uzix/zx-sizif-128
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cpld: do not stop screen render on reset

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UzixLS
2020-10-26 21:56:58 +03:00
parent e2ef8d7c22
commit 96fd68f076
3 changed files with 17 additions and 30 deletions
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45
cpld/top.v
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@ -80,11 +80,8 @@ end
reg [4:0] blink_cnt;
wire blink = blink_cnt[$bits(blink_cnt)-1];
always @(posedge n_int or negedge rst_n) begin
if (!rst_n)
blink_cnt <= 0;
else
blink_cnt <= blink_cnt + 1'b1;
always @(posedge n_int) begin
blink_cnt <= blink_cnt + 1'b1;
end
reg [2:0] border;
@ -99,32 +96,23 @@ wire screen_show = (vc < V_AREA) && (hc >= SCREEN_DELAY) && (hc < H_AREA + SCREE
wire screen_update = (vc < V_AREA) && (hc < H_AREA) && hc0[3:0] == 4'b1111;
wire border_update = (hc0[3:0] == 4'b1111) || (screen_show == 0);
always @(posedge clk14 or negedge rst_n) begin
if (!rst_n) begin
screen_read <= 0;
attr <= 0;
bitmap <= 0;
attr_next <= 0;
bitmap_next <= 0;
end
else begin
screen_read <= n_mreq == 1'b1 && n_iorq == 1'b1;
always @(posedge clk14) begin
screen_read <= n_mreq == 1'b1 && n_iorq == 1'b1;
if (attr_read)
attr_next <= vd;
if (bitmap_read)
bitmap_next <= vd;
if (attr_read)
attr_next <= vd;
if (bitmap_read)
bitmap_next <= vd;
if (screen_update)
attr <= attr_next;
else if (border_update)
attr[7:3] <= {2'b00, border};
if (screen_update)
attr <= attr_next;
else if (border_update)
attr[7:3] <= {2'b00, border};
if (screen_update)
bitmap <= {bitmap_next[7] ^ (attr_next[7] & blink), bitmap_next[6:0]};
else if (hc0[0])
bitmap <= {bitmap[6] ^ (attr[7] & blink), bitmap[5:0], 1'b0};
end
if (screen_update)
bitmap <= {bitmap_next[7] ^ (attr_next[7] & blink), bitmap_next[6:0]};
else if (hc0[0])
bitmap <= {bitmap[6] ^ (attr[7] & blink), bitmap[5:0], 1'b0};
end
@ -155,7 +143,6 @@ always @(posedge clk14)
n_int <= ~(vc == 239 && hc[8:6] == 3'b101);
/* CLOCK */
assign clkcpu = hc[0];