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ecp5: Allow setting drive strength for LVCMOS33D IOs

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This commit is contained in:
Mike Walters 2020-05-11 20:19:15 +01:00
parent 0faf07aac8
commit 5b660e3432
1 changed files with 19 additions and 0 deletions
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19
ecp5/bitstream.cc
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@ -915,6 +915,25 @@ void write_bitstream(Context *ctx, std::string base_config_file, std::string tex
static bool drive_3v3_warning_done = false;
if (iotype == "LVCMOS33") {
cc.tiles[pio_tile].add_enum(pio + ".DRIVE", str_or_default(ci->attrs, ctx->id("DRIVE"), "8"));
} else if (iotype == "LVCMOS33D") {
if (bel.location.y == 0) {
// Pseudo differential top IO
NPNR_ASSERT(dir == "OUTPUT");
NPNR_ASSERT(pio == "PIOA");
std::string cpio_tile = get_comp_pio_tile(ctx, bel);
cc.tiles[pio_tile].add_enum("PIOA.DRIVE", str_or_default(ci->attrs, ctx->id("DRIVE"), "12"));
cc.tiles[cpio_tile].add_enum("PIOB.DRIVE", str_or_default(ci->attrs, ctx->id("DRIVE"), "12"));
} else {
std::string other;
if (pio == "PIOA")
other = "PIOB";
else if (pio == "PIOC")
other = "PIOD";
else
log_error("cannot set DRIVE on differential IO at location %s\n", pio.c_str());
cc.tiles[pio_tile].add_enum(pio + ".DRIVE", str_or_default(ci->attrs, ctx->id("DRIVE"), "12"));
cc.tiles[pio_tile].add_enum(other + ".DRIVE", str_or_default(ci->attrs, ctx->id("DRIVE"), "12"));
}
} else {
if (!drive_3v3_warning_done)
log_warning("Trellis limitation: DRIVE can only be set on 3V3 IO pins.\n");