src/bsv/actual_pinmux.py

   1 import math
   2 from string import digits
   3 try:
   4     from string import maketrans
   5 except ImportError:
   6     maketrans = str.maketrans
   7
   8
   9 # ============== common bsv templates ============ #
  10 # first argument is the io-cell number being assigned.
  11 # second argument is the mux value.
  12 # Third argument is the signal from the pinmap file
  13 mux_wire = '''
  14       rule assign_{2}_on_cell{0}(wrcell{0}_mux=={1});
  15         {2}<=cell{0}_mux_in;
  16       endrule
  17 '''
  18 dedicated_wire = '''
  19       rule assign_{1}_on_cell{0};
  20         {1}<=cell{0}_mux_in;
  21       endrule
  22 '''
  23 # ============================================================
  24 digits = maketrans('0123456789', ' ' * 10)  # delete space later
  25
  26
  27 def get_cell_bit_width(p):
  28     max_num_cells = 0
  29     for cell in p.muxed_cells:
  30         max_num_cells = max(len(cell) - 1, max_num_cells)
  31     return int(math.log(max_num_cells + 1, 2))
  32
  33
  34 def cn(idx):  # idx is an integer
  35     return "cell%s_mux" % str(idx)
  36
  37
  38 def transfn(temp):
  39     """ removes the number from the string of signal name.
  40     """
  41     temp = temp.split('_')
  42     if len(temp) == 2:
  43         temp[0] = temp[0].translate(digits)
  44         temp[0] = temp[0] .replace(' ', '')
  45     return '_'.join(temp)
  46
  47
  48 def fmt(cell, idx):
  49     """ blank entries need to output a 0 to the pin (it could just as
  50         well be a 1 but we choose 0).  reason: blank entries in
  51         the pinmap.txt file indicate that there's nothing to choose
  52         from.  however the user may still set the muxer to that value,
  53         and rather than throw an exception we choose to output... zero.
  54     """
  55     idx += 1
  56     if idx < len(cell):
  57         cell = cell[idx]
  58     else:
  59         cell = ''
  60     return "%s_io" % cell if cell else '0'
  61
  62
  63 def mkcomment(p, cell, idx):
  64     """ returns a comment string for the cell when muxed
  65     """
  66     return ""
  67
  68
  69 def init(p, ifaces):
  70     """ generates the actual output pinmux for each io-cell.  blank lines
  71         need to output "0" to the iopad, if there is no entry in
  72         that column.
  73
  74         text is outputted in the format:
  75             x_out =
  76                 muxer_sel==0 ? a :
  77                 muxer_sel==1 ? b :
  78                 muxer_sel==2 ? 0 :
  79                 d
  80
  81         last line doesn't need selector-logic, obviously.
  82
  83         note that it's *important* that all muxer options be covered
  84         (hence going up to 1<<cell_bitwidth) even if the muxer cells
  85         are blank (no entries), because muxer selection could be to
  86         the last one, and we do not want the "default" (last line)
  87         to be the output.
  88     """
  89     p.cell_bitwidth = get_cell_bit_width(p)
  90     p.pinmux = ' '
  91     global dedicated_wire
  92     fmtstr = "\t\t\twr%s == %d ? %s :%s\n"  # mux-selector format
  93     for cell in p.muxed_cells:
  94         p.pinmux += "      // output muxer for cell idx %s\n" % cell[0]
  95         p.pinmux += "      %s_out=\n" % cn(cell[0])
  96         for i in range(
  97                 0, (1 << p.cell_bitwidth) - 1):  # full mux range (minus 1)
  98             comment = mkcomment(p, cell, i)
  99             p.pinmux += fmtstr % (cn(cell[0]), i, fmt(cell, i), comment)
 100         comment = mkcomment(p, cell, i + 1)
 101         p.pinmux += "\t\t\t" + fmt(cell, i + 1) + comment  # last line
 102         p.pinmux += ";\n"
 103         # ======================================================== #
 104
 105         # check each cell if "peripheral input/inout" then assign its wire
 106         # Here we check the direction of each signal in the dictionary.
 107         # We choose to keep the dictionary within the code and not user-input
 108         # since the interfaces are always standard and cannot change from
 109         # user-to-user. Plus this also reduces human-error as well :)
 110         for i in range(0, len(cell) - 1):
 111             cname = cell[i + 1]
 112             if not cname:  # skip blank entries, no need to test
 113                 continue
 114             temp = transfn(cname)
 115             x = ifaces.getifacetype(temp)
 116             #print (cname, temp, x)
 117             assert x is not None, "ERROR: The signal : " + \
 118                 str(cname) + \
 119                 " of pinmap.txt isn't present \nin the current" + \
 120                 " dictionary. Update dictionary or fix-typo."
 121             if x == "input":
 122                 p.pinmux += \
 123                     mux_wire.format(cell[0], i, "wr" + cname) + "\n"
 124             elif x == "inout":
 125                 p.pinmux += \
 126                     mux_wire.format(cell[0], i, "wr" + cname +
 127                                                 "_in") + "\n"
 128     # ============================================================ #
 129
 130     # ==================  Logic for dedicated pins ========= #
 131     for cell in p.dedicated_cells:
 132         p.pinmux += "      %s_out=%s_io;\n" % (cn(cell[0]), cell[1])
 133         temp = cell[1].translate(digits)
 134         x = ifaces.getifacetype(temp)
 135         if x == "input":
 136             pinmux = pinmux + \
 137                 dedicated_wire.format(cell[0], "wr" + cell[1]) + "\n"
 138         elif x == "inout":
 139             pinmux = pinmux + \
 140                 dedicated_wire.format(cell[0], "wr" + cell[1] + "_in") + "\n"
 141     # =======================================================#