.CNTLA0
+        and     ~0x08
+        ;OUT0    (.CNTLA0),A
+        db      0xed,0x39,.CNTLA0
+
+        ;IN0     A,(.STAT0)      ;C4H,read status
+        db      11101101B,00111000B,.STAT0
+        AND     10000000B
+	ret			; 0 = not ready
+
+
+;##############################################################
+; stolen from https://groups.google.com/g/retro-comp/c/N574sGiwmaI?pli=1
+; mods are my fault :-)
+;##############################################################
+con_init:
+        LD      A,01100100B    ; rcv enable, xmit enable, no parity
+        ;LD      A,01100101B    ; rcv enable, xmit enable, no parity
+        ;OUT0    (.CNTLA0),A    ; set cntla
+        db      0xed,0x39,.CNTLA0
+
+        LD      A,00000000B    ; div 10, div 16, div 2 18432000/1/1/10/16/1 = 115200
+        ;OUT0    (.CNTLB0),A     ; set cntlb
+        db      0xed,0x39,.CNTLB0
+
+        LD      A,01100110B    ; no cts, no dcd, no break detect
+        ;OUT0    (.ASEXT0),A     ; set ASCI0 EXTENSION CONTROL (Z8S180 only)
+        db      0xed,0x39,.ASEXT0
+        XOR     A
+        ;OUT0    (.STAT0),A      ; ASCI Status Reg Ch 0
+        db      0xed,0x39,.STAT0
+        ret
+
+
+;##############################################################
+; Wait for the transmitter to become ready and then
+; print the character in the C register.
+; Clobbers: AF
+;##############################################################
+con_tx_char:
+	call	con_tx_ready
+	jr	z,con_tx_char
+	ld	a,c
+
+        ;OUT0    (.TDR0),A       ;C6H
+        db      0xed,0x39,.TDR0
+
+	ret
+
+;##############################################################
+; Wait for the receiver to become ready and then return the 
+; character in the A register.
+; Clobbers: AF
+;
+; XXX need to concern ourselves with the Errata note that
+; says we need to write zero into CNTLA0, bit 3 (ERF) to
+; reset an overflow error flag when set because RX will
+; seize.
+;
+;##############################################################
+con_rx_char:
+	call	con_rx_ready
+	jr	z,con_rx_char
+
+        ;IN0     A,(.RDR0)
+        db      11101101B,00111000B,.RDR0
+
+	ret

libnouveau/io.asm

@@ -0,0 +1,42 @@
+;****************************************************************************
+;
+;    Copyright (C) 2024 John Winans
+;
+;    This library is free software; you can redistribute it and/or
+;    modify it under the terms of the GNU Lesser General Public
+;    License as published by the Free Software Foundation; either
+;    version 2.1 of the License, or (at your option) any later version.
+;
+;    This library is distributed in the hope that it will be useful,
+;    but WITHOUT ANY WARRANTY; without even the implied warranty of
+;    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+;    Lesser General Public License for more details.
+;
+;    You should have received a copy of the GNU Lesser General Public
+;    License along with this library; if not, write to the Free Software
+;    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
+;    USA
+;
+; https://github.com/johnwinans/2063-Z80-cpm
+;
+;****************************************************************************
+
+; Z80 Nouveau
+
+gpio_in:		equ     0xf0		; GP input port
+gpio_out:		equ	0xf1		; GP output port
+flash_disable:		equ	0xfe		; dummy-read from this port to disable the FLASH
+
+; bit-assignments for General Purpose output port 
+gpio_out_sd_mosi:	equ	0x01
+gpio_out_sd_clk:	equ	0x02
+gpio_out_sd_ssel:	equ	0x04
+
+; bit-assignments for General Purpose input port 
+;gpio_in_user1:		equ	0x20 
+gpio_in_sd_det:		equ	0x40
+gpio_in_sd_miso:	equ	0x80
+
+; The initial value to write into the gpio_out latch.
+; The value here will idle the SD card interface.
+gpio_out_init:          equ     gpio_out_sd_mosi|gpio_out_sd_clk|gpio_out_sd_ssel