From dc94445695465a22fe7bc2809d622dd6f3672968 Mon Sep 17 00:00:00 2001 From: Mika Tuupola Date: Sun, 16 Oct 2011 21:35:16 +0300 Subject: [PATCH] Code for reading 74HC165 values. --- 74hc165_piso/Makefile | 501 ++++++++++++++++++++++++++++++++++++++ 74hc165_piso/main.c | 141 +++++++++++ 74hc165_piso/main.h | 2 + 74hc165_piso/timer.c | 63 +++++ 74hc165_piso/timer.h | 25 ++ 74hc165_piso/uart.h | 12 + 74hc165_piso/uart_async.c | 102 ++++++++ 7 files changed, 846 insertions(+) create mode 100644 74hc165_piso/Makefile create mode 100644 74hc165_piso/main.c create mode 100644 74hc165_piso/main.h create mode 100644 74hc165_piso/timer.c create mode 100644 74hc165_piso/timer.h create mode 100644 74hc165_piso/uart.h create mode 100644 74hc165_piso/uart_async.c diff --git a/74hc165_piso/Makefile b/74hc165_piso/Makefile new file mode 100644 index 0000000..cba8518 --- /dev/null +++ b/74hc165_piso/Makefile @@ -0,0 +1,501 @@ +# ---------------------------------------------------------------------------- +# Makefile based on WinAVR Makefile Template written by Eric B. Weddington, +# Jörg Wunsch, et al. +# +# Adjust F_CPU below to the clock frequency in Mhz of your AVR target +# +# Adjust the size of the uart receive and transmit ringbuffer in bytes using +# defines -DUART_RX_BUFFER_SIZE=128 and -DUART_TX_BUFFER_SIZE=128 in the +# CDEF section below +# +#---------------------------------------------------------------------------- +# On command line: +# +# make all = Make software. +# +# make clean = Clean out built project files. +# +# make coff = Convert ELF to AVR COFF. +# +# make extcoff = Convert ELF to AVR Extended COFF. +# +# make program = Download the hex file to the device, using avrdude. +# Please customize the avrdude settings below first! +# +# make debug = Start either simulavr or avarice as specified for debugging, +# with avr-gdb or avr-insight as the front end for debugging. +# +# make filename.s = Just compile filename.c into the assembler code only. +# +# make filename.i = Create a preprocessed source file for use in submitting +# bug reports to the GCC project. +# +# To rebuild project do "make clean" then "make all". +#---------------------------------------------------------------------------- + + +# MCU name +MCU = atmega328p + +# Processor frequency. +# This will define a symbol, F_CPU, in all source code files equal to the +# processor frequency. You can then use this symbol in your source code to +# calculate timings. Do NOT tack on a 'UL' at the end, this will be done +# automatically to create a 32-bit value in your source code. +F_CPU = 16000000 + +# Output format. (can be srec, ihex, binary) +FORMAT = ihex + +# Target file name (without extension). +TARGET = main + +# List C source files here. (C dependencies are automatically generated.) +SRC = $(TARGET).c uart_async.c timer.c + +# List Assembler source files here. +# Make them always end in a capital .S. Files ending in a lowercase .s +# will not be considered source files but generated files (assembler +# output from the compiler), and will be deleted upon "make clean"! +# Even though the DOS/Win* filesystem matches both .s and .S the same, +# it will preserve the spelling of the filenames, and gcc itself does +# care about how the name is spelled on its command-line. +ASRC = + + +# Optimization level, can be [0, 1, 2, 3, s]. +# 0 = turn off optimization. s = optimize for size. +# (Note: 3 is not always the best optimization level. See avr-libc FAQ.) +OPT = s + + +# Debugging format. +# Native