139 lines
3.8 KiB
Python
139 lines
3.8 KiB
Python
from time import time
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from sys import argv
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from time import sleep
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from RPi.GPIO import IN, OUT
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import RPi.GPIO as GPIO
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from opcodes import opcodes_d
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# EEPROM AT28C256 Pin names and RPi GPIO Pin Numbers
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# b means bar = inverted
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gpio_l = [2, 3, 4, 17, 27, 22, 10, 9, 11, 5, 6, 13, 19, 26]
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gpio_r = [14, 15, 18, 23, 24, 25, 8, 7, 12, 16, 20, 21]
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#
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# Defining which 6502 pin goes to which GPIO pin
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#
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"""
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IO = gpio_r[-8:] # 8 io pins
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IO.reverse()
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A = [13, 6, 5, 11, 9, 10, 22, 27,
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17, 4, 3, 2,
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23, 18, 15]
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# OEb = 26 # Output Enable
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RWb = 19 # Write Enable
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CEb = 14 # Chip Enable is hooked up to A15 on the processor
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PHI2 = 26
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controls = [CEb, RWb, PHI2]
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"""
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A = [
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27, 22, 10, 9, 11, 5, 6, 13, # A0-A7
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4, 2, 18, 3, # A8-A11
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23, 17, 15 # A12-A14
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]
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IO = [ 24, 25, 8, 7, 12, 16, 20, 21 ]
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RWb = 19 # Write Enable
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CEb = 14 # Chip Enable is hooked up to A15 on the processor
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PHI2 = 26
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controls = [CEb, RWb, PHI2]
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# Address setup time
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t_AS = 300e-9
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# setup the pins
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GPIO.setmode(GPIO.BCM)
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for pin in controls:
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GPIO.setup(pin, IN)
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for pin in A:
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GPIO.setup(pin, IN)
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def setup_pins(IOdirection=OUT):
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# OUT when writing and IN when reading
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for pin in IO:
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if IOdirection == OUT:
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GPIO.setup(pin, IOdirection, initial=0)
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elif IOdirection == IN:
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GPIO.setup(pin, IOdirection)
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# print("setup pins", IOdirection)
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def print_pins():
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for i in range(len(A)):
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print(f"A{i} - {A[i]}")
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for i in range(len(IO)):
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print(f"IO{i} - {IO[i]}")
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print(f"CEb - {CEb}")
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print(f"RWb - {RWb}")
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print(f"PHI2 - {PHI2}")
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def get_8_bit(l: list):
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for i in range(len(l)):
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l[i] = format(l[i], f"08b") # get the 8-bit bin value
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return l
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def check_enable():
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# assumes the EEPROM is only hooked up via CE. If CE is low, it will ouput data
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if GPIO.input(CEb) == 0 and GPIO.input(RWb) == 1:
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return True
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return False
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def decode_address():
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ad_s = ""
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for i in range(len(A)):
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ad_s += str(GPIO.input(A[len(A)-1-i]))
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return int(ad_s, 2)
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def simulate(path, verbose=True):
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with open(path, "rb") as file:
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bindata = file.read()
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data = []
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for i in range(len(bindata)):
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data.append(format(bindata[i], "08b"))
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while True:
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GPIO.cleanup(IO)
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setup_pins(IN)
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# address is set on falling edge
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channel = GPIO.wait_for_edge(PHI2, GPIO.FALLING, timeout=1000) # allow for KeyboardInterrupts
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if channel is None:
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continue
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# wait an address setup time, dependant on clock speed!
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sleep(t_AS)
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enable = check_enable()
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address = decode_address()
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# put the data on the bus
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if enable:
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setup_pins(OUT)
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for i in range(8):
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if data[address][i] == "0":
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GPIO.output(IO[7-i], 0)
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else:
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GPIO.output(IO[7-i], 1)
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# wait the output hold time
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if verbose:
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print(f"OUT|||{format(address + 0x8000, '015b')} - {data[address]}|||{format(address + 0x8000, '04x')} - {format(int(data[address], 2), '02x')}", end="")
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if int(data[address], 2) in opcodes_d:
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print(f" ||| {opcodes_d[int(data[address], 2)]}")
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else:
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print("")
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elif verbose:
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data_in = ""
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for i in range(8):
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data_in += str(GPIO.input(IO[7-i]))
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print(f"IN |||{format(address, '016b')} - {data_in}|||{format(address, '04x')} - {format(int(data_in, 2), '02x')}")
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if len(argv) > 1:
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try:
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simulate(argv[1])
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except KeyboardInterrupt:
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GPIO.cleanup()
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else:
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print("No filepath given. Printing Pin-Settings")
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print_pins()
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# if performing action from this script, put the code HERE:
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GPIO.cleanup()
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