small_jtag_test/add.py

   1 # generate add.il ilang file with: python3 add.py
   2 #
   3
   4 from nmigen import Elaboratable, Signal, Module, Const, DomainRenamer
   5 from nmigen.cli import verilog
   6
   7 # to get c4m-jtag
   8 # clone with $ git clone gitolite3@git.libre-soc.org:c4m-jtag.git
   9 #            $ git clone gitolite3@git.libre-soc.org:nmigen-soc.git
  10 # for each:  $ python3 setup.py develop --user
  11
  12 from c4m.nmigen.jtag.tap import TAP, IOType
  13
  14
  15 class ADD(Elaboratable):
  16     def __init__(self, width):
  17         self.a      = Signal(width)
  18         self.b      = Signal(width)
  19         self.f      = Signal(width)
  20
  21         # set up JTAG
  22         self.jtag = TAP(ir_width=4)
  23         self.jtag.bus.tck.name = 'jtag_tck'
  24         self.jtag.bus.tms.name = 'jtag_tms'
  25         self.jtag.bus.tdo.name = 'jtag_tdo'
  26         self.jtag.bus.tdi.name = 'jtag_tdi'
  27
  28         # have to create at least one shift register
  29         self.sr = self.jtag.add_shiftreg(ircode=4, length=3)
  30
  31         # sigh and one iotype
  32         self.ios = self.jtag.add_io(name="test", iotype=IOType.In)
  33
  34     def elaborate(self, platform):
  35         m = Module()
  36
  37         m.submodules.jtag = jtag = self.jtag
  38         m.d.comb += self.sr.i.eq(self.sr.o) # loopback test
  39
  40         # do a simple "add"
  41         m.d.sync += self.f.eq(self.a + self.b)
  42         m.d.sync += self.f[0].eq(Const(0, 1))
  43
  44         return m
  45
  46
  47 def create_verilog(dut, ports, test_name):
  48     vl = verilog.convert(dut, name=test_name, ports=ports)
  49     with open("%s.v" % test_name, "w") as f:
  50         f.write(vl)
  51
  52 if __name__ == "__main__":
  53     alu = DomainRenamer("sys")(ADD(width=4))
  54     create_verilog(alu, [alu.a, alu.b, alu.f,
  55                        alu.jtag.bus.tck,
  56                         alu.jtag.bus.tms,
  57                         alu.jtag.bus.tdo,
  58                         alu.jtag.bus.tdi], "add")