formats for AVR-GCC's -g are dwarf-2 [default] or stabs. +# AVR Studio 4.10 requires dwarf-2. +# AVR [Extended] COFF format requires stabs, plus an avr-objcopy run. +DEBUG = dwarf-2 + + +# List any extra directories to look for include files here. +# Each directory must be seperated by a space. +# Use forward slashes for directory separators. +# For a directory that has spaces, enclose it in quotes. +EXTRAINCDIRS = + + +# Compiler flag to set the C Standard level. +# c89 = "ANSI" C +# gnu89 = c89 plus GCC extensions +# c99 = ISO C99 standard (not yet fully implemented) +# gnu99 = c99 plus GCC extensions +CSTANDARD = -std=gnu99 + + +# Place -D or -U options here +CDEFS = -DF_CPU=$(F_CPU)UL + +# uncomment and adapt these line if you want different UART library buffer size +#CDEFS += -DUART_RX_BUFFER_SIZE=128 +#CDEFS += -DUART_TX_BUFFER_SIZE=128 + + +# Place -I options here +CINCS = + + + +#---------------- Compiler Options ---------------- +# -g*: generate debugging information +# -O*: optimization level +# -f...: tuning, see GCC manual and avr-libc documentation +# -Wall...: warning level +# -Wa,...: tell GCC to pass this to the assembler. +# -adhlns...: create assembler listing +CFLAGS = -g$(DEBUG) +CFLAGS += $(CDEFS) $(CINCS) +CFLAGS += -O$(OPT) +CFLAGS += -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums +CFLAGS += -Wall -Wstrict-prototypes +CFLAGS += -Wa,-adhlns=$(<:.c=.lst) +CFLAGS += $(patsubst %,-I%,$(EXTRAINCDIRS)) +CFLAGS += $(CSTANDARD) + + +#---------------- Assembler Options ---------------- +# -Wa,...: tell GCC to pass this to the assembler. +# -ahlms: create listing +# -gstabs: have the assembler create line number information; note that +# for use in COFF files, additional information about filenames +# and function names needs to be present in the assembler source +# files -- see avr-libc docs [FIXME: not yet described there] +ASFLAGS = -Wa,-adhlns=$(<:.S=.lst),-gstabs + + +#---------------- Library Options ---------------- +# Minimalistic printf version +PRINTF_LIB_MIN = -Wl,-u,vfprintf -lprintf_min + +# Floating point printf version (requires MATH_LIB = -lm below) +PRINTF_LIB_FLOAT = -Wl,-u,vfprintf -lprintf_flt + +# If this is left blank, then it will use the Standard printf version. +PRINTF_LIB = +#PRINTF_LIB = $(PRINTF_LIB_MIN) +#PRINTF_LIB = $(PRINTF_LIB_FLOAT) + + +# Minimalistic scanf version +SCANF_LIB_MIN = -Wl,-u,vfscanf -lscanf_min + +# Floating point + %[ scanf version (requires MATH_LIB = -lm below) +SCANF_LIB_FLOAT = -Wl,-u,vfscanf -lscanf_flt + +# If this is left blank, then it will use the Standard scanf version. +SCANF_LIB = +#SCANF_LIB = $(SCANF_LIB_MIN) +#SCANF_LIB = $(SCANF_LIB_FLOAT) + + +MATH_LIB = -lm + + + +#---------------- External Memory Options ---------------- + +# 64 KB of external RAM, starting after internal RAM (ATmega128!), +# used for variables (.data/.bss) and heap (malloc()). +#EXTMEMOPTS = -Wl,-Tdata=0x801100,--defsym=__heap_end=0x80ffff + +# 64 KB of external RAM, starting after internal RAM (ATmega128!), +# only used for heap (malloc()). +#EXTMEMOPTS = -Wl,--defsym=__heap_start=0x801100,--defsym=__heap_end=0x80ffff + +EXTMEMOPTS = + + + +#---------------- Linker Options ---------------- +# -Wl,...: tell GCC to pass this to linker. +# -Map: create map file +# --cref: add cross reference to map file +LDFLAGS = -Wl,-Map=$(TARGET).map,--cref +LDFLAGS += $(EXTMEMOPTS) +LDFLAGS += $(PRINTF_LIB) $(SCANF_LIB) $(MATH_LIB) + + + +#---------------- Programming Options (avrdude) ---------------- + +# Programming