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# -*- coding: utf-8 -*-
# Copyright (c) 2007 Johannes Hölzl <johannes.hoelzl@gmx.de>
#
# This library is covered by the GNU LGPL, read LICENSE for details.
# For documentation of the baudrate table see:
#
# [AN205] Silicon Labs Application Note 205 Rev. 0.3
# http://www.silabs.com/public/documents/tpub_doc/anote/Microcontrollers/Interface/en/an205.pdf
import re
from ConfigParser import ConfigParser
import cp210x
from cp210x import VALUES, SIZE_BAUDRATES
__all__ = ['read_file', 'write_file', 'update_values', 'PrescalerIsZero',
'ValuesFileError']
class ValuesError(StandardError):
pass
class PrescalerIsZero(ValuesError):
pass
class ValuesFileError(ValuesError):
pass
version_pattern = re.compile(r'^\s*(\d\d?)\.(\d\d?)\s*$')
def read_version(s):
match = version_pattern.match(s)
if match is None:
raise ValueError("Version does not match 'xx.yy'")
return (int(match.group(1)), int(match.group(2)))
def write_version(v):
return "%d.%02d" % v
def read_hex(s):
return int(s.strip(), 16)
def write_hex(num):
return "%04X" % num
def write_bool(b):
if b:
return 'yes'
else:
return 'no'
def read_bool(s):
s = s.strip().lower()
if s not in ['true', 'yes', 'false', 'no']:
raise ValueError("Boolean must be either 'true', 'yes', 'false' or 'no'.")
return s in ['true', 'yes']
def read_baudrate_info(s):
values = s.split(',')
if len(values) != 3:
raise ValueError("Baudrate info must be three comma-separated items")
try:
baudgen = read_hex(values[0])
except ValueError:
raise ValueError("The first baudrate info must be a hex-value")
try:
timer0 = read_hex(values[1])
except ValueError:
raise ValueError("The second baudrate info must be a hex-value")
try:
prescale = int(values[2])
except ValueError:
raise ValueError("The thirdbaudrate info must be a number")
return (baudgen, timer0, prescale)
TYPES = {
'boolean': (read_bool, write_bool),
'int': (int, str),
'id': (read_hex, write_hex),
'string': (str, str),
'version': (read_version, write_version),
}
def read_file(fp):
cp = ConfigParser()
if isinstance(fp, str):
cp.read([fp])
else:
cp.readfp(fp)
values = {}
for name, type in VALUES:
if name is 'baudrate_table':
continue
reader, _ = TYPES[type]
if cp.has_option('usb device', name):
try:
values[name] = reader(cp.get('usb device', name))
except ValueError, err:
raise ValuesFileError("Key '%s': %s" % (name, str(err)))
if cp.has_section('baudrate table'):
baudrate_table = []
for name, value in cp.items('baudrate table'):
try:
baudrate = int(name)
except ValueError:
raise ValuesFileError("Key names in 'baudrate table' must be"
" baudrate numbers.")
try:
baudrate_table.append(read_baudrate_info(value) + (baudrate, ))
except ValueError, err:
raise ValuesFileError("Wrong baudrate info %i: %s"
% (baudrate, str(err)))
baudrate_table.sort(key=(lambda i: i[3]), reverse=True)
values['baudrate_table'] = baudrate_table
return values
def write_file(fp, values):
fp.write("[usb device]\n")
for name, type in VALUES:
if name == 'baudrate_table':
continue
_, writer = TYPES[type]
if name in values:
fp.write("%s = %s\n" % (name, writer(values[name])))
if 'baudrate_table' in values:
fp.write("\n")
fp.write("[baudrate table]\n")
for (baudgen, timegen, prescaler,
baudrate) in sorted(values['baudrate_table'], key=(lambda i: i[3]),
reverse=True):
fp.write("%7d = %04X, %04X, %d # %s\n"
% (baudrate, baudgen, timegen, prescaler,
show_baudrate(baudgen, timegen, prescaler)))
def calc_baudrate(baudgen, timegen, prescaler):
# This formulas are from AN205 page 5.
if prescaler == 0:
raise PrescalerIsZero("Prescaler is 0")
baudrate = (24000000. / prescaler) / (0x10000 - baudgen)
return (baudrate, (0x10000 - timegen) * 2)
def show_baudrate(baudgen, timegen, prescaler):
try:
baudrate, timeout = calc_baudrate(baudgen, timegen, prescaler)
except PrescalerIsZero:
return "Wrong data, Prescaler is 0."
if timeout >= 1000:
timeout = "%1.3f ms" % (float(timeout) / 1000)
else:
timeout = "%d us" % timeout
if baudrate is None:
return ", %s" % (baudrate, timeout)
else:
return "%7.0f Baud, %s" % (baudrate, timeout)
def update_values(v, new, dev):
old_baudrate_table = v.get('baudrate_table')
new_baudrate_table = new.get('baudrate_table')
v.update(new)
# update baudrate table
# it is needed, that the baudrate table has 32 entries when it is written
# to the eeprom or device.
if ((old_baudrate_table is not None or new_baudrate_table is not None) and
(new_baudrate_table is None or
len(new_baudrate_table) < SIZE_BAUDRATES)):
if old_baudrate_table is not None:
if len(old_baudrate_table) < SIZE_BAUDRATES:
baudrate_table = old_baudrate_table
else:
baudrate_table = list(merge_baudrate_table(dev.baudrate_table,
old_baudrate_table))
else:
baudrate_table = dev.baudrate_table
if new_baudrate_table:
baudrate_table = list(merge_baudrate_table(baudrate_table,
new_baudrate_table))
v['baudrate_table'] = baudrate_table
def merge_baudrate_table(old, new):
for (old_info, (start, stop)) in zip(old, REQUEST_BAUDRATE_RANGES):
for baudgen, timer, prescaler, baudrate in new:
if ((start is None or baudrate <= start) and
baudrate >= stop):
yield (baudgen, timer, prescaler, baudrate)
break
else:
yield old_info
REQUEST_BAUDRATE_RANGES = [
# The table data is from AN205 Table 1 on page 1.
# Start End Default Baudrate
(None, 2457601), # Undefined
(2457600, 1474561), # Undefined
(1474560, 1053258), # Undefined
(1053257, 670255), # 921600
( 670254, 567139), # 576000
( 567138, 491521), # 500000
( 491520, 273067), # 460800
( 273066, 254235), # 256000
( 254234, 237833), # 250000
( 237832, 156869), # 230400
( 156868, 129348), # 153600
( 129347, 117029), # 128000
( 117028, 77609), # 115200
( 77608, 64112), # 76800
( 64111, 58054), # 64000
( 58053, 56281), # 57600
( 56280, 51559), # 56000
( 51558, 38602), # 51200
( 38601, 28913), # 38400
( 28912, 19251), # 28800
( 19250, 16063), # 19200
( 16062, 14429), # 16000
( 14428, 9613), # 14400
( 9612, 7208), # 9600
( 7207, 4804), # 7200
( 4803, 4001), # 4800
( 4000, 2401), # 4000
( 2400, 1801), # 2400
( 1800, 1201), # 1800
( 1200, 601), # 1200
( 600, 301), # 600
( 300, 57), # 300
]
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