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Invalid HFOSC divider value '0b0' on lattice ICE40 #520

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davidlattimore opened this issue Nov 2, 2020 · 1 comment · Fixed by #521
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Invalid HFOSC divider value '0b0' on lattice ICE40 #520

davidlattimore opened this issue Nov 2, 2020 · 1 comment · Fixed by #521
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bug
Milestone
0.3

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@davidlattimore
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If I run the following python script:

from nmigen import *

class TestLEDModule( Elaboratable ):
  def __init__( self ):
    self.count = Signal( 32, reset = 0 )
  def elaborate( self, platform ):
    m = Module()
    m.d.sync += self.count.eq( self.count + 1 )
    return m

from nmigen_boards.upduino_v2 import *
if __name__ == "__main__":
  dut = TestLEDModule()
  UpduinoV2Platform().build( dut )

I get the following error:

ERROR: Invalid HFOSC divider value '0b0' - expecting 0b00, 0b01, 0b10 or 0b11
ERROR: Packing design failed.

Making the following change appears to fix it

diff --git a/nmigen/vendor/lattice_ice40.py b/nmigen/vendor/lattice_ice40.py
index 14026fa..d5e4dd6 100644
--- a/nmigen/vendor/lattice_ice40.py
+++ b/nmigen/vendor/lattice_ice40.py
@@ -379,7 +379,7 @@ class LatticeICE40Platform(TemplatedPlatform):
                 m.submodules += Instance("SB_HFOSC",
                                          i_CLKHFEN=1,
                                          i_CLKHFPU=1,
-                                         p_CLKHF_DIV="0b{0:b}".format(self.hfosc_div),
+                                         p_CLKHF_DIV="0b{0:02b}".format(self.hfosc_div),
                                          o_CLKHF=clk_i)
                 delay = int(100e-6 * self.default_clk_frequency)
             # Internal low-speed clock: 10 KHz.

I've only just started using nmigen today, so it's always possible that I'm doing some thing silly. I'm happy to send a PR if you'd like.
@whitequark whitequark added the bug label Nov 2, 2020
@whitequark
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This is clearly a bug--most likely, the code in question predates improved syntax checking in nextpnr. Please send a PR.

davidlattimore pushed a commit to davidlattimore/nmigen that referenced this issue Nov 2, 2020
Lattice ICE40: Zero-pad CLKHF_DIV
470024f 
Fixes amaranth-lang#520
@davidlattimore davidlattimore mentioned this issue Nov 2, 2020
Merged
@whitequark whitequark added this to the 0.3 milestone Nov 2, 2020
whitequark pushed a commit that referenced this issue Nov 2, 2020
@davidlattimore
vendor.lattice_ice40: zero-pad CLKHF_DIV in SB_HFOSC instance.
781a3aa 
Fixes #520.
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Lattice ICE40: Zero-pad CLKHF_DIV davidlattimore/nmigen
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@whitequark @davidlattimore