hardware: alf avr910 avrisp bascom bsd +# dt006 pavr picoweb pony-stk200 sp12 stk200 stk500 +# +# Type: avrdude -c ? +# to get a full listing. +# +AVRDUDE_PROGRAMMER = arduino + +# com1 = serial port. Use lpt1 to connect to parallel port. +AVRDUDE_PORT = /dev/tty.usb* # programmer connected to serial device + +AVRDUDE_WRITE_FLASH = -U flash:w:$(TARGET).hex +#AVRDUDE_WRITE_EEPROM = -U eeprom:w:$(TARGET).eep + + +# Uncomment the following if you want avrdude's erase cycle counter. +# Note that this counter needs to be initialized first using -Yn, +# see avrdude manual. +#AVRDUDE_ERASE_COUNTER = -y + +# Uncomment the following if you do /not/ wish a verification to be +# performed after programming the device. +#AVRDUDE_NO_VERIFY = -V + +# Increase verbosity level. Please use this when submitting bug +# reports about avrdude. See +# to submit bug reports. +#AVRDUDE_VERBOSE = -v -v + +AVRDUDE_FLAGS = -p $(MCU) -P $(AVRDUDE_PORT) -c $(AVRDUDE_PROGRAMMER) -b 57600 +AVRDUDE_FLAGS += $(AVRDUDE_NO_VERIFY) +AVRDUDE_FLAGS += $(AVRDUDE_VERBOSE) +AVRDUDE_FLAGS += $(AVRDUDE_ERASE_COUNTER) + + + +#---------------- Debugging Options ---------------- + +# For simulavr only - target MCU frequency. +DEBUG_MFREQ = $(F_CPU) + +# Set the DEBUG_UI to either gdb or insight. +# DEBUG_UI = gdb +DEBUG_UI = insight + +# Set the debugging back-end to either avarice, simulavr. +DEBUG_BACKEND = avarice +#DEBUG_BACKEND = simulavr + +# GDB Init Filename. +GDBINIT_FILE = __avr_gdbinit + +# When using avarice settings for the JTAG +JTAG_DEV = /dev/com1 + +# Debugging port used to communicate between GDB / avarice / simulavr. +DEBUG_PORT = 4242 + +# Debugging host used to communicate between GDB / avarice / simulavr, normally +# just set to localhost unless doing some sort of crazy debugging when +# avarice is running on a different computer. +DEBUG_HOST = localhost + + + +#============================================================================ + + +# Define programs and commands. +SHELL = sh +CC = avr-gcc +OBJCOPY = avr-objcopy +OBJDUMP = avr-objdump +SIZE = avr-size +NM = avr-nm +AVRDUDE = avrdude +REMOVE = rm -f +COPY = cp +WINSHELL = cmd + + +# Define Messages +# English +MSG_ERRORS_NONE = Errors: none +MSG_BEGIN = -------- begin -------- +MSG_END = -------- end -------- +MSG_SIZE_BEFORE = Size before: +MSG_SIZE_AFTER = Size after: +MSG_COFF = Converting to AVR COFF: +MSG_EXTENDED_COFF = Converting to AVR Extended COFF: +MSG_FLASH = Creating load file for Flash: +MSG_EEPROM = Creating load file for EEPROM: +MSG_EXTENDED_LISTING = Creating Extended Listing: +MSG_SYMBOL_TABLE = Creating Symbol Table: +MSG_LINKING = Linking: +MSG_COMPILING = Compiling: +MSG_ASSEMBLING = Assembling: +MSG_CLEANING = Cleaning project: + + + + +# Define all object files. +OBJ = $(SRC:.c=.o) $(ASRC:.S=.o) + +# Define all listing files. +LST = $(SRC:.c=.lst) $(ASRC:.S=.lst) + + +# Compiler flags to generate dependency files. +GENDEPFLAGS = -MD -MP -MF .dep/$(@F).d + + +# Combine all necessary flags and optional flags. +# Add target processor to flags. +ALL_CFLAGS = -mmcu=$(MCU) -I. $(CFLAGS) $(GENDEPFLAGS) +ALL_ASFLAGS = -mmcu=$(MCU) -I. -x assembler-with-cpp $(ASFLAGS) + + + + + +# Default target. +all: begin gccversion sizebefore build sizeafter end + +build: elf hex eep lss sym + +elf: $(TARGET).elf +hex: $(TARGET).hex +eep: $(TARGET).eep +lss: $(TARGET).lss +sym: $(TARGET).sym + + + +# Eye candy. +# AVR Studio 3.x does not check make's exit code but relies on +# the following magic strings to