summaryrefslogtreecommitdiffstats
path: root/serial.v
diff options
context:
space:
mode:
authorH. Peter Anvin <hpa@zytor.com>2010-10-24 23:17:48 -0700
committerH. Peter Anvin <hpa@zytor.com>2014-02-10 18:07:48 -0800
commit4a79845d59a687a807cf2138a984b0ba047b6375 (patch)
treeeddbfd4272daca0942444f3ee974215f8d43e93c /serial.v
parentfe263a38d1c42f6d70d4075da491906345f189ce (diff)
downloadabc8000-4a79845d59a687a807cf2138a984b0ba047b6375.tar.gz
abc8000-4a79845d59a687a807cf2138a984b0ba047b6375.tar.xz
abc8000-4a79845d59a687a807cf2138a984b0ba047b6375.zip
serial: use positive-logic msel instead of negative-logic CS#
For consistency with the other units, use a positive msel signal instead of a negative-logic CS# signal (although period external logic would have used negative signalling for speed reasons due to assymetric drive.)
Diffstat (limited to 'serial.v')
-rw-r--r--serial.v6
1 files changed, 3 insertions, 3 deletions
diff --git a/serial.v b/serial.v
index eaeccf2..76abceb 100644
--- a/serial.v
+++ b/serial.v
@@ -39,7 +39,7 @@ module serial (
output tty_txd, // Serial port data out
input tty_rxd, // Serial port data in
- input cs_n, // Unit (card/chip) select, AS#
+ input msel, // Unit (card/chip) select, AS#
input cpu_a, // Address bit
input [7:0] cpu_do, // CPU data out (cpu->card)
output [7:0] cpu_di, // CPU data in (card->cpu)
@@ -47,8 +47,8 @@ module serial (
);
// CPU strobes
- wire cpu_rd = ~cs_n & cpu_r_wn;
- wire cpu_wr = ~cs_n & ~cpu_r_wn;
+ wire cpu_rd = msel & cpu_r_wn;
+ wire cpu_wr = msel & ~cpu_r_wn;
wire cpu_rdd = cpu_rd & ~cpu_a;
wire cpu_wrd = cpu_wr & ~cpu_a;