uzix/zx-sizif-xxs
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improve compatibility with slower sram chips

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This commit is contained in:
Eugene Lozovoy
2022-10-31 21:49:02 +03:00
parent 1189d41266
commit 993c336507
9 changed files with 118 additions and 84 deletions
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36
fpga/rtl/top.sv
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@ -60,7 +60,6 @@ wire magic_reboot, magic_beeper;
wire up_active;
wire clkwait;
wire [2:0] rampage128;
wire div_wait;
wire init_done;
wire screen_fetch, screen_fetch_next;
@ -74,8 +73,8 @@ always @(posedge clk28 or negedge rst_n) begin
bus_memreq <= 0;
end
else if (!screen_fetch && !screen_fetch_next) begin
bus.a_reg <= bus.a;
bus.d_reg <= bus.d;
bus.a_reg <= {a[15:13], va[12:0]};
bus.d_reg <= vd;
bus_ioreq <= n_iorq == 1'b0 && n_m1 == 1'b1;
bus_memreq <= n_mreq == 1'b0 && n_rfsh == 1'b1;
end
@ -86,16 +85,18 @@ always @(posedge clk28 or negedge rst_n) begin
bus_memreq <= 0;
end
end
assign bus.a = {a[15:13], va[12:0]};
assign bus.d = vd;
assign bus.iorq = ~n_iorq;
assign bus.mreq = ~n_mreq;
assign bus.m1 = ~n_m1;
assign bus.rfsh = ~n_rfsh;
assign bus.rd = ~n_rd;
assign bus.wr = ~n_wr;
assign bus.ioreq = bus_ioreq & ~n_iorq;
assign bus.memreq = bus_memreq & ~n_mreq;
always @(posedge clk168) begin
bus.a <= {a[15:13], va[12:0]};
bus.d <= vd;
bus.iorq <= ~n_iorq;
bus.mreq <= ~n_mreq;
bus.m1 <= ~n_m1;
bus.rfsh <= ~n_rfsh;
bus.rd <= ~n_rd;
bus.wr <= ~n_wr;
end
assign bus.ioreq = bus_ioreq & bus.iorq;
assign bus.memreq = bus_memreq & bus.mreq;
/* RESET */
@ -122,6 +123,7 @@ screen screen0(
.clk28(clk28),
.machine(machine),
.turbo(turbo),
.border(screen_border),
.r(r),
@ -131,7 +133,7 @@ screen screen0(
.vsync(vsync),
.hsync(hsync),
.fetch_allow((!bus.iorq && !bus.mreq) || bus.rfsh || clkwait),
.fetch_allow((!bus.iorq && !bus.mreq) || bus.rfsh || (clkwait && turbo == TURBO_NONE)),
.fetch(screen_fetch),
.addr(screen_addr),
.fetch_next(screen_fetch_next),
@ -212,9 +214,8 @@ cpucontrol cpucontrol0(
.hc(hc),
.rampage128(rampage128),
.machine(machine),
.screen_contention(screen_contention),
.turbo(turbo),
.ext_wait_cycle(div_wait),
.screen_contention(screen_contention),
.init_done_in(init_done),
.n_rstcpu(n_rstcpu),
@ -411,8 +412,7 @@ divmmc divmmc0(
.map(div_map),
.automap(div_automap),
.ram(div_ram),
.ramwr_mask(div_ramwr_mask),
.cpuwait(div_wait)
.ramwr_mask(div_ramwr_mask)
);
assign sd_mosi_tape_out = (!divmmc_en && !zc_en)? tape_out : sd_mosi0;