be generated by the compile job. +begin: + @echo + @echo $(MSG_BEGIN) + +end: + @echo $(MSG_END) + @echo + + +# Display size of file. +HEXSIZE = $(SIZE) --target=$(FORMAT) $(TARGET).hex +ELFSIZE = $(SIZE) -A $(TARGET).elf +AVRMEM = avr-mem.sh $(TARGET).elf $(MCU) + +sizebefore: + @if test -f $(TARGET).elf; then echo; echo $(MSG_SIZE_BEFORE); $(ELFSIZE); \ + $(AVRMEM) 2>/dev/null; echo; fi + +sizeafter: + @if test -f $(TARGET).elf; then echo; echo $(MSG_SIZE_AFTER); $(ELFSIZE); \ + $(AVRMEM) 2>/dev/null; echo; fi + + + +# Display compiler version information. +gccversion : + @$(CC) --version + + + +# Program the device. +program: $(TARGET).hex $(TARGET).eep + $(AVRDUDE) $(AVRDUDE_FLAGS) $(AVRDUDE_WRITE_FLASH) $(AVRDUDE_WRITE_EEPROM) + + +# Generate avr-gdb config/init file which does the following: +# define the reset signal, load the target file, connect to target, and set +# a breakpoint at main(). +gdb-config: + @$(REMOVE) $(GDBINIT_FILE) + @echo define reset >> $(GDBINIT_FILE) + @echo SIGNAL SIGHUP >> $(GDBINIT_FILE) + @echo end >> $(GDBINIT_FILE) + @echo file $(TARGET).elf >> $(GDBINIT_FILE) + @echo target remote $(DEBUG_HOST):$(DEBUG_PORT) >> $(GDBINIT_FILE) +ifeq ($(DEBUG_BACKEND),simulavr) + @echo load >> $(GDBINIT_FILE) +endif + @echo break main >> $(GDBINIT_FILE) + +debug: gdb-config $(TARGET).elf +ifeq ($(DEBUG_BACKEND), avarice) + @echo Starting AVaRICE - Press enter when "waiting to connect" message displays. + @$(WINSHELL) /c start avarice --jtag $(JTAG_DEV) --erase --program --file \ + $(TARGET).elf $(DEBUG_HOST):$(DEBUG_PORT) + @$(WINSHELL) /c pause + +else + @$(WINSHELL) /c start simulavr --gdbserver --device $(MCU) --clock-freq \ + $(DEBUG_MFREQ) --port $(DEBUG_PORT) +endif + @$(WINSHELL) /c start avr-$(DEBUG_UI) --command=$(GDBINIT_FILE) + + + + +# Convert ELF to COFF for use in debugging / simulating in AVR Studio or VMLAB. +COFFCONVERT=$(OBJCOPY) --debugging \ +--change-section-address .data-0x800000 \ +--change-section-address .bss-0x800000 \ +--change-section-address .noinit-0x800000 \ +--change-section-address .eeprom-0x810000 + + +coff: $(TARGET).elf + @echo + @echo $(MSG_COFF) $(TARGET).cof + $(COFFCONVERT) -O coff-avr $< $(TARGET).cof + + +extcoff: $(TARGET).elf + @echo + @echo $(MSG_EXTENDED_COFF) $(TARGET).cof + $(COFFCONVERT) -O coff-ext-avr $< $(TARGET).cof + + + +# Create final output files (.hex, .eep) from ELF output file. +%.hex: %.elf + @echo + @echo $(MSG_FLASH) $@ + $(OBJCOPY) -O $(FORMAT) -R .eeprom $< $@ + +%.eep: %.elf + @echo + @echo $(MSG_EEPROM) $@ + -$(OBJCOPY) -j .eeprom --set-section-flags=.eeprom="alloc,load" \ + --change-section-lma .eeprom=0 -O $(FORMAT) $< $@ + +# Create extended listing file from ELF output file. +%.lss: %.elf + @echo + @echo $(MSG_EXTENDED_LISTING) $@ + $(OBJDUMP) -h -S $< > $@ + +# Create a symbol table from ELF output file. +%.sym: %.elf + @echo + @echo $(MSG_SYMBOL_TABLE) $@ + $(NM) -n $< > $@ + + + +# Link: create ELF output file from object files. +.SECONDARY : $(TARGET).elf +.PRECIOUS : $(OBJ) +%.elf: $(OBJ) + @echo + @echo $(MSG_LINKING) $@ + $(CC) $(ALL_CFLAGS) $^ --output $@ $(LDFLAGS) + + +# Compile: create object files from C source files. +%.o : %.c + @echo + @echo $(MSG_COMPILING) $< + $(CC) -c $(ALL_CFLAGS) $< -o $@ + + +# Compile: create assembler files from C source files. +%.s : %.c + $(CC) -S $(ALL_CFLAGS) $< -o $@ + + +# Assemble: create object files from assembler source files. +%.o : %.S + @echo + @echo $(MSG_ASSEMBLING) $< + $(CC) -c $(ALL_ASFLAGS) $< -o $@ + +# Create