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archieve: homework7 test1

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御坂スバル
2025-05-24 23:29:42 +08:00
parent 097e654ba5
commit 1b64a5df5b
2 changed files with 31 additions and 8 deletions
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homework7/src/homework7.h
+9 -8
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@@ -31,23 +31,24 @@ sbit DB_7 = P2 ^ 7;
// 2. pin number for 74HC138's address pins & enable pin
// 2.1. sbit ADDR0 ~ sbit ADDR2: pin number for 74HC138's address pins
sbit ADDR0 = P1 ^ 0; // @var ADDR0: to A(A0)
sbit ADDR1 = P2 ^ 1; // @var ADDR1: to B(A1)
sbit ADDR2 = P2 ^ 2; // @var ADDR2: to C(A2)
sbit ADDR1 = P1 ^ 1; // @var ADDR1: to B(A1)
sbit ADDR2 = P1 ^ 2; // @var ADDR2: to C(A2)
// 2.2. sbit ADDR3 & sbit ENLED: pin number for 74HC138's enable pin
sbit ADDR3 = P2 ^ 3; // @var ADDR3: to E1
sbit ENLED = P2 ^ 4; // @var ENLED: to E2 & E3
sbit ADDR3 = P1 ^ 3; // @var ADDR3: to E2
sbit ENLED = P1 ^ 4; // @var ENLED: to E3
// functions:
// 1. void switch_138(unsigned char n): switch the 74HC138's address to n
void switch_138(unsigned char n)
{
bit A0, A1, A2;
// @subsection: enable the 74HC138
ENLED = 0;
ADDR3 = 1;
ADDR3 = 0;
// @subsection: turn n to 3 bit binary number
bit A0 = n & 0x01;
bit A1 = (n >> 1) & 0x01;
bit A2 = (n >> 2) & 0x01;
A0 = n & 0x01;
A1 = (n >> 1) & 0x01;
A2 = (n >> 2) & 0x01;
// @subsection: switch the 74HC138's address to n
ADDR0 = A0;
ADDR1 = A1;