preprocessed source for use in sending a bug report. +%.i : %.c + $(CC) -E -mmcu=$(MCU) -I. $(CFLAGS) $< -o $@ + + +# Target: clean project. +clean: begin clean_list end + +clean_list : + @echo + @echo $(MSG_CLEANING) + $(REMOVE) $(TARGET).hex + $(REMOVE) $(TARGET).eep + $(REMOVE) $(TARGET).cof + $(REMOVE) $(TARGET).elf + $(REMOVE) $(TARGET).map + $(REMOVE) $(TARGET).sym + $(REMOVE) $(TARGET).lss + $(REMOVE) $(OBJ) + $(REMOVE) $(LST) + $(REMOVE) $(SRC:.c=.s) + $(REMOVE) $(SRC:.c=.d) + $(REMOVE) .dep/* + + + +# Include the dependency files. +-include $(shell mkdir .dep 2>/dev/null) $(wildcard .dep/*) + + +# Listing of phony targets. +.PHONY : all begin finish end sizebefore sizeafter gccversion \ +build elf hex eep lss sym coff extcoff \ +clean clean_list program debug gdb-config + diff --git a/74hc165_piso/main.c b/74hc165_piso/main.c new file mode 100644 index 0000000..80bc177 --- /dev/null +++ b/74hc165_piso/main.c @@ -0,0 +1,141 @@ +/* + * Code to read in 8-bit data from 74HC165 PISO shift register. + * + * The SN74HC165 is an 8-bit parallel-load shift register that, when clocked, + * shift the data toward a serial (QH) output. Parallel-in access to each + * stage is provided by eight individual direct data (A−H) inputs that are + * enabled by a low level at the shift/load (SH/LD) input. The SN74HC165 also + * features a clock-inhibit (CLK INH) function and a complementary serial (QH) + * output. + * + * Clocking is accomplished by a low-to-high transition of the clock (CLK) + * input while SH/LD is held high and CLK INH is held low. The functions of + * CLK and CLK INH are interchangeable. Since a low CLK and a low-to-high + * transition of CLK INH also accomplish clocking, CLK INH should be changed + * to the high level only while CLK is high. Parallel loading is inhibited + * when SH/LD is held high. While SH/LD is low, the parallel inputs to the + * register are enabled independently of the levels of the CLK, CLK INH, or + * serial (SER) input + * + * http://www.datasheetcatalog.org/datasheet2/8/0ue9fx650zw5716zs9zch6ks5uwy.pdf + * + * To compile and upload run: make clean; make; make program; + * + * Copyright 2011 Mika Tuupola + * + * Licensed under the MIT license: + * http://www.opensource.org/licenses/mit-license.php + * + */ + + +#ifndef F_CPU +#define F_CPU 16000000UL +#endif + +#include +#include +#include +#include +#include +#include + +#include "main.h" +#include "uart.h" + +#define SHLD PORTB0 +#define CLK PORTB4 +#define QH PORTB5 + +#define PIN_QH PINB /* This is the only input. */ + +#define DDR_SHLD DDRB +#define DDR_CLK DDRB +#define DDR_QH DDRB + +#define PORT_SHLD PORTB +#define PORT_CLK PORTB +#define PORT_QH PORTB + +void init(void) { + + /* Make PORTD2 (Arduino digital 2) input by clearing bit in DDR */ + //DDRD &= ~(_BV(PORTD2)); + + /* In input mode, when pull-up is enabled, default state of pin becomes ’1′. So even if */ + /* you don’t connect anything to pin and if you try to read it, it will read as 1. Now, */ + /* when you externally drive that pin to zero(i.e. connect to ground / or pull-down), */ + /* only then it will be read as 0. */ + + /* Enable pullups by setting bits in PORT. Default state is now high. */ + //PORTD |= (_BV(PORTD2)); + //PORT_SHLD |= (_BV(SHLD)); + //PORT_CLK |= (_BV(CLK)); + //PORT_QH |= (_BV(QH)); + + /* Make PORTB5 (Arduino digital 13) an output by setting bit in DDR. */ + //DDRB |= _BV(PORTB5); + + DDR_SHLD |= (_BV(SHLD)); /* Output */ + DDR_CLK |= (_BV(CLK)); /* Output */ + DDR_QH &= ~(_BV(QH)); /* Input */ + +} + +uint8_t digital_read(int input_register, int pin) { + return bit_is_set(input_register, pin) != 0 ? 1 : 0; +} + +/* You could use cbi ie &= ~ or sbi ie |= but this makes code more readable. */ +void digital_write(volatile uint8_t *data_port, uint8_t pin, uint8_t value) { + if (0 == value) { + *data_port &= ~(_BV(pin)); + } else { + *data_port |= _BV(pin); + } +} + + +int main(void) { + + init(); + uart_init(); + stdout = &uart_output; + stdin = &uart_input; + + uint8_t i; + uint8_t register_value; + uint8_t pin_value; + + while (1) { + + /* Read in parallel input by setting SH/LD low. */ + digital_write(&PORT_SHLD, SHLD, 0); + //_delay_ms(5); + + /* Freeze data by setting SH/LD high. When SH/LD is high data enters */ + /* to reqisters from SER input and shifts one place to the right */ + /* (Q0 -> Q1 -> Q2, etc.) with each positive-going clock transition. */ + digital_write(&PORT_SHLD, SHLD, 1); + + register_value = 0; + + for(i=0; i<8; i++) { + pin_value = digital_read(PIN_QH, QH); + register_value |= (pin_value << ((8 - 1) - i)); + + printf("%d = %d \n", ((8 - 1) - i), pin_value); + + /* Pulse clock input (CP) LOW-HIGH to read next bit. */ + digital_write(&PORT_CLK, CLK, 0); + //_delay_ms(5); + digital_write(&PORT_CLK, CLK, 1); + } + printf("%d \n", register_value); + + _delay_ms(2000); + + } + return 0; + +} diff --git a/74hc165_piso/main.h b/74hc165_piso/main.h new file mode 100644 index 0000000..26d0812 --- /dev/null +++ b/74hc165_piso/main.h @@ -0,0 +1,2 @@ +static void uart_init(void); +static void init(void); diff --git a/74hc165_piso/timer.c b/74hc165_piso/timer.c new file mode 100644 index 0000000..17db4d0 --- /dev/null +++ b/74hc165_piso/timer.c @@ -0,0 +1,63 @@ +/* + * Low resolution implementation of timer using a 8 bit clock with prescaler, + * etc. Clicks approximately every millisecond. Microseconds are not available, + * and any queries to the function will just return milliseconds * 1000. + * You can use this file when you don't need high resolution timing, and don't care + * about slight clock drift, inaccuracy, etc. For timing most human-related activities, + * though, it should be more than sufficient. + */ +#include "timer.h" + +static volatile uint64_t _timer_millis; + +/* + * Initializes the timer, and resets the timer count to 0. Sets up the ISRs + * linked with timer0. + */ +void timer_init(){ + //Set up the timer to run at F_CPU / 256, in normal mode (we reset TCNT0 in the ISR) + TCCR0A = 0x0; + TCCR0B |= _BV(CS02); + + //Set compare value to be F_CPU / 1000 -- fire interrupt every millisecond + OCR0A = F_CPU / 256 / 1000; + + //Enable compare interrupt + TIMSK0 = _BV(OCIE0A); + + //Reset count variables + _timer_millis = 0; + + //Enable interrupts if the NO_INTERRUPT_ENABLE define is not set. If it is, you need to call sei() elsewhere. +#ifndef NO_INTERRUPT_ENABLE + sei(); +#endif + + DDRB = 0xFF; +} + +/* + * Returns the number of milliseconds which have elapsed since the + * last time timer_init() was called. Overflows after about 49 days. + */ +uint64_t timer_millis(){ + return _timer_millis; +} + +/* + * Returns the number of microseconds which have elapsed since the + * last time timer_init() was called. Overflows after about 71 minutes. + */ +uint64_t timer_micros(){ + return (_timer_millis * 1000); +} + + +/* + * The ISR for timer0 overflow. Increment the _timer_count here, and do the calculcations + * to increment _timer_millis as needed. + */ +ISR(TIMER0_COMPA_vect){ + TCNT0 = 0; + _timer_millis++; +} diff --git a/74hc165_piso/timer.h b/74hc165_piso/timer.h new file mode 100644 index 0000000..448c03d --- /dev/null +++ b/74hc165_piso/timer.h @@ -0,0 +1,25 @@ +#ifndef TIMER_H +#define TIMER_H + +#include +#include + +/* + * Initializes the timer, and resets the timer count to 0. Sets up the ISRs + * linked with timer1. + */ +void timer_init(); + +/* + * Returns the number of milliseconds which have elapsed since the + * last time timer_init() was called. Overflows after about 49 days. + */ +uint64_t timer_millis(); + +/* + * Returns the number of microseconds which have elapsed since the + * last time timer_init() was called. Overflows after about 71 minutes. + */ +uint64_t timer_micros(); + +#endif diff --git a/74hc165_piso/uart.h b/74hc165_piso/uart.h new file mode 100644 index 0000000..20ed356 --- /dev/null +++ b/74hc165_piso/uart.h @@ -0,0 +1,12 @@ +int uart_putchar(char c, FILE *stream); +int uart_getchar(FILE *stream); + +void uart_init(void); + +struct rx_ring; +struct tx_ring; + +/* http://www.ermicro.com/blog/?p=325 */ + +FILE uart_output = FDEV_SETUP_STREAM(uart_putchar, NULL, _FDEV_SETUP_WRITE); +FILE uart_input = FDEV_SETUP_STREAM(NULL, uart_getchar, _FDEV_SETUP_READ); diff --git a/74hc165_piso/uart_async.c b/74hc165_piso/uart_async.c new file mode 100644 index 0000000..e56fa46 --- /dev/null +++ b/74hc165_piso/uart_async.c @@ -0,0 +1,102 @@ +/* Based on Atmel Application Note AVR 306 */ + +#include +#include +#include + +#ifndef BAUD +#define BAUD 9600 +#endif +#include + +#ifndef UART_RX_BUFFER_SIZE +#define UART_RX_BUFFER_SIZE 32 +#endif + +#ifndef UART_TX_BUFFER_SIZE +#define UART_TX_BUFFER_SIZE 256 +#endif + +struct tx_ring { + int buffer[UART_TX_BUFFER_SIZE]; + int start; + int end; +}; + +struct rx_ring { + int buffer[UART_RX_BUFFER_SIZE]; + int start; + int end; +}; + +static struct tx_ring tx_buffer; +static struct rx_ring rx_buffer; + +/* http://www.cs.mun.ca/~rod/Winter2007/4723/notes/serial/serial.html */ + +void uart_init(void) { + + tx_buffer.start = 0; + tx_buffer.end = 0; + + rx_buffer.start = 0; + rx_buffer.end = 0; + + UBRR0H = UBRRH_VALUE; + UBRR0L = UBRRL_VALUE; + + UCSR0C = _BV(UCSZ01) | _BV(UCSZ00); /* 8-bit data */ + UCSR0B = _BV(RXEN0) | _BV(TXEN0); /* Enable RX and TX */ + + sei(); +} + +int uart_putchar(char c, FILE *stream) { + if (c == '\n') { + uart_putchar('\r', stream); + } + + int write_pointer = (tx_buffer.end + 1) % UART_TX_BUFFER_SIZE; + + if (write_pointer != tx_buffer.start){ + tx_buffer.buffer[tx_buffer.end] = c; + tx_buffer.end = write_pointer; + + /* Data available. Enable the transmit interrupt for serial port 0. */ + UCSR0B |= _BV(UDRIE0); + } + + return 0; +} + +int uart_getchar(FILE *stream) { + int read_pointer = (rx_buffer.start + 1) % UART_RX_BUFFER_SIZE; + + rx_buffer.start = read_pointer; + return rx_buffer.buffer[read_pointer]; +} + +ISR(USART_RX_vect) { + int write_pointer = (rx_buffer.end + 1) % UART_RX_BUFFER_SIZE; + + /* Add next byte to ringbuffer if it has space available. */ + if (write_pointer != rx_buffer.start){ + rx_buffer.buffer[rx_buffer.end] = UDR0; + rx_buffer.end = write_pointer; + } +} + +ISR(USART_UDRE_vect){ + int read_pointer = (tx_buffer.start + 1) % UART_TX_BUFFER_SIZE; + + /* Transmit next byte if data available in ringbuffer. */ + if (read_pointer != tx_buffer.end) { + UDR0 = tx_buffer.buffer[read_pointer]; + tx_buffer.start = read_pointer; + } else { + /* Nothing to send. Disable the transmit interrupt for serial port 0. */ + UCSR0B &= ~_BV(UDRIE0); + } +} + +